Rain barrels for home water conservation
An overflow outlet needs to be put near the top of the barrel, or about 2/3 the way up if you are ganging two barrels together. A common problem is for people to make their overflow hose too short. Make sure it doesn't drain too close to the house or it could damage the foundation.
Cover the top of the barrel with screening that is held on with a bungee cord. This keeps debris out of the barrel. If you can't connect the down spout directly to the rain barrel, you might use a rain chain to funnel the water into the barrel. You can pay up to $80 for a fancy rain chain or you can make you own out of a clothes hanger with chain hanging from the center of it.
Disconnect the rain barrel before winter and store it upside down until spring when the danger of freezing is past.
In addition to the conventional reduction of water usage for landscape use, rain barrels can prevent erosion due to runoff and reduce water that enters the storm water drains. Also, rainwater gathered in rain barrels does not contain chlorine or other chemicals that are added to city water.
An easy way to figure the rain you can harvest from your roof is for every square foot of roof that drains into the down spout, you will collect one-half gallon for each inch of rain that falls.