While waiting for my new
house to be built, I have been fixing up the old house--keeping to my
sustainability principles as much as possible.
Like many Californians I’m very conscious of saving water. One of the first things I did was to purchase
and install 4 rain barrels for rainwater catchment. BTW, if anyone is interested, the Bay Area
Water Supply and Conservation Agency (BAWSCA) (quite a mouthful) offers rebates
of $50 each for the installation of up to 2 rain barrels. As you can see from the fact that a rebate is
offered by BAWSCA, water catchment is encouraged. This wasn’t always the case. It used to be illegal and still is in some
states, like Nevada. Crazy!!
While rain barrels are
nice, I wanted to do more. An interesting
statistic is that the amount of water that can be collected from 1” of rain on
a 1000 sq ft of roof area is 600 gallons.
So you can see, a 50 gallon rain barrel is barely "a drop in the bucket." In fact, here in Half Moon Bay, the summer fog
drip can fill it up. Rather than add
more rain barrels, I decided to look into a larger tank. I met someone while I was on a garden tour who sold and installed tanks. Unfortunately, he was not interested in coming to Half Moon
Bay, so I started doing my own research
and decided it was a reasonable DIY project.
Little did I know I would have so many problems—mostly due to poor
advice and lack of information--the tank salesman was reluctant to give advice
because of liability issues and I had trouble finding the answers I needed
online. I had to learn a lot the hard
way, by trial and error.
First I needed a tank. They come in all shapes and sizes. The bigger the tank, the less the cost per
gallon, so it makes sense to get the biggest tank you can afford and have room
for. I also wanted one from California
so I could save on shipping costs. I
ended up ordering a 2500 gallon tank from Tank Depot and shipped from
Ukiah. To give you an idea of size, it
is approximately 8 ft high and 8 ft in diameter. Tanks with a capacity of 2500 gallons and
more have to be shipped on a special truck, but I was able to get a special
deal combining it with other deliveries and pick ups. I actually went ahead and ordered 3
additional tanks for the new house for no additional shipping charge.
One of the first problems I
ran into was the conflicting information people told me. Three different tank salesmen told me 3
different things about how to place the tank.
One told me it had to go on a 6” concrete slab; another told me to put
it on a 4-6” bed of sand; and the last
one told me it could be placed right on level ground. For the new house I will put it directly on the ground because it seems reasonable and is by far the easiest way to go. But for the old house, I just happened to
have an old concrete slab in the backyard, which I didn’t know what to do with,
so that is where I put the tank.
If you put a tank next to the
house and downspout, you can run the downspout straight into the tank. That is called a dry system since the pipe or
downspout is dry when it is not raining.
If the tank is away from the house, as mine is, you need to run the pipe
underground. The pipe goes down the side of the house, underground to the tank,
up the side of the tank and into a hole on top.
As long as the gutter is higher than the pipe at the top of the tank,
the water will flow into the tank. I
like to think of it as working like a syphon, using gravity and atmospheric
pressure. This is called a wet system
since the pipe stays filled with water.
Other things in the system
include a large access hole in the top of the tank and a screen to filter the
water and keep mosquitoes out. There is
an overflow pipe on the side near the top of the tank which can run to wherever
you like. And finally, it is recommended
to have filters at the gutter downspout and some sort of a first flush
mechanism. You can purchase the first
flush attachment or make one yourself.
It is basically a place to collect the dirt and debris that comes with
the initial runoff from the roof. It
consists of a pipe that comes straight down from the gutter with a cleanout at
the bottom. Somewhere on this pipe is a
T joint. Once the water fills the first
flush pipe, it spills over at the T joint into the pipe that goes to the
tank. The water in the first flush pipe
slowly leaks out so that it is empty for the next rain or it can be opened,
drained and cleaned out at any time.
Once I had my tank and had
done my research, it was time to put it all together. I hired a handyman who admitted he had never
done this before. While he and his 2
helpers dug the ditch for the pipe, I went to the store to buy the pipe. I couldn’t find anything online about what
size pipe to use, so we decided on 4” pipe.
I guess we were thinking that bigger is better. I went to the local business that sells
landscaping supplies and explained what I was planning to do and ended up
buying 4” solid drain pipe. The handyman
glued all the pipe together with an assortment of PVC cement he had on hand. Then the workers filled the ditch back
in. We got this all done just before a
big rain event was expected. It poured
hard that first night and I couldn’t wait to see what was in my tank. But, unfortunately, the next morning the tank
was still empty. Upon inspection, I found
one of the above ground pipe unions had come completely apart. I glued it back together and waited for more
rain, which came again that night. The
tank was still empty the next morning and I found another joint that had come
apart. I then tested and re-glued every
joint I could access and it still didn’t work.
Thinking that the problem was underground, I began digging up sections
of the pipe and re-gluing. When that
didn’t work, I dug up the entire pipe.
Not only was the tank not filling, the “wet” pipe was not holding
water. It was slowly leaking out. When I tested using a hose, I could get water
to go into the tank, but first it had to fill up the pipe, which should have
been holding water. I went back to the
store that sold me the pipe, explained the problem, and he said he had never
heard of such a thing and sold me “the best” PVC cement and I again re-glued
every single joint. When the problem
still existed, I knew it was time to go to plan B.
