Yucatan Plumbing

Yucatan Plumbing

30 June 2016 Real Estate FYI 21

So you’ve just bought your colonial home in the historical center of Merida, moved in all your furniture and planted a couple bougainvilleas in the patio. You step up to the bathroom sink to wash your hands, but when you turn on the faucet, nothing happens. If you’re like us, your first instinct is to ask your partner if they forgot to pay the water bill. Your next instinct is to call the water company and complain.

But here in the Yucatan, the problem is you have an empty tinaco (tee-NAH-koh).

Newcomers to Merida are usually not prepared for the differences in plomería(plumbing) here in Mexico. Back in the States, the water company generally provides enough pressure to deliver water right to your faucets. This is usually accomplished by pumping the water to a higher elevation and letting gravity do its work.

In Mexico the costs of pumping water through the antiquated water distribution systems in these old cities would increase the price of delivery, and many of the local residents would not be pleased (although the monthly water bill for our house is $70 pesos – less than seven dollars). As for using gravity to deliver the water, everyone here knows that the Yucatan is as flat as a tortilla (the highest elevation is probably the top floor of the Hyatt Hotel downtown). Consequently, the water pressure provided by the city is unreliable at best.

For these reasons and others, houses are equipped with a water storage tank, called a tinaco, located on the roof, usually sitting high on a pedestal. The height of the tinaco and the diameter of the tuberías (pipes) determine how much water pressure you have. In some areas, city water pressure is capable of filling your tinaco. But it’s not wise to rely on it. So a more elaborate plumbing system is designed into most houses. This system is illustrated in the diagram below.

The tinaco is a plastic tank, usually coated inside with an anti-fungal chemical layer. It has a screw-on lid and an inlet on the side near the top and an outlet with a valve coming out the opposite side near the bottom. The most common manufacturer around here is Rotoplas. The standard tinaco holds 1,100 liters (290 gallons) of water and costs about $700 pesos.

As you drain your tinaco, a flotador in the tank detects the falling water level. There are two types of flotador, a mechanical version that operates a valve, much like the kind in your toilet, and an electrical version that closes an internal switch. If your tinaco is receiving water directly from the city water system, the flotador will simply open a valve as the water level falls.

But, as shown in the diagram, most tinacos have an electrical flotador, which is on a rather long leash. When the water level falls to about 1/3 full, the flotador inverts, the switch inside closes and turns on a bomba (pump) somewhere in your house, usually on the ground floor.

The bomba is typically a ½ horsepower pump that draws water up from your cisterna (cistern) and sends it flowing into your tinaco. Your cisterna is always underground somewhere and accessed by a hatch. Often, the cisterna is nothing more than a buried tinaco, but it may be an older and larger construction made of concrete. Once the tinaco is full, the electrical flotador in the tinaco flips back over and turns off the pump. As water is pumped out of your cisterna, the mechanical flotador drops down and opens a valve, which lets the low-pressure city water flow in, keeping the cisterna filled.

There are generally some water sources around the house that are not part of the plumbing system described above. The water for your mangueras (hoses), fountains and irrigation are probably delivered directly from the city water system. This is important to remember, as we will see in a moment. Also, many people with swimming pools fill them from a dedicated pozo (well).

Now that we know how the plumbing around here works, what should be our first move after we turn off the (non-performing) faucet with our dirty hands? Well, use a hose in your backyard to wash up. If water flows out of the hose, then the water company isn’t to blame.

Next, find the bomba that pumps water up to your tinaco. Every homeowner should learn where this and the circuit breaker or switch that powers it are located. You need to know this not only to service the tinaco, but in case a big storm or hurricane blows into town, you’ll want to turn off your system to avoid contamination from the city water that may occur during flooding. Your bomba will most likely be hidden away in a room in the house that’s located below the tinaco.

If the bomba is running, turn it off. Then, “echale un ojo al tinaco” (literally, “throw an eye at the tinaco”, but it means “check the tinaco”). Your house undoubtedly has access to the roof or at least a ladder, so climb up there, unscrew the lid on your tinaco and peer inside.

If there’s water down there, then check the outlet valve and make sure it’s open. If it is, the handle will be going the same direction as the pipe. On the inlet side of the tinaco is (at least) a paso uno filtro (first stage filter), which blocks any sand or small particles that may have traveled up from the cisterna. The plastic case is unscrewed by hand and the paper filter inside is replaced. You should replace this filter every three months. If it hasn’t been replaced regularly, it is probably clogged and inhibiting the flow of water. You can buy these filters at most local tlapalería or ferreteria (words for hardware stores), or even at Home Depot.

If the tinaco is empty, reach in and pull out the electric flotador. If it’s not full of water and you hear a ball bearing rolling back and forth inside, then it’s probably okay. Otherwise, it’s a candidate for replacement as well. We recommend the type of flotador pictured here, which has proven to be very reliable and long lasting.

If none of these issues seem to be the problem, then climb back down and return to the bomba. If you turn on the switch and the bomba doesn’t operate, then you either have a bad flotador, a dead bomba (not likely) or a bad power switch. Call a plomero (plumber). He will be able to solve any of these problems, because here in Yucatan, plumbers are both plumbers and electricians. Handy, no? The most expensive repair among these problems is replacing the bomba. They cost about $650 pesos for a new one, plus a couple hundred pesos for labor.

