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La versión honesta

No soy un purista de la vida fuera de la red — esto es sobre resiliencia

Déjame ser honesto sobre lo que esto es y lo que no es. No vivo un sueño de impacto cero. Tengo excusados de descarga — rompí la regla de “fuera de la red” de usar baño composta — aunque instalé el tanque más chico que encontré y le metí una botella de 600 ml adentro, lo que baja cada descarga a unos 3.1 litros. Uso una bomba con electricidad de la red. Esto no es ideología; es una casa sin conexión de agua, hecha para funcionar con lo que cae en el techo.

Pasé años trabajando en desarrollo internacional en zonas rurales de Guatemala — en un momento como especialista en innovación, donde probé una bolsa de almacenamiento de agua de lluvia de África que se montaba bajo un techo como una pequeña carpa. Abastecer a mi propia familia necesitaba algo mucho más robusto que esa bolsa, y un sistema de agua fuera de la red fue en lo que terminé.

El problema real

El verdadero problema del agua de lluvia no es captarla

Si estás planeando captar agua de lluvia en México, lo primero que hay que aprender es que captar la lluvia es la parte fácil. Antes de construir nada, pensaba que el agua de lluvia era, sobre todo, un tema de captación: apuntas el techo a un tambo y ya. Resultó que el verdadero reto eran otras tres cosas, y solo una de ellas es fácil.

Los tres retos del agua de lluvia

La tercera fila es todo el juego. Mi techo de lámina — el que abastece la casa — mide cerca de 50 m² (5 × 10 m), y en los días más fuertes puedo captar hasta 5,000 litros en un solo día. Pero eso requiere una verdadera tormenta tropical: un milímetro de lluvia en un metro cuadrado es un litro, así que 5,000 litros de 50 m² significan unos 100 mm de lluvia en un día — algo que solo pasa un puñado de veces al año. Después de que terminan las lluvias, hacia mediados de noviembre, vives de lo que guardaste en octubre y noviembre, con apenas algunas lluvias ligeras y poco frecuentes hasta que llega la siguiente temporada de lluvias en mayo o junio. Ese largo tramo seco es justo la razón por la que la primera decisión de verdad es el almacenamiento.

Almacenamiento

Empieza por el almacenamiento — es lo único que no puedes rehacer

Casi todo en un sistema de agua fuera de la red se puede ajustar después. La cisterna no. Es concreto colado bajo tierra, y vives con el tamaño que elegiste.

La mía es una cisterna de concreto de unos 10,000 litros. Funciona — ha sostenido a una familia de cuatro durante las temporadas secas. Pero si la volviera a colar, iría a 12,000–15,000 litros, porque el almacenamiento es lo que cierra la brecha entre los meses que llueve y los que no. Una vez que está hecha, agrandarla significa romper concreto. La construcción en sí — lo que costó, cómo está revestida — está en la guía del sistema de agua, junto con la bomba y el tinaco; aquí el punto es más simple: erra hacia lo grande. El almacenamiento es el seguro más barato contra una temporada seca larga, y lo más difícil de agregar después.

Filtrado

El error es filtrar el agua de lluvia demasiado fino, demasiado pronto

Esta es la parte que no es intuitiva: en el punto de captación filtro menos, no más. Un filtro fino es justo lo peor cuando 5,000 litros quieren pasar en una tarde — se tapa, se atasca, y la lluvia que querías captar se va por la orilla.

Así que mi primer filtro es deliberadamente tosco: un tambo de 50 litros con piedras grandes (10–15 cm) abajo y piedras más chicas (unos 5 cm) arriba. Sin medio fino, nada que ahogue el flujo. Saca las hojas y la arenilla y deja pasar el volumen. La limpieza de verdad pasa más adelante en la cadena, donde no tiene que mantenerle el ritmo a un aguacero:

Capta rápido y sucio. Limpia despacio y seguido.

La calidad me sorprendió. El agua no deja sarro en las regaderas, los lavabos ni los excusados, y para mi gusto sabe más limpia que el agua de la red — prefiero tomarla a depender solo de garrafones rellenados. Pero seré claro: el sabor no es una prueba de seguridad. Yo la tomo — sobre todo como té, así que va hervida — y no he tenido problemas, pero esa es mi experiencia en mi casa, no un consejo. El agua que escurre del techo puede traer bacterias y lo que sea que haya en tu techo. Si vas a tomar agua de lluvia, fíltrala y analízala bien, y trata el permiso de pozo y la calidad del agua como algo que hay que confirmar con alguien calificado para tu propio terreno.

Hacia dónde va el agua

A dónde va el agua de cada techo

No toda el agua de lluvia es igual, y el techo de donde viene decide para qué sirve. El agua de mi techo de lámina es notablemente más limpia que la que escurre del techo de concreto — así que las mando a trabajos distintos en lugar de mezclarlas.

Agua por techo — cada fuente a su trabajo

Esta es una razón más por la que la decisión del techo y la decisión del agua están ligadas — el material que pones arriba cambia el agua que puedes captar abajo. Entro más a fondo en esa disyuntiva en techo de lámina vs techo de concreto en México. También es la razón por la que, si tu terreno no tiene conexión, el techo y la captación deben planearse juntos desde el inicio, no improvisarse después — el mismo punto que hago sobre comprar un terreno en México sin servicios.

Excedente

Planear para cuando sobra agua

El otro lado de captar 5,000 litros en un día es que, en temporada de lluvias, te sobra mucha más agua de la que puedes guardar o usar — y el agua que no diriges a propósito termina donde no la quieres. El techo de lámina llena la cisterna principal; mi techo de concreto y el drenaje francés pueden entregar más o menos lo mismo otra vez, pero los tanques a los que alimentan son chicos — un Rotoplas de 1,000 y uno de 500 litros — así que en un día de tormenta fuerte casi toda esa segunda corriente simplemente se desborda. Un tubo de desvío manda el excedente hacia la calle una vez que los tanques están llenos. Así que parte de tener un sistema fuera de la red es dirigir el excedente a propósito — y aceptar que vas a perder el resto.

