Water Budget 101

EVMWD began using a budget-based rate structure in 2010. Under this system, customers receive a unique water budget designed to meet their needs based on the efficient use of water. The water budget has two parts: indoor and outdoor use. Several factors are considered when calculating a water budget, including property size, amount of landscaped area, weather, and number of residents in the household.

Budget-based rates are fair and equitable. Research and customer feedback have shown that this rate structure reduces demand, effectively communicates the need to conserve and changes water use behavior by rewarding customers who use water efficiently.

EVMWD has updated and simplified its residential rate structure, which has four tiers: Indoor, Outdoor, Inefficient and Excessive. Tier 1 reflects a new, statewide standard for indoor use, which is 55 gallons per person, per day. The structure still utilizes irrigated landscape area and weather conditions for Tier 2, but bases its formula on a per-billing period schedule rather than a monthly schedule for the most accurate account of outdoor water use. Those with medical conditions or other special circumstances can request a variance for a larger allocation. Water use above budget falls in to the Inefficient and Excessive price tiers, which are more expensive because EVMWD pays more to secure this additional water supply.

How are Water Budgets Determined?

Indoor water budgets are based on the number of people in a household, each using 55 gallons of water per day. Outdoor water budgets are calculated using three factors: the amount of landscaped area per lot; the average water lost daily to evaporation and plant transpiration (evapotranspiration); and a plant factor, which is the amount of irrigation required by a plant. (EVMWD uses a plant factor of 0.60, which is the minimum amount of water needed for most turf grasses.) All water used by a residential customer within their assigned indoor and outdoor water budget is billed at the lowest rates.


Indoor Use

Eddie thinks of his family’s water budget as buckets of water they have for efficient use all month. The first bucket is for essential indoor water use, including drinking, cooking and washing.


Outdoor Use

Eddie knows he has limited water in the second tier for outdoor water, and he only uses what he absolutely needs to keep his California-friendly landscaped yard looking good all year.


Inefficient Use

When Eddie has variations in his water use because he has house guests or the kids get a hold of the hose on a hot summer day, he slips into the third tier and pays more for that extra bucket of water.


Excessive Use

If Eddie sees that his water use spills into the excessive bucket, he looks for leaks and more ways to reduce his water use. Eddie can also contact EVMWD for a water audit to investigate why his water use is greater than usual.