Living In The Philippines Forum

Itís Your Money => Building in the Philippines => Topic started by: Gray Wolf on July 23, 2014, 01:15:26 AM

Title: Rainwater Catchment Guidelines
Post by: Gray Wolf on July 23, 2014, 01:15:26 AM
We just had power restored an hour ago. I have always believed in preparedness, and on the food and drinking water side we were fine, but the tank in the subdivision emptied in 24 hours after the power went out- so a few barrels of water for hygienic purposes will be in order.

The topic of water has come up several times recently.  Attached below is a very interesting study on Rainwater Catchment done by the University of Hawaii.  With all the rain the Philippines experiences some form of this should be standard equipment in every home

Title: Re: Rainwater Catchment Guidelines
Post by: JD on July 23, 2014, 02:03:43 AM
Roof catchment is definitely in my plan for stately JD Manor when we build it. I've been researching gray water reuse, too but that's gone into the "If We Can" file.

Thanks for the extra info, GW.

JD


[Edited to add this: Handy site for those interested in rainwater harvesting: http://rainwaterharvesting.tamu.edu/catchment-area/ (http://rainwaterharvesting.tamu.edu/catchment-area/) ]
Title: Re: Rainwater Catchment Guidelines
Post by: fred on July 23, 2014, 06:10:14 AM
This is an interesting topic for me and one I have had to think much about lately as the place we are building has absolutely no water mains from the municipal or barangay supply.. Although we will drill a deep well,the water from it is pretty much sea water.
We have a 250 (ish) Sqr mtr flat concrete roof.
Leading up to the second level we built a concrete staircase which got me thinking about turning the void beneath it into a concrete water tank/rain collector.
Now its done,I have calculated that it will carry 5 cubic meters of rain water!! The water from it then feeds a 20 cubic meter tank that we dug in the ground.. The rain water from there is pumped back up onto from whence it came..The roof!
Actually..The roof tank where it feeds the building via gravity flow.
Everything should work good..Providing it rains!
Title: Re: Rainwater Catchment Guidelines
Post by: coleman2347 on July 23, 2014, 07:59:31 AM
Fred,
Thats a great idea, especially if you have a concrete flat roof,  I would just make sure that the roof is stressed for it as its about 11k lbs if full.  (using Freds 5cubic mtr. capacity) .  How do you plan on filtering or treating it?  As it rains a lot here its one of the ideas I have been toying with when I finally build my house.  In this house we have a deep well that gives fairly good water so I really dont need it here but when I finally move its on the list to incorporate into the house plans.  During Yolanda as you can expect water was one of the critical needs and most here had access to none.  The doctor down the street and I both have deep wells so we ran hoses out to the street to the blue plastic barrels for anybodys use.  Lee
Title: Re: Rainwater Catchment Guidelines
Post by: fred on July 23, 2014, 08:31:09 AM
Quote
I would just make sure that the roof is stressed for it as its about 11k lbs if full

Hi Coleman..
The tank on the roof will be 2 plastic tanks that are 2 Cubic meters capacity each.. they will sit on the beams near a post so should be fine.. I realize its a lot of weight..Both tanks full of water is about 4 tonne!!

Quote
How do you plan on filtering or treating it?

The rain water will come through a 4" pipe which runs right down to floor level next to the tank exterior..This pipe has a clean out at floor level to get out any sand or stones that may be on the roof slab... there is a 4" tee at the top of the 4" pipe at top of  tank where the water goes in with a simple net filter..
As I said,this water feeds the underground tank.. From there the water is pumped out,through a canister filter to a pressure tank which fills the tanks on the roof.
Should work OK but I`ll let you know if it doesn't!
Title: Re: Rainwater Catchment Guidelines
Post by: paulgee on July 24, 2014, 03:20:59 AM
We decided to drill for water, others on our sub division had done that as the water flow to houses was pretty weak. Easily done, and we never connected our house to mains water, so our water costs are minimal, and we always have a pressure tank full of water. It is certainly purer than the mains water and we will get it tested for purity when we return there later this year.

I think anything which will stop you being reliant on the generally abysmal mains water available is worth considering.
Title: Re: Rainwater Catchment Guidelines
Post by: JD on July 24, 2014, 04:12:17 AM
The water in Davao is pretty good. I've had it straight from the tap on occasion with no ill effects although we always bought water during our stays.

We plan on having quite a garden so while treating the harvested water to make it potable is a possibility, we are thinking more along the lines of using it around the house.

If anyone is interested in the "first flush" idea of storing clearer water with less roof dirt/debris, this is a really good droawing of what that is: http://rainwaterharvesting.tamu.edu/files/2012/08/first-flush.jpg (http://rainwaterharvesting.tamu.edu/files/2012/08/first-flush.jpg).

The first bit of water with (hopefully) most of the dirt, bird poop and etc. in it fills the diverter chamber. Once it's full, the flow spills over to the piping leading to the storage tank. Pretty neat idea.


JD
Title: Re: Rainwater Catchment Guidelines
Post by: fred on July 24, 2014, 05:57:56 AM
The water in Davao is pretty good. I've had it straight from the tap on occasion with no ill effects although we always bought water during our stays.

We plan on having quite a garden so while treating the harvested water to make it potable is a possibility, we are thinking more along the lines of using it around the house.

