Water Cisterns

Yachtmaster

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Jul 2, 2007
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Just moved into a two story, three bedroom house in the La Isabelita area of Santo Doming Este. Prior to moving in, we had the tinaco and cistern emptied and cleaned. I understand most water cisterns in SD are hooked up to city water which gets turned on occasionally to fill the cisterns. After several days of waiting and no city water, we had to buy water to be delivered by truck which was not a big deal. 1500 gallons of water cost 1800.00 pesos.

Soon after we filled the cistern with water delivered by truck, we had a good day of rain which poured off the roof through a pipe onto the ground in huge barrel-full quantities. This got me wondering, why do they not direct the rainwater into the cistern as they do in other countries?

How often does the city of SD usually turn on the water supply to the cisterns?

:confused:
 

tommeyers

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Jan 2, 2012
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I live in Santiago
The greatest risk of rain water is microbial the same as DR city water.

I am estimating that I could get 7000 gallons from rain water in a year. 40" avg / mo x 12 months and 350 sq feet collection area. Convert cu feet to gallons.

200$ savings per year?

Did I get that right?
 

Jaime809

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Aug 23, 2012
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Rain water has no microbes, it's as clean as water gets (acid rain aside). The challenge would be making sure any microbes in the container have been killed or eliminated so they don't reproduce to dangerous levels.
 

malko

Campesino !! :)
Jan 12, 2013
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I hope the OP wasnt thinking of drinking it........
I am sure it is just fine for showers ( or no worse than the tap water ) and cleaning amd such......

I collect rain water not for the cistern neither the tinacoa, but for watering garden and conuco.....

@ tommeyers, I pay 150 pesos ( I think, maybe 200 ...), for the mains water ( unreliable and far between bit evem so.....).
So it is not to save money but more to save water.....every bit helps.:classic:
 

pelaut

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Aug 5, 2007
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I have lived off rainwater since 1983 (31 years).

Granted, it was always near the sea and never in a city. The rain-makers came from open sea with hundreds, if not thousands, of miles of fetch to inhabited land. Or they came from mountains that precipitated trade wind moisture that came over thousands of miles of sea, and had been through who knows how many cycles of evaporate/precipitate over the lonely ocean, and the terrain from the mountains to me had no factories or slash&burn agricultores.

Catching "pure" water in Santo Domingo del Este could be possible, I suppose. I need to know a lot more about the specific neighborhood, the roof, the cistern, etc. But blanket "Yaaaaah! Microbes!" for rain water collection is not a worthy sentiment.
 

Olly

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Mar 12, 2007
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Yachtmaster,
Perhaps you remember from your long distance sailing days how to collect rain water to replenish your yachts supplies. The first flush of rain cleans the salt off the sails and should be discarded. The next lot that comes off can be potable and used for drinking. Now that is at sea!
On land it is a bit different as there is not much salt around but there is dust leaves, rat poop , bird poop and the like on the roofs.

We have just designed an eco - friendly water collection system for a large kennels. It incorporates a "First flush filter" that takes about the first 50 gals and discards it, only then allowing rain water to enter the storage cistern or tanaco. The water would be used for cleaning , washing etc but not for drinking. That comes from a well.

With the storage system sized for the typical rainfall and the interval between rain, we think we can supply water for the kennels all year round. They have a huge collection area of 2800 sq ft so an inch of rain produces about 2000 gals.

Interesting project. We will let you know the outcome if it goes ahead and the costs and possible savings. but as someone said it is really about conservation.

On the North Coast between Cabarete and Sosua there is a 20 % deficit in rainfall this year to date based on our figures but today nature is trying to make up for that!!! It is pouring down right now!

Olly and the Team
 

tommeyers

On Vacation!
Jan 2, 2012
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I live in Santiago
Rain water has no microbes, it's as clean as water gets (acid rain aside). The challenge would be making sure any microbes in the container have been killed or eliminated so they don't reproduce to dangerous levels.

Before I wrote that I checked some sources. here is one: http://www.ctahr.hawaii.edu/hawaiirain/Library/papers/Abbots, Leder, Heyworth papers/Abbott.pdf

There is more to the contamination than the container; the level of contamination appears to depend upon where you measure.
 

donP

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Dec 14, 2008
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Dirty Rain

It is not so rare here that you get Sahara sand washed down in rain.
"Bodily waste" from humans and animals left to dry and then particles picked up by wind can also contaminate rain water.
Dried rain drops often leave a brownish reddish residue on our white roof and the car paint.

All right, such rain may not be as toxic as in industrial areas, but we prefer well water for all our needs.

donP
 

donP

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Dec 14, 2008
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Dirty Rain

It is not so rare here that you get Sahara sand washed down in rain.
"Bodily waste" from humans and animals left to dry and then particles picked up by wind can also pollute rain water.
Dried rain drops often leave a brownish reddish residue on our white roof and the car paint.

All right, such rain may not be as toxic as in industrial areas, but we prefer well water for all our needs (which - of course - can also be contaminated).

donP
 

cobraboy

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An RO system could make it potable. Spendy, US$6-10,000 depending. Sure beats crap water and 5gal. jugs.

