Forums > Specific Focus > Home, Garden & Construction in Mexico

talosian

Mar 14, 2006, 4:43 AM

Post #1 of 13 (4249 views)

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Should I add anything to the water in my underground storage tank?

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I read a very educational (for me) 2003 thread here about how the rooftop water systems here work. Am am wondering though about a couple of things.

I live in a Fracc where the water is potable from the tap and pressureized, however in the last newsletter from the Board there was a note about the quality of the Fracc filtration system.

I looked into my underground water reserve and it seems clear though I did notice a lot of "muck" under the lip of the lid and on the ball for the fill valvue. I have an inline filter (a small singel cartridge one) just before the pump and that's it - - - nothing for filtration past that point. To the best of my knowledge, I have never had any problems with the drinkability of my house water.

Should I leave well enough alone or should I add something to the underground water?

Also, I was thinking of shutting off the water from the street and letting the underground tank clear out to inspect and possible repair/clean as needed. Any thoughts here? The tank is about 5-7 years old (built with the house).

Thanks.
"When all logical explanations have failed, we must look to the illogical for the answer.

Rolly / Moderator

Mar 14, 2006, 6:43 AM

Post #2 of 13 (4226 views)

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Re: [talosian] Should I add anything to the water in my underground storage tank?

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My neighbor and I share an underground tank which we drain and clean every couple of years. We do not have a filter, so there is always a layer of sand/muck in the bottom that has settled out of the water. We add some bleach after we have cleaned the tank.

Rolly Pirate

Bubba

Mar 14, 2006, 8:00 AM

Post #3 of 13 (4206 views)

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Re: [Rolly] Should I add anything to the water in my underground storage tank?

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We use a small spa style chlorine floater filled with 1" chlorine tablets we buy at the swimming pool stores. We don't actually drink tap water even though this would make it safe.

(This post was edited by Bubba on Mar 14, 2006, 8:05 AM)

Esteban

Mar 14, 2006, 8:49 AM

Post #4 of 13 (4187 views)

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Re: [talosian] Should I add anything to the water in my underground storage tank?

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There is only ONE way to know if your water is contaminated. Have it tested.

Every situation will be different.

Papirex

Mar 14, 2006, 8:55 AM

Post #5 of 13 (4182 views)

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Re: [talosian] Should I add anything to the water in my underground storage tank?

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There are companies in some areas that will come to your home and clean the underground cisterna and the tinaco on the roof. As part of the cleaning service they usually swab the interior of both reservoirs with chlorine.

The availability of those services probably depends upon where you live. If there is a need for that service where you live, then someone has no doubt started a cleaning service.

We have lived in three houses here in Cuernavaca and we have never had a problem with silting. In the cisterna’s at the first two houses I would see insects in the tank. They looked like small beetles, probably harmless. On a tip from a neighbor, I dropped a chlorine tablet into the cisterna, the insects disappeared.

I wasn’t trying or expecting to make the water potable. I just wanted to get rid of the insects. It did that. I used the chlorine tablets that are sold in Grocery stores that are intended to be used in a toilet tank. The water in the tank was very clear, I could see the tablet lying on the bottom of the cisterna. When it became very small, I would drop another one into the tank, about every 2 ½ to 3 months.

The cisterna capacity in the first house was 10,000 liters, in the second house it was 7,500 liters. Size didn’t seem to matter, one chlorine tablet did the job at both houses.

We have had no water filtration at any of the houses we have lived in here. While I wouldn’t drink it untreated, I think we have a pretty good water supply here. I love our dogs a lot, and they get bottled water to drink just like we do.

Rex
"The supreme happiness of life is the conviction that we are loved" - Victor Hugo

Delia

Mar 14, 2006, 4:51 PM

Post #6 of 13 (4110 views)

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Cleaning aljibes and tinacos

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Never mind a cleaning company, all you need is a plumber.

1ajijic

Mar 15, 2006, 7:18 AM

Post #7 of 13 (4068 views)

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Re: [JohnO] Cleaning aljibes and tinacos

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You probably have at least a foot of gunk in the bottom of your tank. Good luck!
http://www.newbeginningsmexico.com

Papirex

Mar 15, 2006, 8:41 AM

Post #8 of 13 (4053 views)

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Re: [JohnO] Cleaning aljibes and tinacos

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John, I would hope that you are kidding; unfortunately I don’t think you are. Entering a cisterna (aljibe) to clean it would be classified as working in a confined space in The US. It is dangerous and requires special safety training, equipment and annual re-certification in The US to do it legally.

One person should remain outside the confined space to summon help if a worker inside collapses. If the oxygen level in an atmosphere falls below 19%, it will not support life. Doing hard work in an unventilated cisterna would soon deplete the oxygen content of the atmosphere in it.

With only one hatch, there is not going to be any natural air circulation to replenish the atmosphere in a cisterna. Something as simple as a ducted fan could be a lifesaver.

I doubt if the people that clean cisterna’s for a living here have the training and equipment to properly ventilate the work area, but their experience doing it would be a real plus. I would think twice before I sent a Mexican “plumber” in to clean a cisterna.

Just a couple of years ago two men died of asphyxiation while cleaning a cisterna at the Chrysler plant in Mexico City when it was being decommissioned. With the way the laws are structured and enforced in Mexico, I doubt if there were any serious legal ramifications for the employer of the dead workers. I think it would probably be a very different scenario if a foreigner was responsible for sending a worker into a dangerous area to work, and a death resulted.

