Installing a Backyard Rainwater Harvesting System

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Posted by @Bubbles on
If you've ever watched the rain shoot off your roof, across the yard and soak into your neighbors' garden, you may appreciate this article. What follows is a fairly inexpensive alternative to rain barrels on every down spout. It's easy to do, especially if you can talk someone else into doing it!

When our roof was replaced, off went the gutters.  Our house has three separate roof levels, and I was trying to decide how to re-do the gutters to catch some of the rainwater.  I had been whining for a rainwater tank, but my husband thought it was just another of my "crazy expensive ideas" (his words).

We were riding around one day and stopped to look at some of the rainwater tanks out on Highway 290.  There were at least three places that carried tanks and equipment  for setting them up . . . but not much instruction.  Once I had him looking, though, I wasn’t going to let up.

I called a fellow Master Gardener who had helped others determine where to place a tank, how big it needed to be, and the equipment and supplies needed to make it a successful installation.  As we walked the yard with the MG, I sensed my husband’s eyes were glassing over listening to our expert, as he calculated the expense of two 1500 gallon tanks, an $800 pump, and an aqueduct system to catch the optimal rain off the largest roof section.   I knew it wasn’t going to happen. 

Then one day we had a hard rain, a real “gully-washer.”  We stood in the window and watched all that water wash across the sidewalk, the beds, and then disappear into the neighbors’ yard.  I was on my soapbox again.

We drove up 290 a second time to look at smaller tanks since we were fairly certain our neighborhood association would frown on anything that would be seen from the street.  We had picked a spot for the tank to sit in the backyard without being visible to either neighbor.  After deciding we were going to get the one that fit in the back of the truck so we wouldn’t have to wait for delivery, we priced the 305 gallon tank at three spots.  Tractor Supply had the best price ($199.), the tank fit in the truck bed, and we were set to go.  About half way home, the wind picked up the tied down tank, and we had to make an emergency stop to re-tie.   After that it was smooth sailing and we arrived home in time to unload a fairly light tank.  A neighbor helped husband lift it over the fence into the backyard. 

We still needed a gutter to catch the rain, so we were off to the big box store the next morning for supplies; then it was time to get busy.  Husband put up the gutter on only one of the roof sections on the back of the house, a twenty-four foot length.  I believe at that time he still thought he was just humoring me.  He then covered the gutter with screening to keep out the oak tassels and debris.

The next day he set the tank, leveling the ground and placing the tank on a pad at the end of the patio and in front of my little greenhouse. (photo#1)  After another trip to get PVC pipe supplies, he hooked the gutter downspout to the "first wash'' pipe. When the rainwater flows into the downspout, there’s usually some initial debris that comes down also.  The first wash pipe keeps most of the debris from going into the tank. The "clean" water passes to the tank via a "T" pipe at the top of the first wash pipe and joins the inlet of the tank for tranferring the rain water.  (Photos #2 and #3)  At the base of the first wash pipe is a clean out cap for removing any debris that falls from the gutter and keeps it from going into the tank.  Be warned that you should not wear good shoes when you open this cap.  You will get wet! ( Photo #4) You can also see in the middle of photo #4 that we have a small electric pump on the wall of the greenhouse.  This is not the suggested $800 pump, but a $30 one from Harbor Frieght that has served us well.  There's a switch under the cover plate that turns the pump on to give me the ability to water the garden with some water pressure.

At the base of the tank is the outlet, where the water leaves the tank.  In our case, a PVC pipe with a cut off valve followed by a hose bib.  This gave us the option of using a hose connected to the pump to water the beds with some water pressure, or a separate faucet to just fill a pail or watering can. (Photo #5)

 2010-04-05/Bubbles/0a742e     2010-04-05/Bubbles/c161df 2010-04-05/Bubbles/46ae64 
#1 Setting the tank (it really is level, my photo is crooked!) #2 T pipe connects clean water to the tank #3 "Clean water flows from T pipe into top of tank


  2010-04-05/Bubbles/0d0d9d  2010-04-05/Bubbles/5a2057 2010-04-05/Bubbles/32b646
 #4 Bottom of first wash showing clean out cap  #5 Connections to hose bib and pump #6 Vines beginning to fill in

After completion, all we had to do then was wait for it to rain a little.  Husband was still a little dubious about the value of a rain tank.  That evening, one inch of rain fell into that 24 feet of gutter and our tank overflowed!  He became a believer!

We’ve hidden the tank from view of our patio with a decorative screen that is covered in vines in the spring and summer.  Our tank is right off one end of the patio and in front of our little greenhouse.  Unless we point it out to visitors, once the vines cover the tank in the early spring, they’d never know it was there. (Photo #6)

If the water develops an odor, you can add a little Clorox.  We've only done this once, when the oak pollen was bad the first spring.  Last summer, we noticed some mosquitoes in the tank.  We put a thin layer of oil on the surface of the tank water, and that took care of them.  After the hard freeze this past December, we had to replace the PVC pipes outward from the cut-off valve at the base of the tank connecting to the pump and the other faucet, as they froze and broke. I had failed to drain the pipes after the last watering.  That won't happen again!

We ended up investing about $400 in the project.  This included $200 for the tank, $30 for the pump, $100 for the PVC pipe and fittings, and about $70 for the new length of gutter and screening.  If you decide to install a tank, get the biggest one you can afford that is allowed in your neighborhood.  I speak from experience.  We are now considering another tank hidden on the other side of our house near the garage.  Once you’ve seen the top of your tank gushing overflow water during a spring rain, you'll realize how much rainwater is lost off the roof and down the run-off drains.  Besides, your plants will love you.

Comments and Discussion
Thread Title Last Reply Replies
Rain Tank hidden now by Bubbles Jun 30, 2010 7:33 PM 4
Great Article by Gymgirl Jun 18, 2010 11:37 AM 13
Untitled by Dinu Jun 8, 2010 7:07 PM 5
love mine by blkraven2 Apr 24, 2010 9:34 PM 0

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