Mi solución es sencilla y barata. Uso tubería de PVC con llaves en las uniones para poder cambiar el flujo de varias formas — desviándolo, por ejemplo, hacia un tambo enterrado en el jardín, para guardar agua para las plantas y los animales. En una pendiente, los drenajes franceses hacen el mismo trabajo con el escurrimiento de piso: alimentan el mismo almacenamiento en lugar de dejar que el agua abra canales en tu terreno.

Lo que cambiaría

Qué haría diferente

Colaría una cisterna más grande — de 12,000 a 15,000 litros — porque el almacenamiento es lo que te sostiene durante la temporada seca, y es lo único que no puedes agrandar después. Planearía la captación y el techo juntos, en vez de tratar la recolección como algo que se agrega una vez levantada la casa. Y aceptaría más pronto que la parte que suena fácil (captar la lluvia) es trivial comparada con las partes que nadie se imagina: guardarla, dirigir el excedente, y lidiar con lo que sale de la casa.

Vivir con poca agua

Cómo se siente de verdad vivir con poca agua

La gente se imagina que vivir sin red de agua significa privaciones. Sobre todo significa atención — y no hay un solo número, hay un rango. Dónde caigas dentro de ese rango depende, sobre todo, de dos decisiones: cómo lavas la ropa, y qué tipo de excusado tienes.

Uso de agua por semana — dónde caes en el rango

El gran cambio es la lavandería — lavar ropa de verdad consume mucha agua, y es la mayor parte de la diferencia entre esas dos columnas. Los excusados son la otra palanca: los míos son de descarga normal, ajustados a unos 3.1 litros, pero un baño composta recuperaría suficiente como para bañarte más seguido y aun así quedar cerca del extremo frugal. De cualquier forma, vale la pena saber algo: lavar trastes puede usar tanta agua como una regadera, según tus llaves y cómo lo hagas — así que el ahorro muchas veces se esconde en las tareas cotidianas, no en las obvias.

Lo que ganas a cambio es independencia y, honestamente, mejor agua — suave, sin sarro, y que no llega en pipa. Lo que pierdes es la posibilidad de olvidarte del tema. Vigilas la cisterna durante los meses secos como otros vigilan el medidor de gasolina. Después de unos años, ya es solo un ritmo, no una carga.

La lluvia es la parte fácil. Todo lo que decide si tienes agua en abril pasa antes de que caiga la primera gota.

Preguntas

Preguntas frecuentes

¿De verdad se puede vivir en una casa con agua de lluvia en México?

En mi terreno en Chiapas, sí — sin conexión a la red, el agua de lluvia de los techos es mi fuente principal, almacenada en una cisterna de 10,000 litros y bombeada a un tinaco. Que te funcione a ti depende de tu lluvia, el área de tu techo, el tamaño del almacenamiento y cuánto dura tu temporada seca. El factor limitante casi siempre es el almacenamiento, no cuánta lluvia puedas captar.

¿Cuánta agua gasta una casa a la semana en México?

Para mi familia de cuatro en Chiapas, lo que de verdad necesitamos de agua de lluvia va de unos 1,000 litros a la semana cuando somos frugales — dos regaderazos rápidos cada quien y excusados de descarga reducida, sin lavar ropa — hasta unos 2,000 cuando lavamos ropa seguido, que por mucho es la tarea que más agua consume. Un baño composta te dejaría bañarte más seguido y aun así quedar cerca de la cifra baja. Tu propio número depende más de las regaderas, la lavandería y el tipo de excusado que de cualquier otra cosa.

¿Qué tan grande debe ser una cisterna para vivir de agua de lluvia?

La mía tiene unos 10,000 litros y ha sostenido a una familia de cuatro (usando entre 1,000 y 2,000 litros a la semana, según la lavandería) durante las temporadas secas. Si la volviera a colar, iría a 12,000–15,000 litros para tener más margen. Dimensiónala contra tu tramo seco más largo, no contra un día de lluvia fuerte — y recuerda que es la única parte que no puedes agrandar fácilmente después.

¿Cómo se filtra el agua de lluvia para una casa?

Filtro tosco primero, fino después: un tambo lleno de piedra en la captación para mantener el flujo alto durante un aguacero, luego el filtro en línea del tinaco Rotoplas, y después filtros de regadera baratos y un filtro de cocina para el agua que se bebe. Un filtro fino en la captación simplemente se tapa con un aguacero. Para agua de beber en específico, fíltrala y analízala bien — que sepa limpia no es lo mismo que esté comprobada como segura.

¿El agua de lluvia de un techo de lámina es más limpia que la de uno de concreto?

En mi experiencia, claramente sí. El agua que escurre de mi techo de lámina es más limpia que la del techo de concreto, así que alimento la cisterna (y la casa) con el techo de lámina, y mando el agua del techo de concreto a un tanque aparte para lavar ropa. El material del techo y el agua que puedes captar son decisiones que van juntas.

¿Necesito permiso para un sistema de agua fuera de la red?

Captar agua de lluvia es una cosa; perforar un pozo profundo es otra — como residente extranjero entendí que necesitaba confirmar el permiso antes de perforar, y el agua está regulada. El manejo de aguas residuales también está sujeto a reglas. Yo trataría todo esto como algo que hay que confirmar con un abogado o la autoridad correspondiente para tu propio terreno, en lugar de suponer — estoy describiendo mi instalación, no la ley.

