Thread: Rain water Harvesting

Hook tanks in series, add isolation valves and pressure activated floats to stop inflow or open flow. Use buried tank for primary source of water with above ground sump pump/lift pump. Put inline filters and isolation valve again. Pipe up to your system. You may wish to utilize existing well water so set up a separate isolation tank and settling pond. You may wish to use this as soiled water source only for toilets and other shitty water use. If you have a viable outside source for potable water use it!

If well unused some time have a sample analysed.
Are you aware of any agricultural or industrial contaminants in your aquifer?
Obviously worth asking around from neighboring well owners.

The fact it was potable in granny's da doesn't of course mean its safe now

For the well, try a couple of kgs of sansom.Available at many markets and used to clean/sanitise dirty water. some Thais still use this as a deodorant.It is actually Alum crystals in a rock like form.

Enough water for 6 people for 6 months is a fair sized storage tank. Not sure how much you use, but I guess (could be wildly wrong though) something like 100 liters day/person. That's 100 cubic meters you need to store.

Originally Posted by david44

If well unused some time have a sample analysed.
Are you aware of any agricultural or industrial contaminants in your aquifer?
Obviously worth asking around from neighboring well owners.

The fact it was potable in granny's da doesn't of course mean its safe now

Yes, a matter of course that meeds to be followed up in our modern times.
The romantic ideals of simple self-sufficiency and taking for granted that natural water supply will remain pure is a passing fancy.

Even the simple act of caste-stored water [aside from the complicated rain storage wells] needs to have a caveat attached today.

Originally Posted by Dan

Enough water for 6 people for 6 months is a fair sized storage tank.

I don't think he mentioned being totally reliant on the tank, merely wanting to harvest the rain. Although if he only used the water from the tank for specific purposes, it may last

Originally Posted by OhOh

Your "rain harvesting" system needs to be checked to ensure no hazards are introduced - polluted roofing material, polluted piping, polluted storage tanks

if it is all new built there shouldn't be a problem

when the first rains come, those should not be collected, just let them wash the cachment area clean of dirt

and water stored in a dark underground tank usually stays sweet

I did exactly this over 2 years ago and the house virtually runs on rain water but we are getting low at the moment we have hardly had any rain.

What I did was install two 7.5 cm tanks I have the space so they are above ground round the back of the house so we collect rain water from about half the house, if it had been a new build I would have built a huge underground tank.

The half of the house roof has partly a flat roof as well a pitched roof, the flat part I put a cement scread directing the water towards the tanks, the pitched roof which overhangs the back of the house where the tanks are I put guttering up and it goes straight into the tanks, once we get some rain it dont take long to fill up.

Then obviously we have a pump and i have a filter which I clean regular.

Also I put an overflow pipe on the tanks and that water is directed into the well.

I haven't bought any water for over 1 year I think I will have to soon if we dont get any rain.

Originally Posted by FarangRed

What I did was install two 7.5 cm tanks I have the space so they are above ground

what size again??

If they are above ground, then the water may get affected by heat etc...you don't have any problem?

My well (MIL's well) that was dug many moons ago is 30 plus meters to the water so I gave up that idea years ago. Our water table is that low too here in our area. Near Korat. I have fish ponds that I use to water the garden. I top them up from the Moo Baan at present. In the future I plan to save rainwater for this topping up. At present all of the water from my house roof drains into the "to be pond hole". In the future I will add a cistern between the house and the pond. For internal use, drinking, cooking, etc I use bottled water. Too much dirt in the air to use rainwater except as gray water.

Originally Posted by Ceburat1

Too much dirt in the air to use rainwater except as gray water.

certainly for the first rains, but after that usually the air is a lot cleaner (unless you live in a city)

Originally Posted by FarangRed

I did exactly this over 2 years ago and the house virtually runs on rain water but we are getting low at the moment we have hardly had any rain.

What I did was install two 7.5 cm tanks I have the space so they are above ground round the back of the house so we collect rain water from about half the house, if it had been a new build I would have built a huge underground tank.

The half of the house roof has partly a flat roof as well a pitched roof, the flat part I put a cement scread directing the water towards the tanks, the pitched roof which overhangs the back of the house where the tanks are I put guttering up and it goes straight into the tanks, once we get some rain it dont take long to fill up.

Then obviously we have a pump and i have a filter which I clean regular.

Also I put an overflow pipe on the tanks and that water is directed into the well.

I haven't bought any water for over 1 year I think I will have to soon if we dont get any rain.

Good for you, Red!

Originally Posted by DrAndy

Originally Posted by FarangRed

What I did was install two 7.5 cm tanks I have the space so they are above ground

what size again??

If they are above ground, then the water may get affected by heat etc...you don't have any problem?

Never had a problem and most of the day they are in the shade

First of all, i have read a lot of information about rain harvesting, there is no romantic fantasy, just a situation that calls for alternative methods. There is no issue with the water it just has a slight smell from the well, and id prefer to use water from the rain source to mix with it or use primarily.
There are many accounts of thai people using rain water and storing succesfully, and having a lower risk of disease and infection from contamination then other sources. Water needs to be controlled to stop legionaires but it only applies above ( ithink) 20Deg with growth prominent at about 34 deg.
There are however no serious and dangerous risks, and the implementation can be calculated simply to need. The fact that this is used widely as and where it is needed from poor 3rd world to 1st world means it is a viable source and contribution.
I really want to have people who have it to give me there understanding of implemntation and setup, not to rant of the ridicule of ignorance brigade.
First flush happens to relieve the build up dirt and comtamination from reaching your tank, but i want to know what people use for an automated system?
Tanks, concrete, ceramic, fibreglass?
Information woukd be great rather then opinion, and the nay sayers.

I have concrete tiles and 210 m2 roof space, there are no tree's near the roof, is there anything i can put on the roof to keep it cleaner less reactive?

Any information and real world help would be most appreciated!

As I said above, I have a large cement cistern in Portugal

after the first rains wash away the dust etc, I just channel the water into the tank until it is full; the tank then has a run-off to the garden

no automation, no problems

the water stays sweet, tastes great and is healthy

The tank is mostly in the ground, the water is always cool

The key thing here is to ensure all organic matter (leaves etc) are removed from any well or storage tank. Organics will taint the water and quite possibly produce an odour and yellowish water (like a weak cup of tea)
Any good rainwater system should comprise of a first flush device followed by dual filtration (20 @ 5 micron). If the end user is not used to captured rain water then I would advise some form of disenfection such as uv. The metabolisim of people used to city water is totally different to those in rural areas and it is common that they suffer from tummy bugs when consuming water from wells or tanks. e.coli is the main concern and without proper filtration or disinfection one is always at risk of falling sick. Of sourse it all comes down to the individual budgets and to do it correctly and safely is not always cheap.

I have never had any problems from my water from the cistern, always sweet

no hi-tech, no disinfecting, just rain water stored in the tank

Originally Posted by DrAndy

I have never had any problems from my water from the cistern, always sweet

no hi-tech, no disinfecting, just rain water stored in the tank

As they say in Thailand..."Up tp you"

Originally Posted by sailingman

Originally Posted by DrAndy

I have never had any problems from my water from the cistern, always sweet

no hi-tech, no disinfecting, just rain water stored in the tank

As they say in Thailand..."Up tp you"

they say the same in Portugal too

One stage of a small water tank we have here. I can't find the pics of the base of this, but you will get the idea when I post pics of the larger one.



Just checking photo sizes.

looks a good size - what will that hold when full? 20,000l?