Sun,
Mar 6
7:30 am |
Building
a Rainwater Collection System- About
two years after the house was completed, I decided to
put in rainwater collection for the few days in the
desert that we actually have rain. As with everything,
I wanted to keep it inexpensive and do the labor myself.
I went to the closest home improvement store and bought
brown guttering to match the fascia and looked up instructions
on how to gutter a house in one of the how-to books
I had bought during construction. That was pretty easy
- I have a fairly long house, so I decided to put a
rainwater tank on either end of the house and slope
the gutters from the middle of the house out to each
end. I think calculating the slope, so it ended up right
was the trickiest.
I
learned from another green-minded friend, a trick about
how to keep some of the dirty water out of the tanks.
Instead of having the gutter downspout go directly into
the tanks, the downspout branches and one part goes
straight down for about two feet, then ends. The end
has a rubber cap on it with a small hole. So, the first
dirty water off the roof goes straight down into this
tube. When the tube is full, the water then begins to
travel horizontally into the rainwater tank. If your
tank is below ground, then you can just make a short
horizontal run of the downspout before it dips down
into your tank.
Here is a photo from one side of my house with the downspout
and the horizontal tube running into the tank that is
behind the orange door.
For
tanks, I phoned a man that I heard about who sold rainwater
tanks made from big cistern pipes. You just had to cement
the pipe into the ground and he had a gauge out the
outside to show the water level plus a hose connector.
This was probably about 2005, before green was very
popular. Anway, I left him a message and got a pretty
funny, drunken voice mal back that he was no longer
in the rainwater tank business and he'd rather get divorced
again than start selling rainwater tanks. He did, however,
point me to a company that sold large plastic tanks,
so I went there. If you are considering this before
you built your house, or with time to bring a large
underground tank to your house, then by all means do
this. I hear some of the least expensive rainwater collection
tanks are (new) septic tanks underground. I was too
late to do that, so I purchase two 500 gallon upright
tanks. I had this feeling that if the tanks were upright,
I'd have enough gravity pressure to push the water into
my garden drip system. I rented a pickup truck for a
day and hauled both tanks up to the house. They were
light and opaque, so I could see the water level in
them. Here
is the one behind the door, that is half full of water.
The other is in the lattice area on the west side of
the house.
I
only wanted to use rainwater on the garden. I grow vegetables
and I am establishing trees around the property. I also
have some low-water use plants, such as agave. They
just need a little more than the desert offers. I did
the math and realized that the tank would have to sit
on a 50' hill in order to push the water up to 25 psi,
which is what my drip system required. So, I went in
search of a pump to increase the water pressure. After
phoning all over and searching the web, I came up with
an RV water pump that would turn on only when the drip
system ran and would be okay if it ran dry. Here
is a photo of the pump plumbed into pvc that runs from
the base of the rainwater tank. I have manual valves
that turn on the county water or the rainwater tank
when it is full. These pumps cost about $150 and I got
them at an RV supply store. They are made for solar
electric, also.
The
pumps have run for about five years now and been wonderful!
One of them started to leak once and JJ took it apart,
to find its gears full of gravel, so I put window screen
over the top of the tanks to do a finer filter. I think
the tanks cost about $300 each and with two pumps plus
gutters, I spent about $1000 on this whole system. Hope
this helps you and let me know if you have questions.
Keep
it Simple - and be kind!
Carolyn
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