Workers that die in confined spaces in The US are almost always untrained and do not realize the serious risks involved in working in a confined space. There are a lot of risks and science involved in construction work. The untrained layman is usually unaware of them.

Rex
"The supreme happiness of life is the conviction that we are loved" - Victor Hugo

Bubba

Mar 15, 2006, 2:53 PM

Post #9 of 13 (4018 views)

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Re: [JohnO] Cleaning aljibes and tinacos

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In Chapala Miguel Perales does that type of work and so do the people who sell pool equipment near SuperLake.

Mike McD

Mar 20, 2006, 10:08 AM

Post #10 of 13 (3951 views)

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Re: [talosian] Should I add anything to the water in my underground storage tank?

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Potable water mean water suitable for drinking. But does anyone actually drink the agua potable in Mexico? If not, why not?

The water authority in Querétaro <http://www.ceaqueretaro.gob.mx/> says its water meets international standards.

Yet the Queretanos I've asked drink only bottled water. Mexico is the second largest per-capita consumer of bottled water in the world (behind Italy).

Is this water scare an urban legend? Is there suspicious contaminants entering through the feed lines or through the cistern or roof tank? If that's the case will chlorine kill the contaminants?

Or is this just a preference for better tasting water?

McD

talosian

Mar 20, 2006, 11:56 AM

Post #11 of 13 (3944 views)

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A good/strong fan in the underground tank

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pointed up toward the hatch in an underground holding tank will circulate enough air to clear any issues in a space as small as a household unit. I saw pictures of an underground holding tank at my Fracc (100+ cu mtrs of water) and there were 3-4 men working, with lights and 5 gallon buckets of tar, and with no ventilation and no one died. Just luck most likely.

Just FYI on one specific instance.
"When all logical explanations have failed, we must look to the illogical for the answer.

Papirex

Mar 20, 2006, 12:16 PM

Post #12 of 13 (3942 views)

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Re: [Mike McD] Should I add anything to the water in my underground storage tank?

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Potable is a word that is almost universally mis-applied in Mexico. Cities, states, and even Real Estate agencies will say the water is potable, when what they really mean is that running water is delivered to your house via pipes.

It would be hard to imagine a Mexican politician that would admit that a lot of public money is spent on the water systems, which employ a lot of his relatives and friends, to deliver you water that is not fit for a dog to drink. They will always say the water is potable.

Water quality is very area specific here. A few areas do have very good, safe water. In most areas the quality and safety of the water is an unknown. Having a sample tested only tells you what the condition of the water was on the day it was tested. Having the water tested several times on several different days in different months might give a better indication if the water is safe.

There are so many variables that may allow contamination to occur, it is prudent to assume that all the water is unsafe. Besides the possibility of contamination from almost always-neglected infrastructure, pipelines, etc., your own cisterna (aljibe) or tinaco are potential sources of contamination, unless you have your own water treatment facilities, probably with a chlorinator, on your own property.

I wouldn’t attempt to try to purify water by adding chlorine to it myself. There are just too many variables, and calculations that must be done, and the properties of the water will change every time more water comes into your cisterna.

It is not an urban legend; there is enough unsafe water in some areas to make it a prudent decision to regard all water as unsafe in most areas of the country.

Rex

"The supreme happiness of life is the conviction that we are loved" - Victor Hugo

sfmacaws

Mar 20, 2006, 12:54 PM

Post #13 of 13 (3933 views)

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Re: [RexC] Should I add anything to the water in my underground storage tank?

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Listen to Rex, he is dead on right. Potable is just a figure of speech here in Mexico. There are potable water trucks going up and down our road daily filling the cisterns but the stuff that comes out of them would keep a salt water aquarium going if the bacteria in it didn't kill all the fish. The Municipio says that when we get piped water it will be potable, even if it had a low bacteria count and was technically safe - which I also doubt - no one would drink it because of the level of salts.

Living much of the year in our RV, we do treat our own water in most areas of Mexico. Not here, because of the high salinity, here we just pour bottled water into the tank and filter it for consumption.

We have a known tank capacity and got the amount of chlorine to use from an RV web site. We guessed and used too much the first year and it was like bathing at the old public pools of my youth. Now we measure more carefully and for the first few days there is a whiff of chlorine smell from the water. We also have to wait until the tank is close to empty to refill so the measurements are closer, that usually works well for us as when the fresh water tank is empty, the grey water tank is full.

We have the best water filter we could buy and it filters the remaining bugs and chlorine out for drinking and cooking. We've done this for 5 years with no known ill effects. We have to be aware of it more than people who live in stick houses but that is the same for all systems in an RV, you live closer to the ins and outs of everything you use.

One of the pluses is that I soak fruits and vegetables in the chlorinated water from my tank, no need for other additives. One of the minuses is your hair never feels good after washing it and your skin gets a lot drier. We usually use the last of the water showering before we fill the tank and then wait a day before showering again, chlorine dissipates rather quickly and the effects are a lot less noticeable after a day or two.

We use the same water filtering (we also have an additional filter at the intake to our tank) in the US. If we are using municipal water we don't add chlorine there but if we are filling from well water we do. I think it is silly to drink water straight from the tap anywhere in the world, at the very least you should have some kind of testing that is reliable. I used to get the test results quarterly from the public water in Marin County, Ca. This is an area with high concern for the quality of water and yet there were still problems at times especially in winter when resevoirs overflowed. I always used filters on the water I consumed.

Jonna - Mérida, Yucatán