Cal. Code Regs. tit. 23, § 968
(5) The standard for newly constructed residential landscapes (Snew) shall be a landscape efficiency factor of 0.55.
(b)(1) Each year, an urban retail water supplier shall calculate its budget for efficient residential outdoor water use (Routdoor), in gallons, by multiplying the applicable standard (Soutdoor) described in subdivision (a) by the square footage of the most current available residential landscape area (RLA) as described in subdivision (b)(2) or (b)(3), net reference evapotranspiration (Net ET0), and a unit conversion factor of 0.62. This formula is expressed mathematically as follows:
Routdoor = Soutdoor x RLA x Net ET0 x 0.62
(2) Until updated residential landscape area data are available pursuant to paragraph (3), residential landscape area shall be, for each supplier:
(B) If the supplier's actual urban water use for the reporting year, calculated in accordance with Water Code section 10609.22, is greater than the urban water use objective calculated pursuant to section 966 without inclusion of Irrigable Not Irrigated area, a supplier may include:
(A)(i) The supplier's unique square footage of Irrigable Irrigated area included in the Landscape Area Measurements Project update released by the Department on December 6, 2023. After the effective date of this section, a supplier may adjust this value by adding the residential parkway area provided by the Department that the supplier has confirmed is associated with a residential service connection; or
(3) Residential landscape area shall be, for each supplier, the most current updated Irrigable Irrigated area:
(C) Provided by an entity other than the Department or a supplier according to the following criteria:
(5) Notwithstanding subdivisions (b)(2) and (b)(3), a supplier may subtract landscape area that has been categorized as residential but that the supplier has identified as Commercial, Industrial, or Institutional (CII). If the area consists of CII landscapes with dedicated irrigation meters, it shall be included in a supplier's objective pursuant to section 969.
(c)(1) Notwithstanding subdivision (b)(1), an urban retail water supplier may calculate its residential outdoor water use budget (Routdoor), in gallons, by subtracting the square footage of residential special landscape areas (RSLA) from the square footage of the most currently available residential landscape area (RLA) as defined in subdivision (b)(2) and multiplying the result by the applicable standard (Soutdoor) described in subdivision (a); then, by adding that value to the product of the standard for residential special landscape areas (SRSLA) as described in subdivision (a)(4) and the square footage of residential special landscape areas (RSLA); and lastly, by multiplying that sum by net reference evapotranspiration (Net ET0) and a unit conversion factor of 0.62. This formula is expressed mathematically as follows:
Routdoor = (Soutdoor x (RLA - RSLA) + SRSLA x RSLA) x Net ET0 x 0.62
(d) If not included as a variance pursuant to subdivision (g)(3), an urban retail water supplier may add to its residential outdoor budget calculated pursuant to subdivisions (b)(1) or (c)(1) the volume of water associated with residential agricultural landscapes. The budget for residential outdoor water use associated with residential agricultural landscapes (RAg), in gallons, is calculated by multiplying a unit conversion factor of 0.62 by the standard for residential special landscape areas (SRSLA) described in subdivision (a)(4) and by the values provided by the Department for the following parameters: the square footage of residential agricultural landscapes (LAAg) and the net reference evapotranspiration for the aggregated growing seasons associated with the crops grown on residential agricultural landscapes (Net ET0 Ag). This formula is expressed mathematically as follows:
(2) The existence of newly constructed residential landscape area shall be demonstrated by using:
(iii) Measurements of newly constructed residential landscapes collected using accurate remote sensing methods.