Related: Water system for a house in Mexico · Tin roof vs concrete roof in Mexico · Buying land in Mexico as a foreigner · All the building guides

The honest version

I’m not an off-grid purist — this is about resilience

Let me be honest about what this is and isn’t. I’m not living a zero-impact dream. I have flush toilets — I broke the off-grid rule about composting — though I fitted the smallest tank I could find and dropped a 600 ml bottle inside it, which brings each flush down to about 3.1 litres. I run a pump on grid electricity. This isn’t ideology; it’s a house with no water connection, made to work on what falls on the roof.

I spent years on international-development work in rural Guatemala — at one point as an innovation specialist, where I tested a rainwater-storage bag from Africa that sat under a roof like a small tent. Supplying my own family needed something far more robust than that bag, and an off-grid water system is what I settled on.

The real constraint

The real problem with rainwater isn’t catching it

If you’re planning rainwater harvesting in Mexico, the first thing to learn is that catching the rain is the easy part. Before I built anything, I thought rainwater was mostly about collection — point the roof at a barrel and you’re done. Three things turned out to be the real challenge, and only one of them is easy.

The three challenges of rainwater

The third row is the whole game. My tin roof — the one that supplies the house — is about 50 m² (5 × 10 m), and on the heaviest days I can catch up to 5,000 litres from it in a single day. That takes a real tropical storm, though: a millimetre of rain on a square metre is a litre, so 5,000 litres off 50 m² means around 100 mm of rain in a day — which only happens a handful of times a year. After the rains end around mid-November, you’re living on what you stored through October and November, with only a handful of light, infrequent showers until the next wet season arrives in May or June. That long dry stretch is exactly why the first real decision is storage.

Storage

Start with storage — it’s the one thing you can’t redo

Almost everything in an off-grid water system can be adjusted later. The cistern can’t. It’s poured concrete in the ground, and you live with the size you chose.

Mine is a concrete-lined cisterna holding about 10,000 litres. It works — it has carried a family of four through the dry seasons. But if I were pouring it again I’d go to 12,000–15,000 litres, because the storage is what bridges the gap between the months it pours and the months it doesn’t. Once it’s set, enlarging it means breaking concrete. The build itself — what it cost, how it’s lined — sits in the water system guide alongside the pump and roof tank; here the point is simpler: err bigger. Storage is the cheapest insurance against a long dry season, and the hardest thing to add afterwards.

Filtering

The mistake is filtering rainwater too finely, too soon

This is the counterintuitive part: at the point of catchment I filter less, not more. A fine filter is exactly the wrong thing when 5,000 litres wants through in an afternoon — it clogs, backs up, and the rain you were trying to catch runs off the edge.

So my first-stage filter is deliberately crude: a 50-litre drum with large stones (4–6 inches) at the bottom and smaller ones (around 2 inches) above. No fine media, nothing that chokes the flow. It takes out the leaves and grit and lets the volume through. The cleaning then happens further along the chain, where it doesn’t have to keep up with a downpour:

Catch fast and dirty. Clean slowly and often.

The quality surprised me. The water leaves no hard-water scale in the showers, sinks or toilets, and to my taste it’s cleaner than the town supply — I’d rather drink it than rely entirely on refilled garrafones. But I’ll be straight: taste isn’t a safety test. I drink mine — mostly as tea, so it’s boiled — and I’ve had no problems, but that’s my experience in my house, not advice. Roof runoff can carry bacteria and whatever’s on your roof. If you’re drinking rainwater, filter and test it properly, and treat the well-permit and water-quality side as something to confirm with someone qualified for your own site.

Roof routing

Which roof’s water goes where

Not all rainwater is equal, and the roof it comes off decides what it’s good for. Water from my lámina (tin) roof is noticeably cleaner than runoff from the concrete roof — so I route them to different jobs rather than mixing them.

Water by roof — each source to its job

This is one more reason the roof decision and the water decision are tied together — the material you put overhead changes the water you can collect under it. I get into the wider trade-off in tin roof vs concrete roof in Mexico. It’s also why, if your land has no connection, the roof and the catchment should be planned together from the start, not stitched together afterwards — the same point I make about buying land in Mexico with no water on it.

Overflow

Planning for too much water

The flip side of catching 5,000 litres in a day is that, in the wet season, you have far more than you can store or use — and water you don’t direct deliberately ends up where you don’t want it. The tin roof fills the main cistern; my concrete roof and the French drain can deliver roughly as much again, but the tanks they feed are small — a 1,000- and a 500-litre Rotoplas — so on a big storm day most of that second stream just overflows. A diversion pipe sends the excess out to the street once the tanks are full. So part of an off-grid setup is routing the overflow on purpose — and accepting you’ll lose the rest.

My approach is low-tech and cheap. I run PVC tubing with taps at the junctions so I can switch the flow different ways — diverting it into a buried garden barrel, for instance, to keep water for the plants and animals. On a slope, French drains do the same job for ground runoff: they feed the same storage rather than letting the water cut channels across your land.

What I’d change

What I’d do differently

I’d pour a bigger cistern — 12,000 to 15,000 litres — because storage is what carries you through the dry season and it’s the one thing you can’t enlarge later. I’d plan the catchment and the roof together rather than treating collection as something to add once the house was up. And I’d accept sooner that the easy-sounding part (catching rain) is trivial next to the parts nobody pictures: storing it, routing the excess, and dealing with what leaves the house.

Low-water living

What low-water living actually feels like

People imagine off-grid water means hardship. Mostly it means attention — and there isn’t a single number, there’s a range. Where you land in it comes down mostly to two choices: how you wash clothes, and what kind of toilet you have.

