Sarah Cooke is a local restoration ecologist and native plant botanist known locally in her neighborhood as the “chicken lady” because of the tractor on her front lawn that everyone comes to visit. She has maximized her tiny Seattle lot with gardens and chickens and bees (both honey and mason) and fruit (she just aded Himalayan banana, pomegranate, tea plant, and Gojii berries)
I came into the decision to buy a cistern one fine summer day a couple of years ago after opening my Seattle utilities bill and seeing how much watering the gardens was costing me. It was a small fortune and meant that all the veggies and flowers I was growing on my small property were costing me as much or more than buying them at the store, which was way too much, and so opposite of my intent of growing them in the first place! Plus I have the added issue that I let my chickens free roam the back yard and every few days I have to walk around and squirt the chick poo into the grass so we can walk around barefoot. It makes for a lovely lawn but a ridiculously high water bill.
So, right about that time I happened to click on some blog somewhere that talked about greywater and rainwater collection systems. Technically greywater systems are not allowed in Seattle. I tried hooking up my washing machine drain to go outside and water the rose garden but the lint kept clogging the hose so that was a bust. Oh sure, I had rain barrels on all my downspouts but frankly at about 50 gallons each, it was almost a joke how little time they lasted and once the rains stopped they remained empty for most of the summer. Seems like they are full when I didn’t need the water in the spring (when it was raining all the time) and dry when I did- It was all very unsatisfying!
In steps Nicola Davidson of Earth Systems NW….
I was short of cash but high on enthusiasm and Nicola came to give me an estimate for a real cistern rainfall system. She did the calculations and my roof generates 35,000 gallons of rainwater a year! Who knew? Calculate how much water YOUR roof generates at http://earthsystemsnw.com/calculator.html. Do you know how many chicken poos that will water into the grass alone!!! I was in. My first decision was above or below the ground, the next how much water I could store. I did not want to bury the tanks as my property was already set up with fences and gardens and the coop that is semi-permanent so it was above ground for me. Still, I had to deal with having a very small and already maximized Seattle Lot, so I walked around and found 2 spots in the back and one in the front where I could stash a largish tank.
Polyethylene! Upon researching the different materials that tanks are made from- it was clear that polyethylene is the way to go. It develops a biofilm on the inside that protects from any potential off-gassing and it is relatively UV safe and supposedly lasts for at least 20 years. Sediment sinks to the bottom and the outlet is at the bottom so it is always flushing itself. I went online to see what tanks looked like and what sizes were available. I found 2 tanks on sale that would fit the two spaces in the back yard with my raised bed vegie gardens (850 gallons and 550 gallons) so I was all set. I figured if they both only filled up once per season they would pay themselves off in 5 years (installation included). With filling up multiple times a season it will pay itself off much quicker. Frankly, after last summer and all the rain we had I am now at paying it off in 3.5 years.
So how did the costs break down? Well, Nicola charged me $1500 to 1) prepare both pads that the tanks sat on (a layer of sand, a layer of gravel, and pavers) replumb all my downspouts on the backyard side of the house, quite an extensive system that included remounting my gutters so they drained in the right direction and 3) plumbing in overflow spouts for when the tanks fill (and they do). Plus adding in the brass ball valve and outlet. All ready to screw on a hose. I already had screens on my gutters. That would have been necessary if I didn’t already have those.
You ask about water pressure. Well, when the tanks are full it is not an issue. With that much head the water gushes out and I found a awesome attachment at the Puyallup fair that gives me pretty high velocity. Enough to squirt those chicken poos right into the grass so they are invisible and to wash the deck in the back. It is not enough to run a sprinkler however, which would be nice. The smaller tank I use a water wand that works great for the veggies. When both tanks get low (less than ¼ full) the pressure is lousy. This is not a problem if you are into the whole Zen of watering and have lots of time, but that is not me. I want to water quickly and be done with it. This is where the adding a small pump comes in. Nicola sells different systems but again, with the economy, I have been pretty broke so I did research on my own. I found out there are two options- submersible pumps that fit inside the tank or external pumps that are less expensive and not as powerful. But this spring, after 3 years of the slow watering regime, I had had it. So, a couple of weeks ago I Googled “Cistern Pumps” and found an external pump that came highly recommended that was on sale for $50. It arrived and works great. It took 5 minutes to hook up. I have an outlet outside the back door right next to my 850 gallon cistern and I just have to mount pump onto the deck, but, Now it takes no longer to water than with the regular city water system and there is enough pressure to run my sprinkler system that I have set up in my raised beds. YAHOO. I do need to install an on-off switch because I have to plug the pump in each time I use it, but that is another project.
My next project is getting a cistern in the front yard where I have my flower beds. Nicola has a design for a trellis and bladder system (called a water fence) that I can hide behind some siding so it looks like a continuation of my house and doesn’t fill my frontage with a huge plastic tanks. For the pad I have it will give me 1200 gallons of water storage. That will be a bit more spendy so that is a project for down the line, but one I am sure I will do it. In the meantime, I did install a greywater system from my upstairs tub and sink and I still have 2 downspouts from the front half of the roof that fill up each time it rains, so I generate 100 gallons every rainfall and the greywater tank keeps filling so long as my kid and I shower.
Time to sign off. It is raining again and I smile knowing not only is the garden getting watered but the cisterns are filling at the same time!
Yours in Free-water
Sarah Spear Cooke
US Plastic Corp
Oasis Design Company
National Tank Outlet
Northern Tool + Equiptment
The Tank Depot
Nikola Davidson at Earth Systems NW
US Plastic Corp
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