(f)(1) An urban retail water supplier may annually, in calculating its urban water use objective, include budgets for variances for residential outdoor water use as follows:
(2) Variances may be requested for water use associated with any of the following:
RAg = SRSLA x LAAg x Net ETO Ag x 0.62
(e)(1) An urban retail water supplier may add to its residential outdoor budget calculated pursuant to subdivision (b)(1) or (c)(1) the volume of water associated with newly constructed residential landscapes. The budget for residential outdoor water use associated with newly constructed residential landscapes (Routdoor, new), in gallons, is calculated by multiplying the standard (Snew) described in subdivision (a)(5) by the square footage of the supplier's newly constructed residential landscape area (RLAnew) as described in subdivision (e)(2), net reference evapotranspiration (Net ET0), and a unit conversion factor of 0.62. This formula is expressed mathematically as follows:
Routdoor, new = Snew x RLAnew x Net ET0 x 0.62
(g) Variances available pursuant to subdivision (f) shall be calculated as follows:
(1) A variance for water use associated with horses and other livestock (Vlivestock), shall be calculated as the sum of water allocations for each animal type-class (T). The water allocation for an animal type-class shall be calculated by multiplying the daily water use of the animal type-class (VT), as specified in paragraphs (A) through (D), by the number of animals (NT), by the average number of days per year where water is provided to the animal type (DT). This formula is expressed mathematically as follows:
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(2) A variance for water use associated with dust control on horse corrals or other animal exercise arenas (Vcorral) shall be calculated by multiplying the square footage of corrals or other animal exercise arenas (Acorral) by the number of days per year the corrals or other animal exercise arenas may be watered (NW) pursuant to paragraph (B), by 0.021 feet of water per water day, and then by 7.48 gallons per cubic foot. This formula is expressed mathematically as follows:
(B) The number of days per year that corrals or other animal exercise arenas (NW) may receive a water budget varies by climate zone as follows:
Vcorral = Acorral xNW x 0.021 x 7.48
(3) A variance for water used to irrigate residential agricultural landscapes (VAg) shall be calculated by multiplying a unit conversion factor of 0.62 by the values provided by the Department for the following parameters: the landscape efficiency factor (LEFAg) as described in paragraph (B), the square footage of residential agricultural landscapes (LAAg), and the net reference evapotranspiration for the aggregated growing seasons associated with the crops grown on residential agricultural landscapes (Net ET0 Ag). This formula is expressed mathematically as follows:
(A) Notwithstanding subdivision (f)(1)(B), if a supplier is using crop-specific landscape area, then the supplier may, in calculating its residential outdoor budget, include an approved variance for water used to irrigate residential agricultural landscapes if the associated water use for this variance represents 1 percent or more of the budget associated with the standard described in section 966(c)(2). A supplier using crop-specific landscape area shall calculate a variance for water used to irrigate residential agricultural landscapes (VAg) by multiplying the square footage of the landscape area used for each crop (LAcrop) by each crop's unique efficiency factor (EFcrop) described in paragraph (C), by the net reference evapotranspiration associated with each crop's growing season (Net ET0 crop), and by a unit conversion factor of 0.62; and then summing the products for each crop. This formula is expressed mathematically as follows:
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VAg = LEFAg x LAAg x Net ETO Ag x 0.62
(4) A variance for water used to respond to a state or local emergency declared in accordance with Government Code section 8558(b) or 8558(c), not including a drought, shall be equal to the volume of water used to respond to the emergency event.
(B) This variance shall not include water reported to the Board supporting a variance for unexpected adverse conditions pursuant to section 985.
(i) The landscape efficiency factor (LEFA) for landscapes using recycled water with TDS concentrations between 900 and 1,600 milligrams per liter (mg/L) shall be calculated by multiplying 0.000371 by the difference between the TDS concentration, in mg/L, of the applied recycled water and 900. This formula is expressed mathematically as follows:
LEFA = 0.000371 x (Concentration of recycled water -- 900)
(5)(A) A variance for the volume of water associated with landscapes irrigated with recycled water containing high levels of TDS (VHTDS) shall be calculated by multiplying the applicable landscape efficiency factor (LEFA) described in paragraph (i) or (ii) by the square footage of the landscape area irrigated with recycled water containing high levels of TDS (LAHTDS), by net reference evapotranspiration (Net ET0), and by a unit conversion factor of 0.62. This formula is expressed mathematically as follows:
VHTDS =LEFA x LAHTDS x Net ET0 x 0.62
(B) Notwithstanding subdivision (f)(1)(C), a supplier may include a variance for water used to irrigate landscapes with recycled water containing high levels of TDS for which the sum of the associated water use calculated pursuant to this paragraph and section 969(e)(2)(B) represents 1 percent or more of the sum of budgets described in section 966(c)(2) and (c)(3), if the supplier is using detailed plant based leaching requirements. A supplier using detailed, plant based leaching requirements shall calculate a variance for water used to irrigate landscapes with recycled water containing high levels of TDS (VHTDS) by subtracting one from the applicable landscape efficiency factor (LEFB) described below and multiplying the difference by the square footage of the landscape area irrigated with recycled water containing high levels of TDS (LAHTDS), net reference evapotranspiration (Net ET0), and a unit conversion factor of 0.62. This formula is expressed mathematically as follows:
(i) The landscape efficiency factor (LEFB) for recycled water applied via sprinkler systems shall be calculated by dividing the plant factor (PF) described in paragraph (iii) by the product of an irrigation efficiency factor of 0.75 and the difference between one and the plants' leaching requirement (LR) described in paragraph (iv). This formula is expressed mathematically as follows:
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(ii) The landscape efficiency factor (LEFB) for recycled water applied via drip irrigation systems shall be calculated by dividing the plant factor (PF) as described in paragraph (iii) by the product of an irrigation efficiency factor of 0.81 and the difference between one and the plants' leaching requirement (LR) as described in paragraph (iv). This formula is expressed mathematically as follows:
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(iv) The leaching requirement (LR) shall be equal to the salinity of the recycled water measured as electrical conductivity (ECiw), in dS/m, divided by the difference between the product of 5 and the plant's salinity threshold measured as electrical conductivity (ECe), in dS/m, and the salinity of the recycled water measured as electrical conductivity (ECiw), in dS/m. ECiw shall be capped at the equivalent of 1,600 mg/L. This formula is expressed mathematically as follows:
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VHTDS = (LEFB -- 1) x LAHTDS x Net ET0 x 0.62
(C) Suppliers delivering recycled water with high levels of TDS for landscape irrigation shall only be eligible for the variance if the following conditions are met:
(6) A supplier may include a variance for water use associated with ponds and lakes for sustaining wildlife, if the pond or lake is required to be maintained by regulation or local ordinance. A variance for water associated with ponds or lakes required to be maintained by regulation or local ordinance (Vwildlife) shall be calculated by multiplying 1.1 by the square footage of applicable ponds and lakes, by reference evapotranspiration less annual precipitation, and by a unit conversion factor of 0.62. This formula is expressed mathematically as follows:
(A) A supplier may, for each reporting year, use an alternative data source for annual precipitation, if it demonstrates to the Department, in coordination with the Board, that the data are equivalent, or superior, in quality and accuracy to the data provided by the Department. Alternative data pursuant to this paragraph shall be reported pursuant to section 975.
