*Inexpensive Roof Washer for Rain Water Collection*
By: Tengu
25 April 2012
Last year I started collecting rain water for my garden directly from one of my downspouts and, by the end of the season, the amount of dirt and gunk that collected in my rain barrels was amazing and disgusting. Over the winter, I looked at commercially available downspout filters and first flush diverters, but they were more costly than I expected ($140 - $320) and I was concerned that the less expensive ones did not look to be well built.
So, off I went to the hardware store to see what I could find that might be used to build one of my own design. What follows are my efforts to design an inexpensive, yet durable, downspout filter and first flush diverter. Below is the finished product leading into four cascading 50 gallon barrels...
The next photo shows the pieces that I ended up using for the downspout filter assembly. They are common items sold at any hardware store for under $10...
The endcaps are attached and sealed using gutter caulk, and gutter sheet metal screws, to the ends of the downspout adapter. Next, the downspout straps are easily bent to form the supports for the gutter screening material, which I set at a 45 degree angle and then screwed into place. This forms the first stage rainwater cleaning and collection process...
The end of the downspout that leads the rain water into my filter design is also cut at a 45 degree angle to allow the rainwater to flow into the filter unit. Any sediment from the roof that comes down the downspout rolls off the screen material...
The down spout filter unit then sits on top of an 8 foot long, 4 inch diameter PVC pipe (this and the misc. PVC part were under $40). About 6 inches from the top, I cut a 2 1/4 inch hole and connected a 2 inch PVC elbow using a very short piece of 2 inch PVC pipe, attached with a strong adhesive. I then attached a downspout elbow and a short downspout section to run the water into the first of four barrels.
At the lower end of the 8 foot PVC pipe I connected a 90 degree elbow, a short length of pipe, and threaded clean-out endcap. I then drilled a 1.5 inch hole in the middle of the endcap, glued a short 1.5 inch PVC pipe, then attached a 1/4 turn valve.
Now, when it rains, the first 5 gallons of water carrying (hopefully) most of the dirt off that section of our roof flows down the downspout and hits my downspout filter assembly. Debris that is larger than the screening material rolls off the screen and onto the ground, while the water drips through the screen and flows into and fills the 8 foot pipe.
When the water level reaches the 2 inch overflow pipe at the top of the 8 foot pipe, (mostly) clean water flows into my barrels. Later, after the rain stops, I go out and open the valve and let all the dirty water flow out, emptying the 8 foot PVC pipe of water. Now, I am ready for the next rain storm. This, hopefully, will keep my water barrels cleaner...
And a happy, well watered garden...
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