If the bomba does run when you turn on the switch but no water was in the tinaco, it could mean the pump has failed, but this rarely happens. In our experience, bombas last many years. Much more commonly, the bomba has lost its “prime”, which means there is no water in the pipe coming from the cisterna for the bomba to pump.

Check your cisterna. It’s probably under your patio or in the back yard. Lift up the hatch, unscrew the lid and make sure there’s water inside. If not, the mechanical flotador has seized up. You can usually loosen it with a spritz of WD-40 and a wiggle or two, but if it looks too old and rusty, you might as well replace it.

Note: WD-40 is to the Yucatan what duct tape is to the rest of the world. Always keep a can on hand and don’t be afraid to use it around plumbing. It is non-toxic.

If there’s water in the cisterna, then take a look at the diagram again. You’ll notice a strange little valve at the end of the pipe that descends into the cisterna. This is called the pichancha. Its job is to prevent water from flowing out of the pipe and back into the cisternaso that the pipe and pump will always be full of water. There are several styles of pichanchaand the most common are also the least reliable. We have found that the style shown in the photo, which has a Teflon-coated valve and is available from Boxito or Surpesa for less than $150 pesos, is the best style available here in Merida. A leaky pichancha and loss of prime in the pump is the most common culprit that causes the whole system to fail.

If the system has not been used for a while (which is common in rental or vacation homes), the bomba will lose its prime even with a good pichancha. If you aren’t afraid to use a pipe wrench, you can prime the pump and find out if the problem is caused by a leaky pinchancha or just disuse.

In the diagram, you’ll notice a funny little branch of pipe coming off the pipe that exits the bomba upwards on its way to the tinaco. It is capped and can be unscrewed using a pipe wrench. This is where you prime the bomba. Go fill a container, such as a pitcher or empty two-liter coke bottle, with water from your garden hose. Return to your bomba and SLOWLY unscrew the cap counter-clockwise. If water starts to squirt out, then the pump is already primed, but you probably have a weak or faulty bomba. Tighten the cap, stop here and call a plomero.

But in most cases you’ll find that the pipe is dry as a bone. Slowly pour water into it until it fills. This may take several trips to the garden hose, depending on the size of your container and how much pipe there is between the bomba and the cisterna. Once the pipe is full, let it stand for several minutes. If you poured too fast, there may be air trapped in the pipe that needs to settle. Refill if necessary.

If the pipe never seems to fill, then you have a leaky pichancha. Time to call that plomero unless you really feel like tackling the job yourself.

If the water stands level with the top of the priming pipe for several minutes, then recap the pipe firmly and flip on the switch that powers the bomba.

There are several ways to see if your handiwork has solved the problem. The most obvious is to leave a faucet open and wait a few minutes for water to flow. Another is to climb back up to the tinaco and see if water is flowing into it (which you should do if you forgot to screw the lid back on; always leave the lid of your tinacofirmly in place). Yet another is to check the cisterna to see if the water level is falling. Or you can turn off the pump, SLOWLY unscrew the priming cap and see if water squirts out.

If the procedure for priming the bomba isn’t effective the first time, you may have to repeat it once or twice more to work any trapped air out of the system. If you do not seem to make any progress, or just get exasperated, call a plomero. They are quite capable and very affordable.

There are several enhancements or improvements that many new arrivals to Merida are incorporating into their plumbing systems. One of these is a small, pressure-activated pump that is installed in-line with the output of the tinaco. When a faucet is opened or a toilet is flushed, the drop in pressure turns on the pump and increases the flow. If your tinaco is not located at an elevation high enough for sufficient water pressure, this inexpensive solution may be for you.

Others are installing large-scale electric water pressure systems. These are usually located in an “equipment room” and power a pump that maintains constant water pressure inside a metal tank that feeds the house plumbing. The main disadvantage to these systems is evident during a blackout. Without electricity, there is no water available to the home. Consequently, these systems are always installed with a standard tinaco system as a backup.

Yucatan is notorious for its hard water. The limestone aquifer through which the local water percolates makes it rich in minerals, especially calcium, which we call “scale” but in Spanish is called sarro. The white, crusty deposits clog showerheads, reduce the efficiency of water heaters and ruin washing machines.

Rotoplas, the company that makes the tinacos, offers a stage two filter that consists of a permanent magnet wrapped around a plastic pipe. It is installed in-line after the stage one filter described above. The magnet interferes with the ionic bonding between calcium and other minerals that create scale, thus reducing the deposits. The minerals are still in the water, but the sarro doesn’t have a chance to form. Standard water softening systems that remove the minerals using salt and reverse osmosis are also readily available in Merida.

If you’ve read to the end of this article, we are really surprised. This kind of article is written for a do-it-yourself kind of person, or for those who have a lot of curiosity about how things work. If that’s you, then you’ll be pleased to know that in our next installment, we’ll explain just why you don’t want to flush paper down a Mexican toilet.


  • Lance 6 years ago

    Does the stage two filter really take care of the sarro problem ? Thanks

    • Working Gringa 6 years ago

      In our experience, it does not take care of it completely, but enough to save wear and tear on appliances.

  • Tom 6 years ago

    Thank you for this useful information. Can you give us advice on replacing the plumbing hoses under the sinks in our condo? We do not want to have to replace these hoses every year. We understand the hard water in Mexico corrodes the flexible plumbing hoses annually. Can you recommend a quality plastic pipe or something else that will last longer? Muchas gracias. Tom

    • Working Gringa 6 years ago

      When we built our house, we used CPVC for the plumbing, and it is available as flexible hose as well.

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