Irrigation design

The 5 steps to a perfect irrigation system:

The irrigation industry has accepted that certain factors must be considered for efficient irrigation. We spent years narrowing them down to the following five fast steps:

Step 1: Determine your soil type to know how to amend your soil. Amending poor soil allows water to migrate easily, adds nutrients, and is by far the single best thing you can do for your landscape.

Step 2: Collect information about the plants to be irrigated to determine how much water is needed to support them on a regular basis. For example, are they all 1-gallon Southern California native shrubs that will grow 4 feet tall when mature? Or a mix of types and sizes?

Step 3: Collect information about the microclimates on site to determine where you need to compensate for non-uniform watering requirements. For example, is a valve irrigating only in the sun, or does it wrap around a building into the shade?

Step 4: Calculate the number of gallons per day needed by the least-thirsty plant on each valve, to establish that valve’s base-line irrigation run time. For example, if the least-thirsty plant on a valve needs only .25 gallon per day, then two minutes per day (using one emitter) is that valve’s base-line.

Step 5: Calculate the number of gallons per day needed by the thirstiest plants on each valve, to establish how many more emitters to add for their higher water requirement. For example, if you add some plants to a valve that need twice as much water as the least-thirsty plants that only need one emitter, then put two emitters near those thirsty plants.

See ReWater’s Owner’s Operation Manual for additional design criteria including the Hydraulic Operating Parameters Chart on pages 15-16 created by the Center for Irrigation Technology (CIT). This CIT chart is required by California law for emitters using untreated greywater.