Drain pipe is not intended to
be pressurized, but I thought the pressure was so minimal that it would
work. (An engineer friend of mine calculated the
pressure to be 4 psi. ) But it just wasn’t
working, so I removed all the pipe and replace it with 3” Sch 40 PVC which is
made for pressures up to 250 psi. A tank salesman recommended Sch 80 but I thought that was way overkill. One of the main problems with using the drain
pipe, as I did, is that it is not PVC, so PVC cement does not work as intended. Perhaps if we had glued it with something
that actually worked, it wouldn’t have leaked.
By the time all this was
done, the rainy season was over. It
wasn’t until the rains came in October that the system was given a real life
test and the tank quickly filled up!!!!
One of the biggest mistakes I
made in this process was having the workers fill in the ditch before the system
was tested. Of course it was done for
expedience and convenience. The workers
were only here for the day. However, I
ended up having to dig the dirt back out myself and digging the dirt from
around the pipe was actually harder than digging the original ditch.
While my system works great
with the 3” pipe, I’m still not sure how to determine what the optimal size
pipe would be. The larger the diameter of the pipe, the more expensive it is
and the harder to work with, so putting in a larger pipe than needed is a waste
of money. While writing this blog, I did
find a chart from the Uniform Plumbing Code for sizing vertical
downspouts. The pipe size is based on
roof size and maximum rainfall per hour.
They don’t include any pipes under 3”.
For my roof size of 1600 sq ft a 3” pipe is sufficient to collect
rainfall of 4”/hr, which is more than sufficient for my location. Check out harvestingrainwater.com. Maybe I could have gotten by with 2” pipe, or
at least 2 ½”.
My 1600 sq ft roof has 5
downspouts. Two of these are hooked up
to my catchment system. The pipes come
together underground. I tried to block
the other downspouts to get as much water as possible to go into my large tank,
but haven’t had much luck. It seems like
it would be easy to do because downspouts get clogged when we don’t want them
to—a kid’s toy gets washed into the downspout, etc. Until I get that figured out, I am placing
buckets under the extra downspouts to collect at least some of the water.
So now that I have all this
rainwater, how am using it? The obvious
answer is for plants. And don’t forget
the houseplants, they love it. That is
all fine and good when it isn’t raining, but right now the ground is saturated and
the outdoor plants do not need water. So
how else can I use it? It hasn’t been
properly filtered for human consumption, but I’ve been using it for my
chickens. The other day I used it to
wash my windows and it worked quite well.
I filled a bucket and added some vinegar and sponged and squeegeed my
windows. But mainly I’ve been using it
to flush my toilets. I keep buckets full of water ready on the porch. Unfortunately, the new low flow toilets don't flush as well with a bucket as the old toilets did.
I am using gravity feed to
access the water in the tanks. The rain
barrels have a spigot near the bottom. I
use that to fill buckets or a watering can.
My large tank has a valve and hose bib at the bottom for the same
purpose. You can attach a hose to get
the water where you want it to go, but, remember, the pressure won’t be what
you are used to and a spray nozzle might not work very well. You could use a pump, but I haven’t found it
necessary for what I am doing and I like low tech systems. My biggest worry, though, is that I will
accidentally drain the tank. Let’s say I
attached a hose to my tank and let the water run into one of my planter
boxes. If I forget to turn the water
off, it is possible that all the water could run out of the tank. That is not a huge problem with a rain barrel
because it holds a lot less water and fills back up much more easily. I’ve been giving a lot of thought to this
problem, but since my tank is only now filled for the first time and I have not
needed to use it, my ideas have not been tested. For a mechanical solution, they make timers
that can be attached to the hose bib and set to shut off after a specified
length of time. But I’m not sure I’d
want to trust that. What if it didn’t
work? Another option would be to put
your smart phone to use. Every time you
turn the water on and leave it, set your timer to remind you to turn it
off. A really old “no tech” trick would
be to put something like a rubber band or a Scunchy on the valve on the
tank. As you turn on the valve, transfer
the Scrunchy to your wrist. The Scrunchy
will remind you that the water is on. I
plan to put a shut off on the end of the hose so I don’t have to go back and
forth from the tank to turn on and off the water, though my intention will be
to turn off the water at the tank, as well, when done. And I may find I do not need to leave the
water running unattended. To be on the
safe side I might plan to utilize more than one type of reminder or timer at a time.
It is looking like the
drought in California will be officially over this year. But that is no excuse for going back to
wasting water or not continuing to conserve.
I’ve lived my entire life in California and there have always been
droughts and always will be. Conserving
water should be a normal part of our lives, not just when there is a drought or
the water district enforces restrictions.
Unfortunately, people have short memories. It reminds me of what goes on around gas
prices. When gas prices go up, the sales
of fuel efficient cars goes up, but as soon as prices go down, everyone starts
buying big cars and trucks again. We
need to think about tomorrow today.
I wish I had bought a trailer
load of tanks. When people see the tanks
sitting on my vacant lot, they ask about the tanks--if I am selling them and
where they can get one. I wish I had tanks to sell to them and could get more people harvesting their rain water.
