 Rainwater on Tap
By Ted Sterling
When Sara and I planned our house, we decided
early on that we wanted to be self-sufficient in our water
use. It rains plenty through most of the year to catch and
store water in large enough quantities to meet our needs
for drinking, as well as for the greenhouse and garden.
We calculated our anticipated need, added a margin to
account for drought and winters when the recharge rate
will be low, and then looked into cisterns.
Not relishing the formwork required for pouring a smaller
cistern, we looked into what the internet had to offer, and found food-grade
polyethylene tanks in the size we wanted, 1200 gallons. While we were not wild about
the use of plastic, we reasoned that it was a very durable good when used in a sunken
application away from any exposure to light that might degrade it, and one we could
expect to last the lifetime of our house. It was even weldable, with a small soldering
tool and a coil of thin polyethylene cable.
I discovered this when the cistern we subsequently ordered was already in the
ground and being filled with grid water for the first time in preparation for
backfilling. The morning after I'd filled it, I found the tank emptier and the hole
around it filled with water. It had come with a gash in one corner that went clear
through the cistern wall, and which I hadn't caught when we'd received it. The repair
has held up without any issue so far, and it is in a stable setting where I don't expect
any further problem with it.
We sank our cistern in the earth beneath our foundation where the insulation of
the foundation and ambient ground temperature would prevent any freezing. A
major carrying wall in our house crosses directly over the center of it, keeping it
pinned and obviating the need for any anchors to prevent it from erupting out of the
ground when the water table is higher than the water level in the cistern.
The one major mistake we made was to have the foundation dug before the tank
and backfilling materials were on hand and completely ready to go. There was a major
rain storm after the 7' deep hole and surrounding foundation trench were dug, but
before the cistern could be put in and backfilled. The thin wall between the trench and
the hole on one side collapsed, causing an erosive incursion of scouring rain. The hole
was filled with rain and the thick mud of the collapsed wall, which meant we had to
first pump out the hole with a submersible pump, and then dig out the most trenchant
mud you've ever met from deep in a hole.
The division of soil was essential to the functioning of our foundation's drainage
system, so we also had to rebuild it, sinking some hefty stakes in the gap to attach
siding boards to, and filling the cavity with tamped earth to recreate the barrier. It
made the resulting installation of the cistern much longer and more laborious than it
ought to have been, stalling construction on the house overall.
Most of the rest of the project went according to plan: we backfilled the tank,
attaching the input and outflow piping, as well as an overflow that drained into the
foundation trench's perforated drainage tubing. The input line went through the
foundation and emerged at ground level outside, where we planned to gather the
streams from our roof and greenhouse's combined catchment.
 Black ABS pipe is used for the exposed downspout portions of the system outside,
because it is drinking water-safe and UV-resistant. We installed valves allowing us to direct water either to the cistern, or, when
that is full, to our exterior rain barrels for
outdoor and greenhouse use. The rain
barrels are also the recipient of the contents
of the roof washer, which catches the first
few gallons of water that fall off the roof in a
storm and is emptied before the next rain
event via a gate valve at the base.
We chose to avoid the need for a
pressure tank and switch by installing a 55
gallon drum upstairs in our loft into which
we pump water from the cistern, then
allowing gravity's pressure to run our water
system downstairs. That end of the system
includes two faucets- one above the water
filter shelf inside, and one in the greenhouse
for the sink and coiled watering hose. Our
original plan employed a rotary hand-crank
pump for filling the upstairs tank. We
planned to convert the pump to run on
bicycle power. Once the greenhouse's raised
beds were installed, however, we realized there was insufficient room for the
stationary bicycle, so recently we replaced the hand pump with a 24v DC pump
operated by a float valve in the barrel upstairs, which automatically refills the barrel
when it starts to get low.
We use a British Berkey passive filter with four ceramic elements for our drinking
water. The filtration chamber above is filled via the faucet emerging from the wall,
and drips into the reservoir with spigot below. It never ceases to be a joy to drink our
water, knowing that after a bit of logical design, minor plumbing and electrical
wiring, we are supplied with high-quality, relatively pure rainwater for all our needs.
No need to worry about agrochemical residues and chlorinating agents typically
present in grid water in agricultural regions like ours, since the rain here generally
arises from the Interior West, with its minimal industrial pollution point sources, and
is then filtered to <.1 microns for drinking. This system probably cost about $2,000,
including the tank ($1200 including shipping- $1/gallon is a good average price to
shoot for in a cistern, according to Skyhouse's research), pump ($100-200), filter ($200)
and all guttering, piping and fittings. This is but one of the catchment systems
employed in the village. Others have been chronicled before in these pages, and can
be found in the March Hare archives on our website.
If this all sounds like more than you're up for, consider at least installing a water
barrel for watering your garden or lawn-downspouts can be easily diverted, and one
small porch roof or other roof pitch will probably provide you with a consistent
supply of stored water in most parts of this country.
Many companies sell rainwater collection systems for upwards of $100 these days,
but we get many of our barrels for free from a soda bottling plant. They're used to
transport the soda concentrate and then discarded. They come with convenient pipe-
threaded bung hole apertures that can be employed for leak-proof service. With $10
of plumbing fittings and a few basic tools, you could create a simple system yourself
the same way.
Enjoy! And please share with us any innovations you've worked out on your
own system.
Project Season •
Speaking "Rabbit" •
Peggin' and Lashin' •
Rainwater on Tap •
Top Down Fire •
Missouri Heights
Back to Newsletter Archives
| 
Intentional Community Bookstore