Water use per week — where you land in the range

The biggest swing is laundry — washing clothes is genuinely water-intensive, and it’s most of the gap between those columns. Toilets are the other lever: mine are conventional flush cut to about 3.1 litres, but compost toilets would buy back enough to shower more often and still sit near the frugal end. Either way, one thing worth knowing: washing dishes can use as much water as a shower depending on your taps and how you do it, so the savings often hide in the ordinary jobs rather than the obvious ones.

What you gain in exchange is independence and, honestly, better water — soft, scale-free, and not trucked in. What you give up is the ability to forget about it. You watch the cistern through the dry months the way other people watch a fuel gauge. After a few years it’s just a rhythm, not a chore.

The rain is the easy part. Everything that decides whether you have water in April happens before the first drop falls.

FAQ

Common questions

Can you really run a house on rainwater in Mexico?

On my plot in Chiapas, yes — with no mains connection, rainwater off the roofs is my main supply, stored in a 10,000-litre cistern and pumped to a roof tank. Whether it works for you comes down to your rainfall, roof area, storage size and how long your dry season runs. The limiting factor is almost always storage, not how much rain you can catch.

How much water does a house use per week in Mexico?

For my household of four in Chiapas, how much rainwater we actually need runs from about 1,000 litres a week when we’re frugal — two quick showers each and reduced-flush toilets, before any clothes washing — up to around 2,000 once we’re regularly washing clothes, which is by far the most water-intensive job. Compost toilets would let you shower more often and still sit near the lower figure. Your own number depends on showers, laundry and toilet type more than anything else.

How big a cistern do you need to live on rainwater?

Mine holds about 10,000 litres and has carried a family of four (using roughly 1,000–2,000 litres a week, depending on laundry) through the dry seasons. If I were pouring it again I’d go to 12,000–15,000 litres for more margin. Size it against your longest dry stretch, not against a heavy day of rain — and remember it’s the one part you can’t easily enlarge afterwards.

How do you filter rainwater for a house?

I filter crude-first, fine-later: a stone-filled drum at the catchment to keep the flow rate high in heavy rain, then the inline filter on the Rotoplas roof tank, then cheap shower filters and a kitchen filter for drinking. A fine filter at the catchment just clogs in a downpour. For drinking water specifically, filter and test it properly — clean-tasting isn’t the same as tested-safe.

Is rainwater off a tin roof cleaner than off concrete?

In my experience, clearly yes. Runoff from my tin (lámina) roof is cleaner than off the concrete roof, so I feed the cistern (and the house) from the tin roof and send concrete-roof water to a separate tank for washing clothes. The roof material and the water you can collect are linked decisions.

Do I need a permit for an off-grid water system?

Rainwater catchment is one thing; drilling a deep well (pozo profundo) is another — as a foreign resident I understood I needed to confirm permission before drilling, and water is regulated. Wastewater handling is also subject to rules. I’d treat all of this as something to confirm with a lawyer or the relevant authority for your own site rather than assume — in Mexico, water is regulated federally through CONAGUA. I’m describing my setup, not the law.

Related: Cost to build a house in Mexico · Buying land in Mexico as a foreigner · Tin roof vs concrete roof in Mexico · All the building guides

That last point matters, because the two big numbers on this page are close enough to confuse. The ≈MX$74,000 is the system inside the house — cistern, pump, roof tank, pipes, fittings, boiler connections and wastewater. Getting water out of the ground in the first place, if your land has none, was a separate ~MX$80,000 quote. Don’t let them blur together.

Plan water first

Water wasn’t a finishing detail

Most masons here build the shell first and think about plumbing and lighting later — if you let them. That isn’t laziness; it’s just how the work is sequenced. The trouble is that if you’re waiting for the mason to raise pipe routing, drainage, bathroom layout or boiler placement with you, the conversation often doesn’t happen until it’s too late to do it well.

Self-managing means getting ahead of it. The shell goes up fast — foundations, columns, cadenas, blockwork, roof, render — but the things that make a house comfortable are hidden inside that shell. Pipe runs, waste falls, shower and toilet positions, the kitchen route, the roof-tank feed: all of it has to be thought through before it disappears into a wall or a floor.

That’s the part I underestimated. I was treating water as a later installation. In reality it had already shaped the land, the roof, the cistern, the plumbing layout, the drainage and the budget. The cost breakdown on this site gives water one line — this page is the story behind that line.

Well or rain

If your land has no water — well, rainwater, or both

My land came with no water connection at all. That’s common on the rustic plots foreigners are drawn to, and it’s exactly the kind of thing that makes “cheap” land less cheap than it looks. With no connection, you have two real sources: catch rain, or get water out of the ground — and sometimes both.

A well sounds simple until you know your water table. Mine sits about 18 metres down, which rules out the cheaper hand-dug, masonry-lined well — at that depth you’re into a pozo profundo, a deep drilled well. A local company quoted me around MX$80,000 to drill the bore (these are narrow, about 20 cm wide), drop in a pump, and connect it to the house. The quote assumed a standard depth of around 25 metres; the idea is to drill several metres past the water table to improve the chance of supply through the dry season, and if they have to go deeper there’s an added cost per metre.

The legal side matters too. My understanding as a foreign resident was that I needed to confirm permission before drilling a deep well — but water is regulated and the details are technical, so treat that as a flag to check with a lawyer or the relevant authority for your own situation, not as settled fact. In Mexico, groundwater is regulated federally through CONAGUA — that’s the official starting point, not this page.

Rain was the other half of my answer, and the roof you build decides how useful it is. Water off my lámina (tin) roof is much cleaner than runoff from the concrete roof, so the metal roof feeds the cistern that supplies the house while concrete-roof water goes to a separate tank for washing clothes. That’s my setup, not a universal rule, and it’s one reason the roof decision and the water decision are tied together — I get into why in tin roof vs concrete roof in Mexico. The full catchment build — gutters, filtering, overflow, dry-season storage — is a project in its own right, and I’ve kept it for the off-grid water guide so this page stays about getting water into and through the house.