Why not use a whole house sediment, carbon & .025 micron filter to produce potable water?

Inverters solve bad electricity. How about the water?
 

bdablack

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Jun 30, 2011
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In Bermuda all houses have to be built with a tank underneath the house. Rainwater is our main source of water as we have no rivers or natural lakes. We get some water from wells but that has to be processed before it is drinkable. Most people use well water for washing and flushing only!
We should sterilize our tank water more often but that is no the case and we have few illnesses. Additionally our tanks should be cleaned every 5 years, again most houses never do it and there are few health issues.
I've always wondered why DR builders rarely consider a tank.
 

cobraboy

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Jul 24, 2004
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In Bermuda all houses have to be built with a tank underneath the house. Rainwater is our main source of water as we have no rivers or natural lakes. We get some water from wells but that has to be processed before it is drinkable. Most people use well water for washing and flushing only!
We should sterilize our tank water more often but that is no the case and we have few illnesses. Additionally our tanks should be cleaned every 5 years, again most houses never do it and there are few health issues.
I've always wondered why DR builders rarely consider a tank.
That's interesting. A tank instead of a cistern.

A buried 2-3,000 gal. polypropylene tank properly plumbed and set up for easy removal of silt would make sense.
 

malko

Campesino !! :)
Jan 12, 2013
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That's interesting. A tank instead of a cistern.

A buried 2-3,000 gal. polypropylene tank properly plumbed and set up for easy removal of silt would make sense.

But for an equivalent volume, would it not be much, much more expensive if u went the tank route ??? On the same principle, one could collect rain water in a cistern.

And stratigical placed barrels that collect rain water, cuts out the water pump/ electicity ( or lack of it part ).

I combine all 3. Tinacoa ( when the mains has water, pressure fills it ), cistern to stock water when in need, coupled with the obligatory water pump( our village just went 8 or 9 days without water....... burst main pipe somewhere alomg the line ), and rain water for the garden, conuco and livestock ( pompous word for chicken, rabbits and formely pigs...... ).
 

jstarebel

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Oct 4, 2013
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An RO system could make it potable. Spendy, US$6-10,000 depending. Sure beats crap water and 5gal. jugs.

Why not use a whole house sediment, carbon & .025 micron filter to produce potable water?

Inverters solve bad electricity. How about the water?

One thing to remember is that all RO systems waste water. On the smaller household systems, the recovery rate of an RO is only 30- 35% meaning that they waste approximately 2 gallons to make one.

Keeping your cistern properly chlorinated to where there is 1-2 ppm free cl2 is important. Buy a cheap pool test kit to monitor the cl2 levels. Using the water for drinking is as simple as a 20" 20 micron filter followed by a 20" carbon block filter works well. For drinking, install a .4 micron ceramic filter on your drinking water line and you're good to go. It is highly suggested that you install pressure gauges before and after the filters to monitor pressure drop across the filters, so you know when they need to be changed. Normally, a family of four will change filters every 6 months, but make sure you change them at least every year whether they need it or not. Noticing chlorine passing the filters is another indication that they need to be changed. FYI, pleated filters that are "washable" are a waste of money. String filters pass as they plug up. Spun polypropylene depth filters make the best pre-filters. GAC (granular activated carbon) filters have no micron size and bleed carbon. Paper wrapped carbon filters have very little carbon in them and plug quickly. This is why I suggest carbon block filters.
 

Birdman

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Jan 29, 2013
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I think that you are talking about seawater. I used an RO system with river water and sea-water. It was very efficient. With river water I could turn the pressure right down for gallons of drinkable water to flow.
 

jstarebel

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Oct 4, 2013
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I think that you are talking about seawater. I used an RO system with river water and sea-water. It was very efficient. With river water I could turn the pressure right down for gallons of drinkable water to flow.

no. RO is cross flow filtration. The membrane requires a waste stream, and the flow of the waste stream determines the membranes "flux". The smaller the membrane, the less flux but the flows across the membrane stay constant. Not my rules. Simple physics. If you want to see for yourself, go to Reverse Osmosis & Nanofiltration . Small household systems work on very low recovery rates. Larger commercial or even large 800gpd or more whole house systems operate on 50% recovery. 75% can be achieved on certain waters or when anti scaling chemicals are injected into the feed water prior to the membranes. FYI, SWRO systems operate at a maximum of 45% recovery and usually more like 40.
 

Drperson

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Sep 19, 2008
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"For drinking, install a .4 micron ceramic filter on your drinking water line and you're good to go."
Would you have a link to what might be suitable to purchase for this? tks
 

william webster

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Jan 16, 2009
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When I build again, I plan a parallel system.

Main 5,000 gal cistern form a well.... run thru ultra violet to purify ($2,000 system from Sosua) for 'good ' water.

Supplemental rain water collection for bathroom use - showers & flushes. - separate water storage for the bathrooms

Rain water for gardens, etc.... sama as bathrooms

still in the planning stages