Rain Source Water - Free Water...It's On The House

For many years I had been thinking about installing a rainwater tank in our backyard. Most of my irrigation was drip irrigation and didn't waste that much water, so I thought I could catch enough to see me through the summer months by installing a tank that would hold about 1,000 gallons. Well, I thought and fretted about the space it would take to accommodate a tank that size. We had limited yard space after years of developing our landscape. There was one spot behind the garage that could accommodate a tank, but my wife wanted a greenhouse and there wasn't enough room for both. Back to the drawing board, I thought. But wait. why was I limiting my thinking to above ground? I had been studying stormwater management techniques for some years and the answer to my problem was right there all the time. Put it underground. The concept was liberating. Now I had a solution to the space problem. But, does the phrase "be careful what you wish for" ring a bell? I still had to get a tank large enough to hold 1,000 gallons of water into the space behind the garage. I would have to tear down a fence. Not a huge problem, but still an obstacle. Also underground tanks are different from above ground tanks in as much as they have to stand up to exterior pressure when they are empty or partially empty plus they are heavy and would be hard to lift into the excavation. So it reduced my selection of appropriate material even more. What started out as a great solution was now becoming more and more discouraging. Still I was undeterred. I wanted to catch rainwater more than ever and now even my wife was wondering how soon we could expect to see some progress. After all it was late September and the rainy season would be upon us soon.

Our garage roof is an excellent source of water. It is a typical 2 car garage, 27 feet by 20 feet. By a simple calculation (which is included with this report) we found we would generate 431 gallons of water for every inch of rain. So in our situation it would only take 3 inches of rain to fill our cistern.

I work for a company that sells pond building material. One of the products we use to capture additional water in features with gravel basins is an extruded plastic box much like a milk crate but stronger and it snaps together, they are very light and they come as a flat package.

I started putting together a few of them in the warehouse one day and found that I could build a basin that would hold 1,100 gallons by stacking 36 of these boxes side by side and on top of each other. What I discovered was I just solved two of my problems, one having to tear down the fence and move a tank into place (size) and the other lifting the tank into the excavation (weight).