Storage

The cistern: the part I couldn’t easily change later

Almost everything else in this system can be adjusted, repaired or swapped later. The cistern can’t — it’s poured concrete in the ground, and you live with the size you chose.

Mine is a concrete-lined cisterna holding about 10,000 litres, and it cost MX$30,000 (roughly MX$20,000 labour and MX$10,000 materials). It works. But if I were pouring it again I’d go bigger — 12,000 to 15,000 litres — because storage is the thing that carries you through the dry months, and once it’s in the ground you don’t get a second chance without breaking concrete.

To size yours, it helps to know what you actually use. My family of four gets through somewhere between about 1,000 litres a week when we’re frugal — two quick showers each, reduced-flush toilets, before any laundry — and nearer 2,000 once we’re regularly washing clothes, which is by far the most water-intensive job. My toilets have the smallest tank I could find, cut down further with a 600 ml bottle so each flush is about 3.1 litres; washing dishes, for what it’s worth, can use as much as a shower. None of that is a rule for your household — it’s just the arithmetic behind why 10,000 litres has been enough for us, and why I’d still pour bigger if I could.

Pump & gravity

Pump to roof tank, then gravity feed

The system itself is simple, which is the point. A pump lifts water from the cistern up to a 1,100-litre Rotoplas tank on the roof, and from there it feeds the kitchen, both bathrooms and the boiler by gravity. No pressure pump running every time you open a tap, nothing complicated to fail — just water falling downhill the way it wants to.

The pump matters more than it looks. Mine cost around MX$3,000, but there are two types and the right one depends on the lift between your cistern and your roof tank — the height the water has to climb — so don’t just buy the cheapest box on the shelf. The Rotoplas tank itself was MX$3,800, the pipework and labour to connect the pump up to it came to MX$10,000, and the run from the roof tank down to the kitchen, two bathrooms and boiler was MX$12,000. The Rotoplas comes with an inline filter that gives the water a pass on its way up, which helps if you’re feeding it from rainwater — though it isn’t a full drinking-water filter, just one link in the chain.

And that’s the useful way to picture the whole thing — as one chain: source → storage → pump → roof tank → fixtures → wastewater. A weak point anywhere along it shows up in the finished house.

Plumbing layout

Plan the plumbing before the walls close up

This is where self-managing earns its keep, because once the render goes on, your pipe routes are decided forever. Fixture positions, supply lines, waste lines, boiler placement, access for future repairs — all of it has to be walked through before the walls are finished, and if you don’t drive that conversation it won’t happen. Get it wrong and you live with the consequences: bad smells from a poorly fallen waste pipe, or the daily annoyances that come from nobody having thought a room through.

One of my better-remembered arguments on the whole build was over moving a half-built wall a few inches — it was maybe three feet tall and rising fast — because as it stood, the back of the toilet wouldn’t align with the bathroom wall and its plumbing. We moved it. Precious memories.

How much of this you chase yourself depends on how you run the build — architect, maestro de obra, or doing it all yourself. But the lesson is the same either way: walk the water and waste routes before they’re hidden.

From my build · bathroom pipework

CPVC vs TuboPlus

CPVC vs TuboPlus: where each one made sense in my house

For the supply pipes carrying water to your bathrooms and kitchen, you’re choosing between two materials, and the obvious instinct — buy the tougher one everywhere — is the one I’d argue against.

CPVC is cut with a saw and joined with a yellow glue. It’s what masons reach for when they install the plumbing themselves: cheap, and genuinely easy to work with. TuboPlus is the plumber’s choice — heat-fused at every joint, tougher and flexible, with UV resistance CPVC doesn’t have. It also needs a fusion tool that’s bulky at the business end and awkward in tight spaces, and it costs noticeably more.

CPVC vs TuboPlus — where each earns its place

I have both in my house, and here’s the verdict the price tag hides. On the roof and any exposed run I’d use TuboPlus without hesitation — the UV resistance alone settles it, and that’s where pipe failure is a real nuisance. But inside the walls I’m relaxed about CPVC, and not because I’m cutting corners. In my experience the wall runs are the lowest-worry part of the system, and on the day a joint does need opening up, I’d far rather be chasing out a cheap glued joint I can cut and re-stick than a fused TuboPlus run. The cheaper pipe is the more repairable pipe, and inside a wall repairability is worth more than toughness. You’ll see CPVC up on roofs sometimes — usually where a mason handled the plumbing rather than a dedicated plumber — and that’s exactly where I wouldn’t accept it.

Drainage

Wastewater and drainage: the angle matters

Water coming into the house is only half the problem. Water also has to leave properly.

I watched the masons on the plot next door install a rainwater drainpipe, then watched the water sit in it during the next downpour instead of running away. That was the moment I understood that the fall on a pipe isn’t something you can take for granted here — calculating gradient isn’t a universal habit on a building site. Waste pipes get laid “downhill,” yes, but often at whatever slope happens. So I went back and checked my own runs while they were still uncovered and I could get at them, and I taught myself to cut and glue PVC to fix the ones that were wrong.

From my build · waste runs before the slab

The fall I was working to was about 2% — that’s the figure I used and it served me well, but treat it as the working rule I went by, not plumbing code for your site. The wider lesson is the one that matters: check the fall on your drainage before anyone covers those pipes. Afterwards is too late. (The wastewater filtration system I built is a separate project, and it’s in the off-grid water guide rather than here.)

