Building in Mexico · what I learned
Water was the part of my Mexico house build I should have planned first
I treated water as something I’d sort out once the house was standing. That was the mistake — by the time I was thinking seriously about cisterns, roof tanks and pipe routes, the walls were going up and some of my choices had already been made for me.
Why it matters
Water isn’t a finishing detail here. It decides whether the land you bought was actually cheap, whether your roof is any use for catching rain, how much storage you need before the rest of the house works, and where every pipe has to sit before the render closes the walls. If I built again, water is one of the first systems I’d plan, not one of the last.
The basis
This guide to the water system for a house in Mexico is based on one self-managed build in San Cristóbal de las Casas, Chiapas — my figures, my mistakes, and the parts I taught myself. It isn’t a professional plumbing design, a legal guide or a well-drilling manual.
My water system at a glance
Cistern → pump → 1,100 L Rotoplas roof tank → gravity feed → kitchen / 2 bathrooms / boiler
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
First-hand · a small thing that looked harder than it was
Fitting a toilet
I’d always assumed a toilet involved some elaborate installation. It doesn’t. I bought mine with no plumber on site, read the manual, and found the basic job is two holes drilled in the floor and a flange that seals the pan to the drain. Flanges run from about MX$40 to MX$600; the cheap wax one gives a good airtight seal if your floor is level, and I never saw a reason to buy the pricier plastic kind. A bead of silicone around the base finishes it — I used Sika sealant, easy to find on Amazon Mexico. Some of this work looks more intimidating than it is.
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
| CPVC | TuboPlus | |
|---|---|---|
| Per wet room | ~MX$150 — in-room runs | ~MX$600 — in-room runs |
| Connections up to the roof | ~MX$700 | ~MX$2,500 |
| How it joins | Cut and glue | Heat-fused |
| Strengths | Cheap, simple, easy to repair | Tough, flexible, UV-resistant |
| Weaknesses | Less robust; relies on the glue joint | Dearer; needs a fusion tool; awkward in tight spots |
| Where I’d use it | Inside walls and floors | Roof runs and exposed/UV-exposed pipe |
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.)
Costs
What my plumber installed, and what it cost
These are the cost items I used for the water and plumbing side of my own build budget — a mix of paid figures and practical estimates from my two-bed, two-bath house in Chiapas, in pesos. Treat them as a structure to adapt rather than a quote: plumbers bundle labour and materials differently, and wastewater in particular swings a lot with your house’s layout. Everything here is the system inside the house — the deep well is separate.
Cost breakdown — the house water system
| Item | Cost | |
|---|---|---|
| Cistern, ~10,000 L concrete-lined | MX$30,000 | ✓ |
| PumpTwo types; size it to the cistern-to-roof lift | ~MX$3,000 | ~ |
| Pump → roof tankMaterials & labour | MX$10,000 | ✓ |
| Roof tank → kitchen, 2 baths & boilerMaterials & labour (TuboPlus) | MX$12,000 | ✓ |
| In-room supply pipework2 baths + kitchen (TuboPlus) | ~MX$1,800 | ~ |
| Wastewater plumbing, whole houseVery design-dependent | ~MX$6,000 | ~ |
| Rooftop tank, 1,100 L Rotoplas | MX$3,800 | ✓ |
| Boiler / water heaterRange MX$1,500–25,000 | ~MX$5,000 | ~ |
| Boiler connections + 2 shower valves | MX$2,089 | ✓ |
| Water & plumbing system | ≈ MX$74,000 |
A note on the pipe lines: the roof-tank run assumes TuboPlus, since it’s exposed. Swap the in-room runs to CPVC and you’d save most of that MX$1,800; do the same on the roof connections and the gap is wider still — MX$700 against MX$2,500 — which is the cost side of the choice above.
And again, this does not include the deep well — that quote was around MX$80,000 on its own. Which is the real reason to price water as a system, not a string of parts: the cistern, pump, tank, pipes, valves, boiler, waste lines and labour all arrive close together near the end if you haven’t planned them earlier.
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 this page doesn’t cover
This is the water supply and distribution system — getting water onto the property, stored, pumped, distributed and drained. The off-grid build is a separate body of work, now covered in its own guide:
- The full rainwater-harvesting setup
- Filtering crude-first, fine-later (keeping flow rate up in heavy rain)
- French-drain capture on a slope
- Planning for the days you catch far more than you can use
- The three-stage bathroom wastewater system I built
Read it: off-grid water in Mexico →
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.
Written by Luke Burchell
I self-managed the construction of my own house in San Cristóbal de las Casas, Chiapas, including the cistern, pump, gravity-fed system and the plumbing I learned to do myself. Everything here is from that build: what I paid, what I’d do again, and what I’d plan earlier.