If anyone is interested in the "first flush" idea of storing clearer water with less roof dirt/debris, this is a really good droawing of what that is: [url]http://rainwaterharvesting.tamu.edu/files/2012/08/first-flush.jpg[/url] ([url]http://rainwaterharvesting.tamu.edu/files/2012/08/first-flush.jpg[/url]).

The first bit of water with (hopefully) most of the dirt, bird poop and etc. in it fills the diverter chamber. Once it's full, the flow spills over to the piping leading to the storage tank. Pretty neat idea.


JD


Thanks for that link.. Good illustration of what I was trying to describe in post 4!
Title: Re: Rainwater Catchment Guidelines
Post by: medic3500 on July 24, 2014, 02:12:39 PM
I've been drinking the water from the tap here in Quezon City for two years and have had no problems. I know it is being treated somewhere along the way to the house as you can actually smell the chlorine especially after heavy rains like we have been having. 
Title: Re: Rainwater Catchment Guidelines
Post by: JD on August 05, 2014, 12:37:51 PM
Just stumbled on this tonight doing more research on RCS.

Houses, buildings soon to have rainwater catchers (http://www.sunstar.com.ph/davao/local-news/2014/07/03/houses-buildings-soon-have-rainwater-catchers-351612).

My wife's been rolling her eyes over my enthusiasm for catching that sweet, tropical rain for our planned garden but it looks like our future Mayor has signed off on it.


JD
Title: Re: Rainwater Catchment Guidelines
Post by: coleman2347 on August 06, 2014, 01:32:34 PM
Just stumbled on this tonight doing more research on RCS.

Houses, buildings soon to have rainwater catchers ([url]http://www.sunstar.com.ph/davao/local-news/2014/07/03/houses-buildings-soon-have-rainwater-catchers-351612[/url]).

My wife's been rolling her eyes over my enthusiasm for catching that sweet, tropical rain for our planned garden but it looks like our future Mayor has signed off on it.


JD

I had to convince my wife that rainwater is great, and would save us money in the long run..maybe its just here in Leyte but it does not seem to be a very popular way to conserve water...which has always mystified me as it rains hard and often here...
Title: Re: Rainwater Catchment Guidelines
Post by: JD on August 06, 2014, 03:09:30 PM
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
Title: Re: Rainwater Catchment Guidelines
Post by: paulgee on August 06, 2014, 03:47:02 PM
Quote
I would just make sure that the roof is stressed for it as its about 11k lbs if full

Hi Coleman..
The tank on the roof will be 2 plastic tanks that are 2 Cubic meters capacity each.. they will sit on the beams near a post so should be fine.. I realize its a lot of weight..Both tanks full of water is about 4 tonne!!

Reading the above made me think - I would bear in mind the usual build quality of houses in the Philippines when assessing it's load bearing abilities.
Title: Re: Rainwater Catchment Guidelines
Post by: FMSINC on August 06, 2014, 03:50:55 PM
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
Title: Re: Rainwater Catchment Guidelines
Post by: coleman2347 on August 07, 2014, 08:06:40 AM
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

No not here, here I just use deep well and city water...in the new place we are planing to put up in the province I will have all three, the roof of the House/store will be designed to funnel water into a below ground catchment system.  I can then use that to water garden etc...
Title: Re: Rainwater Catchment Guidelines
Post by: fred on August 07, 2014, 01:46:34 PM
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.

(http://img.photobucket.com/albums/v724/fred42/watertank_zps679c016b.jpg) (http://smg.photobucket.com/user/fred42/media/watertank_zps679c016b.jpg.html)

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.
Title: Re: Rainwater Catchment Guidelines
Post by: fred on August 07, 2014, 01:49:52 PM
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)
Title: Re: Rainwater Catchment Guidelines
Post by: coleman2347 on August 07, 2014, 05:42:16 PM
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
Title: Re: Rainwater Catchment Guidelines
Post by: JD on August 08, 2014, 12:11:53 AM
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
Title: Re: Rainwater Catchment Guidelines
Post by: JD on August 08, 2014, 12:18:36 AM
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
Title: Re: Rainwater Catchment Guidelines
Post by: hitekcountry on August 08, 2014, 12:53:57 AM
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 whatís available.
KERDI Membrane Wall Installation - Part 1 (http://www.youtube.com/watch?v=NkaJ0dRhY0g#)

other ideas
Waterproofing under tiles bathrooms terraces swimming pool shower floor (http://www.youtube.com/watch?v=KkXcxEQGgVQ#ws)

Sealing Pond with Thoroseal and Acryl-60 (http://www.youtube.com/watch?v=ny-zCi2gT64#ws)
waterproofing with liquid rubber
Contemporary Pond Made Out Of Wood Using Liquid Rubber Waterproof Sealant (http://www.youtube.com/watch?v=-CrowsyGzyo#ws)

Another idea would be to use an epoxy paint.
Title: Re: Rainwater Catchment Guidelines
Post by: coleman2347 on August 08, 2014, 01:26:47 AM
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
Title: Re: Rainwater Catchment Guidelines
Post by: fred on August 08, 2014, 08:29:28 AM
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 whatís 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.
Title: Re: Rainwater Catchment Guidelines
Post by: fred on August 08, 2014, 08:36:20 AM
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.
Title: Re: Rainwater Catchment Guidelines
Post by: JD on August 08, 2014, 09:38:45 AM
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