Doing it myself

The plumbing I taught myself

Fusing TuboPlus was the one job I assumed I’d never attempt — the heating tool looked like specialist territory. Then I was installing my kitchen sink, called a friend to help with a new connection, and instead of coming over he lent me his fusion tool. I watched a YouTube video, had a go with no real idea what I was doing, and it worked. You can buy a Chinese TuboPlus heater on Amazon for about MX$400 and practise on offcuts for almost nothing.

A plumber charges somewhere around MX$4,000 a bathroom, more if there are roof connections to bring water down — so if you’re willing to take some of the plumbing on yourself, the saving runs to about MX$10,000. I’m not saying everyone should pick up the tool; bad plumbing hidden in a wall causes expensive problems later. But understanding the system well enough to question and inspect the work protects you even when you hire it out. The plumber knows the technique. You’re the one who has to live with the layout.

What I’d change

What I’d do differently

I’d plan water before the shell, not after. I’d decide between a well, rainwater, or both early, because each one changes the budget, the roof and the cistern. I’d pour a bigger cistern than I thought I needed — mine works, but 12,000 to 15,000 litres would give more margin. I’d walk every bathroom and kitchen pipe route before the walls closed up — toilet and sink positions, shower drains, hot and cold routes, boiler placement, repair access — and I’d check the fall on the drainage before anyone covered it.

Most of all, I’d price the whole thing as one system rather than a string of separate jobs: source → storage → pump → roof tank → fixtures → waste.

Water rewards the planning you do before it’s anywhere on site.

FAQ

Common questions

How much does a water system cost for a house in Mexico?

On my self-managed build in Chiapas, with costs in 2026 pesos, the water system inside the house came to about MX$74,000 — cistern, pump, roof tank, plumbing, boiler connections, wastewater and fittings. That excludes getting water onto the land in the first place; if you need a deep well, budget that separately.

How much does a deep well (pozo profundo) cost in Mexico?

I was quoted around MX$80,000 for a deep well on my plot — drilling the bore, dropping in a pump, and connecting it to the house — based on a standard depth of about 25 metres, with an added cost per metre if they have to go deeper. As a foreign resident, confirm whether you need a permit before drilling.

What size cistern do you need for a house in Mexico?

Mine holds about 10,000 litres and has been enough for a family of four using somewhere between about 1,000 litres a week (frugal, before laundry) and 2,000 with regular clothes washing. If I were pouring it again I’d go to 12,000–15,000 litres for more margin through the dry season — it’s the one part you can’t easily enlarge later.

Is rainwater enough for a house in Mexico?

It depends on your climate, roof area, storage and dry-season length. In my build, rainwater is a major source — the tin roof feeds the cistern — but how much it can carry you comes down to storage and the catchment setup, which deserve their own guide.

Should I use CPVC or TuboPlus?

I wouldn’t use one material everywhere. I’d choose TuboPlus for roof and exposed runs, for its toughness and UV resistance, and I’m relaxed about CPVC inside walls because it’s cheaper, simpler and easier to repair if a joint ever fails.

Related: Who should run your build — architect, maestro or yourself? · Managing your own house build · All the building guides

Can foreigners buy

Can a foreigner buy land in Mexico?

Yes — but the structure depends on where the land is and what legal status it has. Outside the restricted zone — roughly 50 km from the coast and 100 km from a border — a foreigner can generally buy property directly in their own name, with the correct SRE process and a proper deed. That was my situation: titled land in the interior of Chiapas. Inside the restricted zone, along the coasts and borders, the process is different — foreigners normally use a fideicomiso (bank trust) rather than direct ownership. I didn’t go through that, so I won’t pretend to explain it from experience; if you’re buying near a coast or border, find a notary who specialises in it.

But the restricted zone isn’t the trap most people fall into inland. The bigger one is the legal status of the land itself.

The deed

The real question: does the land have an escritura pública?

In Mexico, land is often sold without a registered deed. That doesn’t automatically mean a scam — but it means you need to slow down. The question isn’t “is someone selling this land?” It’s “can this land legally be registered in my name?” That’s the difference between buying property and buying uncertainty.

A proper escritura pública is the document that matters: it shows the land has legal title and can be registered through the public property system. Without it you may have a contract, a receipt, or an agreement with a seller — but not necessarily ownership that protects you later. Having the land’s legal status checked before I bought was one of the most important parts of the whole process.

Types of land

The three kinds of land — and which I’d walk away from

If I were buying again, I’d sort every plot into one of three categories before doing anything else.

Ejido warning

Why you should not buy ejido land as a foreigner

This is the most important part, so I’ll be blunt, then tell you to confirm it yourself — because it matters that much.

Ejido land is communal agricultural land, held by a community of ejidatarios who have use rights under Mexico’s agrarian system. It’s tempting: cheaper than titled land, usually outside the towns, often exactly the space-and-nature plot a foreigner wants. Around San Cristóbal, many foreigners have put money into ejido land.

Here is the problem. If land is still ejido land, there is no normal private deed to register in your name. You may be able to pay someone, build, and live there for years — but you are not holding ordinary private property title. You’d be depending on informal arrangements and the goodwill of a community whose decisions can change. If the Ejido Assembly changes its members or simply changes its mind about who lives there, you could lose your home and have little or no practical legal route to recover what you paid.

I’m being careful with my wording because the consequences are so severe: this is my understanding as someone who bought land here and watched others navigate it, not legal advice, and the rules are technical.

There is a legal process (you’ll hear regularización or dominio pleno) that can convert ejido land into registrable private property. But most of the cheap “ejido” plots being sold have not completed that conversion. Until it’s done and there’s a real, registrable title, treat it as land you cannot own. And if someone discourages you from checking — that is your answer.

