How are residential water budgets calculated?

Western's customers are provided with a total monthly water budget. The total monthly water budget includes a customer's indoor water budget (Tier 1) and outdoor water budget (Tier 2). The number of billing units in your total monthly water budget varies each month depending on days within the billing cycle and local weather information. Therefore, customers may receive a higher water budget during longer billing cycles and also in the warmer summer months.

  1. Indoor Water Budget
  2. Outdoor Water Budget

Indoor Water Budget

The indoor budget is calculated using four factors:

  • The number of people in the household
  • The average amount of water an efficient person uses daily
  • The number of days in the billing cycle
  • A conversion factor from gallons to billing units


For example, for a 3-person household during a 30-day billing cycle the indoor water budget would be:

Indoor water budget = 3 X 60 X 30 = 5,400 gallons of water / 748 gallons = 7.2 billing units

People per household

Based on census data, Western uses a default number of three people per household for single-family homes and two people per household for condominiums and apartments. The number of people regularly living in your home directly impacts your indoor water budget. If you need to update the number of people in your home, complete the Standard Request for Water Budget Adjustment Form (Spanish).

Average daily water use

Studies show that, on average, a typical person uses less than 60 gallons of water each day indoors. This amount includes all indoor water use such as hydration, bathing, doing laundry, and more while using common water-efficient devices, including low-flow toilets and showerheads. Based on this data, and a review of our customers’ historical water use, Western uses an indoor water budget of 60 gallons per person per day.

Days in the billing cycle

The number of days that you are being billed for service. This information can be located on your bill and comes from the actual dates your meter is read. It may differ from bill to bill, but will usually be between 28 and 31 days.