Principles of Water Budgets

Water budgets are assigned to all Irrigation Classes. A water budget is a tool to encourage appropriate water use during all seasons. Water budgets assign target usage for each billing cycle. Water budgets are tied to a tiered rate billing structure. Accounts with water budgets are billed accordingly. Accounts that use more water than their assigned budget are billed at a higher tier or tiers than the target usage tier. These higher tiers are referred to as water conservation rates.

Note: Effective January 1, 2010, the bi-monthly Water Budgets for irrigation accounts are being modified according to the 2010 billing cycle dates and updated historical weather data. To obtain a copy of your account's bi-monthly water budgets, e-mail us your account number and service address.

Requirements

(1) Water budgets are based on a property’s irrigated landscape area.

(2) Water budgets are assigned on a per meter basis for sites with more than one meter. The site is responsible for providing Helix staff with a map or description of the landscape areas served by each meter.

Procedure

(1) Budgets are calculated by Helix staff using the formula below in compliance with the Maximum Applied Water Allowance (MAWA) as outlined in California’s Model Landscape Ordinance:

Example, Level I:	LA x ( 0.7 x ETo ) x 0.62
	748
	= Water budget in HCF (1 HCF = 748 gallons)

(a) LA=Irrigated landscape area in square feet

(b) 0.7=ET Adjustment Factor

(c) ETo=Reference Evapotranspiration from the closest CIMIS station (Escondido or Otay Lake) in inches per year

(d) 0.62=Conversion factor (to gallons per square foot)

(e) 1.0=ET Adjustment Factor for schools or public sites with functional use turf (e.g. parks, picnic areas, athletic fields)

(f) The ET Adjustment Factor will be modified as the District Water Shortage Levels change (See Table A below.)

(g) The California Irrigation Management Information System (CIMIS) lists the historical ETo figures online at http://www.cimis.water.ca.gov. Helix water budget calculations will be in compliance with these figures.

(2) Water budgets are calculated on a bi-monthly billing cycle basis.

Compliance

(1) If a customer believes that the assigned budget is too low, given their site conditions, they may apply for a variance to their water budget for potential adjustments to the irrigated landscape area, plant type or other special circumstances approved by the General Manager or his/her designee.

(2) Newly planted low-water-use landscapes (with a crop coefficient of less than 50%) are eligible to apply for an increased water budget during its establishment period not to exceed three years. The watering schedule must be reduced to comply with the site’s standard water budget within three years. All requests are subject to field verification.

3) If the District is unable to confirm a customer's landscaped areas served by each meter, the District will calculate and assign a water budget using 75 percent of the customer's average historical use over the last three calendar years, until such time the required information is provided and confirmed.

4) This policy for assigning water budgets was revised on January 6, 2010.

Table A: Water Shortage Level ET Adjustment Factor

Water Shortage Level	I	II	III	IV
ET Adjustment Factor	0.7	TBD	TBD	TBD

* TBD = To be determined by the Board.

Water Budget Questions?

Water Budget Hotline
(619) 667-6267
or
waterbudget@helixwater.org