How to check

How to check land before buying in Mexico

The one check that matters most is whether the land can be legally registered in your name. In practice that means verifying the escritura pública, the current legal owner, the boundaries, the registry status, any debts or liens, and whether the land is private, ejido, communal or conservation. A good lawyer or notary does this as a matter of course. If there’s any chance of agrarian status, the Registro Agrario Nacional (National Agrarian Registry) is the place to confirm it; for private property, the local Registro Público de la Propiedad (Public Registry of Property). I wouldn’t rely on the seller’s word, the seller’s lawyer, or a neighbour saying “everyone does it.” For a foreigner putting savings into a build, the cost of checking is tiny next to the cost of buying land you don’t truly own.

Finding land

How I found my land

People assume you find land through an agent. You can, but it’s only one route — and not how I did it. In San Cristóbal there are roughly four ways.

Facebook is the main local marketplace in Mexico for almost anything, land included; local groups, including the San Cristóbal international-community ones, regularly post rustic plots. Established agencies like Remax and Century 21 have a real presence in Chiapas and feel familiar if you’re used to formal listings. Independent local agents advertise some plots online but rely heavily on their own “Se Vende” signs near the land; they’ll show you a plot but usually aren’t part of the legal sale — you deal directly with the owner, who pays the agent a commission behind the scenes. And the most old-fashioned route, which is how I found mine: a hand-painted “Se Vende” sign nailed to a fence near the property. Selling directly to avoid an intermediary is very common here — after I bought, the seller even offered me a commission if I found a buyer for a neighbouring plot. That’s how direct the market can be.

The actual plot

However you find it, the rule is the same: finding the land isn’t the hard part. Verifying it is.

Scout the area

Spend time in the area before you buy

Don’t visit a plot once, fall for the view, and start imagining the house. Talk to people already living nearby — about water, access, electricity, transport, humidity, security, and whether land in that area normally has proper deeds. Make a list of non-negotiables before you start looking. Mine included distance: I knew I didn’t want to depend on cycling downtown every day, and I wanted cleaner air than the centre of town. I bought a small PM2.5 air-quality sensor, and it confirmed what I suspected — particle pollution is high in many Mexican towns, around traffic, dust and wood smoke, and much lower a couple of miles out.

The surprise was humidity. In the rainy season my indoor humidity runs higher out here than it would in town — which matters for comfort, mould, storage and materials. A plot isn’t just a price per square metre; it’s a microclimate, a water decision, and a transport decision all at once.

Land prices

How much does land cost near San Cristóbal?

As a rough local reference: on the outskirts with basic services, around MX$3,000/m²; closer to markets and more desirable areas, up to about MX$5,000/m². Those aren’t official prices — they move with location, access, slope, services, water, legal status and year — so treat them as a starting point, not a market rate. And be careful comparing a “cheap” rustic plot against titled land: once you account for missing water, deeds, access or build permission, the cheap one often isn’t.

Subdivision

Buying part of a plot: subdivision is possible

Worth knowing even if you don’t expect to need it: land can sometimes be subdivided as part of the purchase. In my case the seller let me buy half of a larger lot, which meant the land had to be legally divided and registered — handled at the same time as the purchase. I didn’t get an isolated figure for it (it sat inside larger bills); I’d estimate it at roughly MX$10,000 in 2017, but the real point isn’t the number — it’s that subdivision is an option, and one many buyers don’t realise exists. If you’re buying part of a property, don’t treat a fence line or the seller’s description as enough; you need to know the subdivision can be legally done and registered. The same goes in reverse — adjacent plots can sometimes be combined into one legal property (I built across two, so combining made sense). Handle it through the lawyer as part of the purchase, never informally.

Co-ownership

Co-ownership: a usufructo vitalicio for my children

Adding it at the time of purchase also kept the cost down: the paperwork it relied on — the land appraisal, the registry work — was already being done as part of the purchase, so I didn’t pay for any of it twice. What it added was the notary’s fee and the transfer tax for the children’s share, which together came to under MX$10,000 in 2017. Arranged separately later, the same protection would have meant paying appraisal and registry costs all over again. And there’s a quieter saving underneath that, as I understand it: everything was calculated on the value of raw land, before any house existed. The house I built afterwards simply became part of land my children already co-owned — not a separate asset that would one day need transferring to them at house prices. Confirm how that works for your own case with the notary; this is exactly what they’re for.

So if you’re buying land here and have children or long-term family considerations, raise it with your notary at the start of the purchase, not after — ask directly about ownership structure, usufructo and inheritance. I wouldn’t assume my arrangement is right for everyone — nationality, tax, marriage, inheritance and future plans all matter — but don’t leave that conversation for later.

No water

If the land has no water

Land doesn’t always come with a water connection. Mine didn’t — and that changes the real cost of a plot. Your options may be rainwater catchment, trucked water, a local connection, or a well. In my area a drilled deep well (pozo profundo) was quoted at around MX$80,000 to drill, pipe, fit a pump and connect to the house, based on a depth of about 25 metres with extra cost per metre beyond. Before assuming you can drill, check the requirements: water is regulated, wells may need permission, and as a foreign resident you should have your lawyer confirm exactly what permit you need for your situation before spending. I cover the full water system — cistern, pump, gravity feed and plumbing — in water system for a house in Mexico, but for land buying the point is simple: no water isn’t a detail, it’s one of the biggest factors in whether a plot is actually affordable.

If you do end up relying on rainwater, the roof you build matters more than you’d think — the material changes how clean the captured water is. I get into that in tin roof vs concrete roof in Mexico.

Final advice

What I’d tell another foreigner buying land here

Spend time in the area first. Decide your non-negotiables before you fall for a plot. Then slow down before paying — because the most dangerous moment is when the land feels perfect and you want the deal to be true. That’s exactly when you need to become boring: ask for the deed, ask who owns it, ask whether it’s private property, ask whether it was ever ejido land, ask whether it can be registered in your name. Ask your own lawyer, not the seller’s. Ask the notary. Ask the registry.

