Master Naturalists: Catchment systems good for water conservation

June 30, 2011 at 1:30 a.m.

Wildlife dripper

Wildlife dripper

By Paul and Mary Meredith

It has rained recently, but not much. The city is asking us to use water wisely. If the drought continues, it will be necessary to decide between water for plants or people, restricting watering plants and turf grass, or providing water to wildlife, etc., with city water.


First, conserve water following city guidelines. We see grass-watering at mid-day, wasting water to evaporation. After that, what else can you do? Modify your gutters and install a tank to collect rainwater? Not much use now, it'll catch dust until the drought abates. If you have a collector, use the water for landscape plants. Change your landscaping and turf to water-wise/native plants? Again, it's now too late and too hot to make changes, but a good idea - after the drought breaks.


Air conditioning may offer something you can do. If you have central air conditioning with a condenser unit outside and an evaporator unit in the attic, you're in luck. When your unit runs, there's free, clean, chlorine-free water you're throwing away every day during spring and summer. It's lost because standard installation of an attic unit takes water that condenses on the coils and chills household air. It then pipes that water to a vent pipe that goes to the city's sewer system. You paid to condense it and are throwing it away.


Scavenging air-conditioning-produced water is easy. First, check codes and deed restrictions before starting. Have you're A/C guy/plumber do the following; or, if you're handy, do it yourself. Reroute the air conditioner's primary drain from the attic down the side of your house and into a catchment (a rainwater barrel). Connect a hose to the barrel to water pot plants, favorite yard plants; and have some for birds and butterflies in a wildlife dripper.

Our system will capture about 3,150 gallons of water between April 1 and mid-October. Our 5-ton A/C system pipes to a 32-gallon barrel/trashcan. A hose connects to a wildlife dripper for birds and insects, plus to regular hose connections.

The amount scavenged varies with temperature (how often the unit runs) and humidity (high humidity, more water collected). The results are promising - 14 to 18 gallons of good water a day. If the wildlife dripper is off and Paul doesn't water, the barrel overflows after two days. It's not enough to water a yard, but is enough to water pot plants, keep tubs of Louisiana iris full, and have some for occasionally drip-watering yard plants. Is it worth it? If full water restrictions are imposed, it will be invaluable. We will still have water.

We have a second, 3-ton system. Will we scavenge it as well? Yes, and we'll then have 5,000 gallons total to water with each year.

Paul and Mary Meredith are master naturalists. Contact them at



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