Landscape Irrigation Rates

Water budget formula

ET x Kc x 1.25 x LA = landscape potable water budget in acre-inches. ET x Kc x 1.33 x LA = landscape recycled water budget in acre-inches.

To convert CCF, multiply by 36.3. CCF stands for “hundred cubic feet.” One CCF equals approximately 748 gallons.

The four factors used to determine a budget for a particular landscape area:

ET (evapotranspiration) – from IRWD weather stations located in coastal, central, or foothill zones.
Kc (crop coefficient) – is the relative amount of water drought-tolerant plants need at various times of the year. A crop coefficient of 0.6 for drought-tolerant landscapes is applied for potable irrigation, and a crop coefficient averaging 0.65 for warm-season turf is applied to recycled water irrigation.
No irrigation system is 100% efficient. IRWD assumes an irrigation efficiency level based on spray head and drip irrigation systems and includes this extra water in the outdoor budget. An irrigation efficiency of 80% is applied to potable water and 75% to recycled water. In the formula, this is calculated as = 1/0.80 = 1.25 applied to potable customers and 1/0.75 = 1.33 applied to recycled water.
LA = landscape acreage

Landscape irrigation potable and recycled water rates beginning July 1, 2026

*1 CCF = 748 gallons

View the full list of IRWD water rates, service charges, and fees on our main Rates and Charges page.

A pumping surcharge is added for customers in locations that cause IRWD to incur additional pumping costs to supply their water.
The surcharge is based on the actual prevailing energy costs and varies depending on the cost to pump water to the area served.
In 2023, IRWD completed a pumping surcharge cost-of-service study, resulting in changes to pumping surcharge areas and costs for some customers.
If you live in an area affected by a pumping surcharge, it is itemized on your monthly water bill.
Click these links to see pumping surcharge maps with associated charges for drinking water (potable) and recycled water (non-potable).