If the land has a clear escritura pública and your own independent professional confirms it can be registered in your name, you’re dealing with something solid. If it has no deed, or is still ejido, communal or conservation land, understand what that means before you pay: you may be buying a hope, a promise, or an informal right to occupy — not ownership.

Buy the deed. Or know exactly what you’re getting without it.

Why tin

Why I chose tin in the first place

By the time the walls were up and the house was taking shape, I’d relaxed into managing the build and started enjoying the parts where I could improvise. The roof was one of those decisions. I wanted to put an exposed industrial-style metal frame inside the house — beams running across the structure — and a tin roof let me do that. It looked the way I wanted, and it had two practical advantages I talked myself into as well.

The first was weight. A tin-and-metal roof is far lighter than a slab of poured concrete sitting on top of your walls. In a region with regular earthquakes, that felt sensible to me as the person managing the build. I wouldn’t treat it as structural advice — the whole building has to be designed properly, walls and beams and foundations together — but I liked the idea of reducing unnecessary weight overhead.

The second advantage was the one I got wrong: I assumed tin would be cheaper. It seemed obvious — no slab to pour, no truckloads of concrete. That assumption is where the lesson is.

The cost

Where the money actually went

From the actual build

The freak accident

The week I thought I’d made the wrong call

A week after the tin roof went on, a neighbour hired someone to clear boulders from their plot with dynamite. The explosions threw rock high into the air, and three pieces came down through my brand-new roof, punching clean holes in it. I was devastated, and for a while it made me question whether I’d chosen wrong.

I want to be clear about this, because it’s easy to draw the wrong lesson: that was bad luck, not a flaw in tin roofs. Falling rock from a dynamite blast would have damaged almost anything, and the holes in tin are, if anything, among the easier things to patch. It felt like a verdict on my decision at the time. It wasn’t. It was just a bad week.

Concrete cracks

The concrete roof is the one that haunts me

Here’s the part that really settled the argument for me. The poured concrete roof — the “proper” one — is the roof I struggle to sleep over. A few months after it was poured, I found large fissures running through it. The likely causes were heat, not keeping the concrete damp enough while it cured, and possibly the slab not being supported well enough during the pour and curing. Whatever the exact mix, the result was a cracked roof and leaks.

I fixed it, and the way I fixed it matters, because my first attempt failed.

Maintenance is the quiet difference the brochures never mention. The concrete roof needs repainting with flexible waterproof paint roughly every four years — around MX$3,000 in paint and labour each time, depending on size — or the cracks come back. The tin roof asks for nothing.

Exposed-ceiling trick

A trick for an exposed concrete ceiling

One advantage of managing your own build is that you can experiment as you progress with the build. Over my dining area, which has a low ceiling, I wanted a smooth, modern grey concrete finish on show rather than something to be plastered over. So I had the mason use plywood as the formwork to pour the ceiling against.

Cleaner water

The bonus I didn’t expect: cleaner water

Because I capture rainwater, the roof material turned out to matter in a way I hadn’t planned for. Water coming off the tin roof is far cleaner than water off the concrete one — concrete is more porous and holds dust, residue and surface grit, while metal sheds water straight off. So I route them differently: the tin roof feeds my cistern, which supplies the bathrooms and kitchen, while the dirtier concrete-roof water goes to a separate tank for washing clothes. How that stored water then gets pumped up and fed to the taps is its own build — I cover it in the water system for a house in Mexico. If you’re going to harvest rainwater, the roof you choose quietly decides how clean that water is — and the catchment, filtering and dry-season storage are their own build, which I cover in off-grid water in Mexico.

One caveat, so nobody takes this too far: cleaner doesn’t mean automatically drinkable. Whether roof water is safe to drink depends on filtration, storage, a first-flush system, animals, and what’s in your local air — not just the roof. What I’m saying is narrower: for capturing cleaner water to store and filter, the metal roof wins clearly.

And if you’re buying land with no water connection at all — as I did — the roof is only half the picture. Whether a plot has water, or needs a well or catchment, is one of the biggest hidden costs in buying land in Mexico as a foreigner.

After every rainy season I’m more sure of it: the roof that cost me more is the one I’d build again, and the cheaper one is the one I have to keep an eye on.

The verdict

So — would I choose tin again?

Yes, without much hesitation — but not because it’s cheaper, because it usually won’t be once you account for the frame. I’d choose it for what it gives back afterwards: no cracks, no porousness, no maintenance, cleaner captured water, less weight on the walls in earthquake country, and the sound of rain on a high ceiling, which I find genuinely lovely even on the nights it’s loud enough to bury the television. The concrete roof was meant to be the safe, solid choice. In practice it’s the one that cracked, the one I repaint, and the one I think about when it rains hard. The tin one just sits there and does its job.

There’s one case where I’d still pick concrete, though: if you might build another storey on top later, a poured slab gives you a floor to build on, and tin doesn’t. If there’s any chance of going up a level down the line, that can outweigh everything above.

What I’d change

What I’d do differently

Two things, both about deciding earlier. I’d make the roof decision sooner, and I’d think about rainwater catchment before the walls were finished rather than carrying it vaguely in the back of my mind. Where the water drains, where the gutters go, how the slope works, how the water reaches the cistern — all of that is easier to get right while the structure is still open than to retrofit afterwards.

And I’d price the roof as a whole system, not as sheets of lámina. The real cost isn’t the covering — it’s the beams, the welding, the wood underneath, the paint, the labour, the gutters, the drainage, and the waterproofing if you go concrete. Adding all of that up in advance is what would have saved me the surprise of the “cheap” roof turning out to be the expensive one. That’s the part I underestimated, and it’s the single thing I’d tell anyone starting out.

Also in the building series