By Jim McCausland, Sunset senior garden writer

For decades the prevailing philosophy about rainwater was to catch it and route it into a storm drain. But eventually some parched soul (probably in New Mexico) questioned the point of sending your most treasured resource away as quickly as possible.

In most western states, you can legally capture the rainwater coming down your downspout and store it for use when you need it. The easiest capture is with a rain barrel. You have lots of options (see a few at the Gardener's Supply Company web site), including plastic and wooden versions. When wooden ones dry out (as old wine barrels do), the wood can shrink enough to open leaky seams in the sides, so if you use one of these, keep it damp so the wood stays swollen and the seams stay tight.

Most rain barrels hold between 50 and 100 gallons of water. They fill remarkably quickly, but you use up the contents fast. For that reason, their highest use is to capture rainwater for irrigating house plants. (If you want to use these for garden watering, buy a cistern that holds at least 1500 gallons; details to come in another blog.)

Rain barrel placement is critical. Put it high enough so that, if the tap is on the bottom, there's room to get a watering can under it. Also get a downspout diverter (Gardener's Supply has those too). When a storm blows in, let it rain for an hour before you divert what's coming down the downspout into your barrel. That give the rain time to wash away dust, pollen, and bird droppings before you start routing the water into the barrel.