(7)(A) Beginning July 1, 2040, a supplier may include a variance for water use associated with the irrigation of existing residential trees. This variance (VR-trees), in gallons, shall be calculated by multiplying the square footage of existing residential trees (AR-trees), by 0.08, by net reference evapotranspiration (Net ET0), and by a unit conversion factor of 0.62. This formula is expressed mathematically as follows:
VR-trees = AR-trees x 0.08 x Net ET0 x 0.62
(C) A supplier shall only be eligible for the variance for existing residential trees if the following conditions are met:
(iii) The supplier submits, as an attachment to its annual report required by section 975(a), a link to, or an electronic copy of, the urban forest management plan or plans covering the supplier's service area and a description of efforts to prioritize water for existing residential trees, as described in subdivision (j); leverage regional and local partnerships to support the installation and maintenance of climate-ready landscapes; and expand green infrastructure, such as swales or rain gardens, to help meet tree irrigation needs.
(h)(1) An urban retail water supplier may, in calculating its annual urban water use objective, include budgets for temporary provisions for residential outdoor use if the supplier submits supporting information meeting the criteria described in subdivision (j).
Vwildlife=1.1 x Ponds and Lakes Area x (ET0 -- Annual Precipitation) x 0.62
(2) Temporary provisions may be requested for water use associated with any of the following:
(i) Temporary provisions available pursuant to subdivision (h) shall be calculated as follows:
(1) A temporary provision for the volume of water associated with planting climate-ready trees (Prtrees) shall be calculated by multiplying the number of newly planted climate-ready trees (Ntrees) by 4 square feet, by the number of days per year the newly planted climate-ready trees may be watered (NW) pursuant to paragraph (C), by 0.85, by net reference evapotranspiration (Net ET0), and by a unit conversion factor of 0.62. This formula is expressed mathematically as follows:
(C) The number of days per year that newly planted climate-ready trees (NW) may receive a water budget varies by climate zone as follows:
Prtrees=(Ntrees x 4) x NW x 0.85 x Net ET0 x 0.62
(2) A temporary provision for the volume of water associated with the establishment of qualifying landscapes (Prland) as described in paragraph (A), shall be calculated by multiplying the square footage of the qualifying landscapes (LAland) by 0.85, by net reference evapotranspiration (Net ET0), and by a unit conversion factor of 0.62. This formula is expressed mathematically as follows:
Prland=LAland x 0.85 x Net ET0 x 0.62
(j) In order to receive approval for either a variance or a temporary provision, an urban retail water supplier must submit to the Board in a machine-readable format for review and approval by the Executive Director, or the Executive Director's designee, a request that includes information quantifying and substantiating each request; information demonstrating that the water applicable to the request is water delivered by the supplier; information verifying that the approval of the request would not jeopardize the ability of a permittee within the supplier's service area to comply with existing permit requirements; information describing and supporting the methodology the supplier will use to estimate the parameters described in section 968(f) and 968(h); and a description of efforts to prioritize water for existing trees, including, but not limited to service-area wide rebate, direct install, and educational programs focused on transitioning to irrigation systems that promote deep and healthy root growth. Such irrigation systems include but are not limited to soaker hoses, deep drip watering stakes, drip tubing, and emitters.
(a)(1) Through June 30, 2035, the standard for efficient residential outdoor use (Soutdoor) shall be a landscape efficiency factor of 0.80.
Note: Authority cited: Sections 1058 and 10609.2, Water Code. Reference: Article X, Section 2, California Constitution; Section 3080, Civil Code; Sections 8558 and 51201, Government Code; and Sections 102, 104, 105, 350, 1122, 1123, 1124, 1846, 1846.5, 10608.12, 10609.2 and 10609.6, Water Code.
1. New section filed 9-30-2024; operative 1-1-2025 (Register 2024, No. 40). For prior history, see Register 87, No. 10.