Below the surface of your water bill
On the surface, your bill is pretty simple: Use more water and the bill goes up; use less and it goes down. But a lot goes into your water bill. Here’s a deeper look.
The basic components of your water bill include two things: water usage charges and service charges. Water usage charges are variable costs for the amount of water you use. Service charges are fixed costs to recover the expenses of maintaining IRWD’s water distribution infrastructure.
Variable charges
To encourage wise water use, each residence is assigned a monthly water usage budget, which is based on factors such as the number of occupants and size of irrigated area. Check your bill for a breakdown of what your budget is based on. How much you pay for each CCF of water (1 CCF or 100 cubic feet = 748 gallons) depends on whether you stay within your budget.
Rates are broken into four tiers, each assigned a rate based on the actual cost of service that varies according to the water source. Low Volume and Base Rate tiers are for water used within a customer’s budget, which is sourced primarily from lower-cost groundwater and reduces the need to import expensive water from out of state or Northern California. The majority of imported water costs are allocated to Inefficient and Wasteful tiers.
Fixed charges
Your bill also contains fixed charges for water service and sewer service. Water service charges are based on the size of the meter required to provide flow for the property. These charges — to recover IRWD’s fixed infrastructure costs — are assessed whether or not you use water that month.
How your water budget is calculated
Your monthly household water usage budget is the sum of your indoor and outdoor budgets. Together they represent an efficient volume of water to meet your individualized water needs.
Your indoor budget is simple: 50 gallons per person per day (divided by 748 to convert gallons to CCF).
Your outdoor budget is calculated using data from local weather stations: your irrigated landscape area x evapotranspiration (daily plant water loss in cubic inches) x 0.75 ET factor (to account for the fact that at least 40% of your landscape should be drought-tolerant) x 36.3 conversion factor (to convert acre-inches into CCF).
See a graphical equation and breakdown of dollar rates per rate tier in the April issue of Pipelines at IRWD.com/pipelines.
Learn more
Visit IRWD.com/understandmybill for details on current water rates. Visit IRWD.com/services/proposed-rates for rates beginning July 1, 2026. Contact 949-453-5300 or CustomerService@IRWD.com for questions.
