Landscape Water Budgets

A water budget is a specific amount of water allotted to a property or area of a property, in this case for irrigation purposes. The budget is the amount of water that is calculated for the property in order to keep the landscape in a good healthy condition and to avoid wasteful use.

The water budget is based upon the amount of irrigated area at the property in square feet, as well as other factors including the plant water needs. The calculation is as follows:

{Landscape Area* ETo * Kc * (1/irrigation efficiency)}/100

Landscape Area = the total square feet of irrigated area at the property.

ETo = reference evapotranspiration (in feet). This is the annual depth of water amount that is evaporated and transpired by a reference plant type (fescue grass). The location used for this information is the De Laveaga Golf Course weather station and the annual amount is 3.5 Ft.

Kc= a crop coefficient. This is a factor in the equation that relates to the plant type and how much water each plant type uses. Cool season turf grass uses about 80% of the local ETo while low water use shrubs use approximately 40% of the local ETo. For the purposes of simplifying the equation for all customers, the Kc used here is a blend of shrubs and turf: 0.6.

Irrigation Efficiency (IE): this is a measure of the percent of water applied that is actually used by plants. In other words, the higher the irrigation efficiency, more of the water that is actually applied through an irrigation system gets utilized by plants and is not wasted. The IE used for the budget calculation is 0.7.

The rate structure for irrigation customers is a three-tiered system. The water budget for your account depends on the irrigated square footage and other factors. 

• Usage up to 100% of the water budget is charged at the Tier 1 rates.
• Usage of 101%  to 150% of the budget is charged at the Tier 2 rates.
• Usage over 150% of the budget is charged at the Tier 3 rates. 

For more information on rates, please visit the Rates page.

Your budget for the month can be found on your monthly utility bill for that month. For more information about your monthly budget, utilize the landscape budget calculator at the top of this page or call the Customer Assistance Office at 831-420-5230.

If your usage exceeds the monthly budget, you will be charged in either Tier 2 or Tier 3 depending on how much you exceed your budget.

No. Budgets are assigned per month. If you do not use your full budget for a month, you cannot use extra water the next month.

Yes. If you believe our office has outdated or incorrect information regarding the square footage of irrigated area at your site please call the Water Customer Assistance Office at 831-420-5230.

Please contact the Customer Assistance office at 831-420-5230. We may need to update the square footage information for your site.