Another tactic: small trenches around gardens and dips in the topography that cause rainwater to puddle around plants with roots that can tolerate it. This helps keep moisture from running off the lawn and into sewers, leaving it to soak into the ground.

“The key to conserving water on the outside in the landscaping is, No. 1, the way you create the lots so you retain the natural rainfall … as long as possible before it falls off,” agrees Arizona builder John Wesley Miller.

Go With the Flow

Following smart layout and careful plant selection, products designed to further conserve and better manage water on the property also come into play.

Creating a yard that requires little watering lets a homeowner or even a developmentwide landscaping service get by using captured rainwater to keep plants healthy instead of potable, irrigated water. Rainwater catchment systems harvest runoff from roofs and gutters into barrels that are connected to hoses and pumps, which stand in for an irrigation system that relies on city water. Rain barrels range from large vessels with attached garden hoses to underground cisterns that work in tandem with a sophisticated distribution system.

To earn points toward LEED certification, a cistern would have to catch at least half of a home’s roof runoff and include a pump, which can be put in the home’s basement.

Another technique is the distribution of greywater, or water collected from household drains (not the toilet) that can be reused for landscape irrigation (see “Grey’s Anatomy,” left)—although it’s one that builders and some jurisdictions are not warming to quickly. (Some cities and states will not grant permits for new construction or remodeling projects that include greywater reuse because of concerns that greywater contains bacteria and chemicals that people, and even pets, might come into contact with.)

For the parts of the landscape that do need regular watering, water-conscious builders rely on drip irrigators that slowly wet only the plant that needs attention rather than spraying water over a whole lawn, often including trees, porches, and driveways. Drip irrigators are rigged to timers to deliver a precise amount of water on a schedule that eliminates unnecessary watering.

The newest irrigation systems are so “smart,” they can sense whether it has rained and how much, and will skip a scheduled watering if it’s not needed. They are programmable to recognize the type of plant being irrigated and to deliver the specific amount of water that species needs.

Stopping Power

Just as important to a landscape design is controlling storm-water runoff from paved areas, which can take with it excess chemicals and sediment.