Rainwater Catchment Guidelines

[fred]

You can build a large under ground storage tank out of cement blocks just plaster it on both sides and use rebar in the construction, just add some chlorine to the water to keep the algae down should not be that expensive with local labor and it will last a very long time.

Tom / Roxas City

We built one like that a couple of years ago.. It was OK until  the water went above half way up and the pressure pushed it through an inch of cement render and through the hollow blocks.
We have just built a steel reinforced 4" cement poured water tank.. The pour was -2-1 sieved sand/cement with 2 bags of sahara waterproofer and let it cure for 3 weeks..
It seems incredible but we filled it with 10 tons of water and it started seeping through outside after about 10 minutes.
The problem is that the tank is narrow,but long and high.. Its the height that is causing problems.. We are tiling the tank interior next week and grouting with a hydraulic water barrier paste..
We have a 20 tonne underground storage tank and although it doesnt seem to lose water,its hard to be completely sure.



Our local Barangay built a huge one on stilts made from CHB and render.. The water was in there for about 20 minutes..Leaked exactly like a sieve.. Abandoned now.. No budget to fix.

[fred]

I guess I'll have to wait to price storage tanks and the like until we're in Davao as there's little local info online. I did some some local Mindanao newspaper photos featuring huge steel tanks but I'm not sure I want one of those.

Do you have a system, Coleman?


JD

JD..
Here in Bohol a 1,500 liter nylon tank (Bestank) is 13k.. A 2,000 liter nylon tank is 23k. (as of yesterday)

[coleman2347]

IMHO nylon or stainless steel is the best way to go, in the place I lived before I had a plastic tank that was in a cement container about 4 ft to ground level.  Everytime it rained hard the cement tank that held the plastic one would fill up from ground water and float the plastic one, I had to install a submersible pump and turn it on to keep the water out....sealing concrete here seems to be one of the things you cant get stuff to do. But hey, this is Leyte, you probably could in Manila, Cebu or Davao ...I dont really know...Im planing on putting several stainless tanks in series in a concrete container when I do the property I just bought....more will be revealed in time I guess

[JD]

JD..
Here in Bohol a 1,500 liter nylon tank (Bestank) is 13k.. A 2,000 liter nylon tank is 23k. (as of yesterday)

Thanks much, Fred! Good luck with your concrete one. I'm really interested in these types of real-world projects. Keep us posted on yours.


JD

[JD]

IMHO nylon or stainless steel is the best way to go, in the place I lived before I had a plastic tank that was in a cement container about 4 ft to ground level.  Everytime it rained hard the cement tank that held the plastic one would fill up from ground water and float the plastic one, I had to install a submersible pump and turn it on to keep the water out....sealing concrete here seems to be one of the things you cant get stuff to do. But hey, this is Leyte, you probably could in Manila, Cebu or Davao ...I dont really know...Im planing on putting several stainless tanks in series in a concrete container when I do the property I just bought....more will be revealed in time I guess

Ah, a vault. I get it. I was sort of thinking to keep our future one above ground. Not sure why. Maybe because of all the diagrams I'm seeing, the tank is above ground. Maybe it seems less complicated. Is in-ground better?

JD

[hitekcountry]

We are tiling the tank interior next week and grouting with a hydraulic water barrier paste..

Fred
You might want to consider installing a waterproofing membrane prior to installing the tile. This video is just one example of what’s available.

KERDI Membrane Wall Installation - Part 1	Small | Large

other ideas

Waterproofing under tiles bathrooms terraces swimming pool shower floor

Sealing Pond with Thoroseal and Acryl-60

waterproofing with liquid rubber

Contemporary Pond Made Out Of Wood Using Liquid Rubber Waterproof Sealant

Another idea would be to use an epoxy paint.

[coleman2347]

JD, I like below ground just because its out of sight, and I also like the liquid rubber above as you can get that here....
On the other hand having tanks on the roof or elevated makes a lot of sense using gravity flow...matter of choice I guess

[fred]

We are tiling the tank interior next week and grouting with a hydraulic water barrier paste..

Fred
You might want to consider installing a waterproofing membrane prior to installing the tile. This video is just one example of what’s available.

Another idea would be to use an epoxy paint.

Thanks for the videos!

The trouble is that my options are limited here because of whats available locally..
My first idea was to buy plastic sheet as a membrane. (the stuff they cover book sleeves with) The thickest grade comes in 4 foot widths on a roll..Either that or floor lino..The problem is that the only thing I can find to stick it to the inner walls is rubber glue..In the Philippines its called Rugby..
Rugby is adequate I think but applying that stuff inside an enclosed space would be almost lethal because of the fumes. I`d end up with either an extremely high.. or dead mason!
There is an imported 2 part epoxy product here for this purpose but the costs are prohibitively high.. Same goes for epoxy primer and epoxy enamel..
Once Ive grouted the tiles as described, I might even coat the seams,edging etc with a thick application of Vulcaseal.
I feel confident it will work but if it dont then I will report the failure here and hang my head in shame!!
Thanks again.

[fred]

JD, I like below ground just because its out of sight, and I also like the liquid rubber above as you can get that here....
On the other hand having tanks on the roof or elevated makes a lot of sense using gravity flow...matter of choice I guess

Coleman..
In our house we put a 200 liter header tank above each bathroom..
So glad we did because when a brownout hits and the water stops,we at least have 400 liters of water thats available via gravity feed.
I dont think we could do without them to be honest.

[JD]

In our house we put a 200 liter header tank above each bathroom..
So glad we did because when a brownout hits and the water stops,we at least have 400 liters of water thats available via gravity feed.
I dont think we could do without them to be honest.

How do they fill, Fred? From the catchment system or from the municipal water system?


JD