Water Efficient Irrigation

Half of the average water bill in Southern California pays for landscape irrigation. Use these tips to save water and money.
Water on Schedule

Plants come in four categories – high, moderate, low and very low water use – and the recommended watering times are different for each category.

Two Scheduling Tools

Weather-based, or smart, irrigation controllers automatically adjust watering times each day based on weather data from sensors you install on your property or from the State of California’s CIMIS weather stations via the internet.

If you have an older irrigation controller, you need to enter the correct watering times yourself and you can get them with the city of San Diego’s Landscape Watering Calculator.

Use the Most Efficient Sprinkler

Our sprinklers put a lot of water on our landscapes, but only a percentage of it is absorbed into the soil and into the roots of our grass, plants and trees. The higher the percentage, the more efficient the sprinkler is.

Spray Nozzles

Spray nozzles are very common but have two issues: they apply water faster than most soils can absorb it, and wind can blow the small water drops off target — causing water to run on to sidewalks and into the street.

50-70%

EFFICIENCY

Rotors

Rotors shoot a single stream of water that moves slowly over a landscape, giving soil time to absorb the water. Rotors are commonly used on large landscapes.

80%

EFFICIENCY

Rotary Nozzles

Rotary nozzles apply water slowly and produce large, wind-resistant water drops. They can be up to 30 percent more efficient than spray nozzles and are the best choice for watering a lawn. Replacing spray nozzles with rotary nozzles is simple – watch our video.

80%

EFFICIENCY

Drip Irrigation

Drip irrigation applies water slower and deeper into the soil, and is the best way to water plants and trees.  Not irrigating the area between plants saves a lot of water and reduces weeds, and installation is easy – watch this video.

90%

EFFICIENCY
Prevent Water Runoff

If your sprinklers apply water faster than your soil can absorb it, water will run off of your landscape, on to the sidewalk and into the street. You can avoid runoff by using rotary nozzles and drip irrigation, or by reducing your watering times and watering more often.

Use Multiple Start Times

Some irrigation controllers offer multiple start times on the same day within one program, while other controllers require you to use multiple programs.

On Start Time 1 or Program A:
Schedule the same days and 3:00 minutes at 12:00am

On Start Time 2 or Program B:
Schedule the same days and 3:00 minutes at 2:30am

On Start Time 3 or Program C:
Schedule the same days and 4:00 minutes at 5:00am

Use the Cycle and Soak Option

Some irrigation controllers have a cycle and soak option, which will automatically divide a 10 minute watering cycle into smaller cycles.

 

Regulate Your Water Pressure

The optimal water pressure for drip irrigation and sprinklers ranges from 20-40 psi. But a home’s water pressure can be as high as 70 psi.

What Happens

Below is an excerpt from a spray nozzle performance chart. The nozzle’s optimal water pressure is 30 psi, and at 40 psi the nozzle’s flow rate increases by 0.4 gallons per minute. That’s wasted water. It doesn’t sound like much, but it adds up quickly.

4

GALLONS WASTED BY ONE SPRINKLER IN 10 MINUTES

240

GALLONS WASTED BY 60 SPRINKLERS IN 10 MINUTES

33,120

GALLONS WASTED BY 60 SPRINKLERS IN ONE YEAR

MEASURE YOUR WATER PRESSURE

Water pressure gauges are available at hardware and irrigation supply stores. Screw a water pressure gauge on to a hose bib outside your home and turn the water all the way on. If your pressure is higher than your sprinklers’ optimal pressure, you’ll save water by installing pressure regulation devices in your irrigation system.

INSTALL PRESSURE REGULATION

Manufacturers make pressure regulators and valves and sprinklers with built-in pressure regulators. Learn more by watching videos on manufacturer websites and ask one of the experts at an irrigation supply store what they recommend.