Section 968 - [Operative 1/1/2025] Outdoor Residential Water Use Standard(a)(1) Through June 30, 2035, the standard for efficient residential outdoor use (Soutdoor) shall be a landscape efficiency factor of 0.80.(2) Beginning July 1, 2035, and through June 30, 2040, the standard for efficient residential outdoor use shall be a landscape efficiency factor of 0.63.(3) Beginning July 1, 2040, the standard for efficient residential outdoor use shall be a landscape efficiency factor of 0.55.(4) The standard for efficient residential outdoor use for residential special landscape areas shall be a landscape efficiency factor of 1.0.(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: Click here to view image
(2) Until updated residential landscape area data are available pursuant to paragraph (3), residential landscape area shall be, for each supplier: (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(ii) For a supplier that has not received residential landscape area data from the Department by the effective date of this section, the supplier's unique square footage of Irrigable Irrigated area shall be what the Department first provides after this section takes effect.(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: (i) Twenty percent of the supplier's unique square footage of Irrigable Not Irrigated area included in the Landscape Area Measurements Project update released by the Department on December 6, 2023; or(ii) For a supplier that has not received residential landscape area data from the Department by the effective date of this section, twenty percent of the supplier's unique square footage of Irrigable Not Irrigated area first provided by the Department after this section takes effect.(3) Residential landscape area shall be, for each supplier, the most current updated Irrigable Irrigated area: (A) Provided by the Department;(B) Updated by a supplier pursuant to paragraph (4); or(C) Provided by an entity other than the Department or a supplier according to the following criteria:(i) The residential landscape area is generated as part of a transparent statewide analysis covering the service areas of all urban retail water suppliers;(ii) Developed with methodologies and procedures that have been demonstrated to the Department to be equivalent, or superior, in quality and accuracy, to those used by the Department to develop residential landscape area; and(iii) Results in landscape area data that have been demonstrated to the Department to be equivalent, or superior, in quality and accuracy to the data included in the Landscape Area Measurements Project update released by the Department on December 6, 2023.(4) A supplier may, for each reporting year, use an alternative data source for reference evapotranspiration, effective precipitation, or its Irrigable Irrigated area, 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 included in the Landscape Area Measurements Project update released by the Department on December 6, 2023. Alternative data pursuant to this paragraph shall be reported pursuant to section 975.(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: Click here to view image
(2) In order to calculate a residential outdoor budget pursuant to this subdivision, a supplier shall demonstrate to the Department, in coordination with the Board, that the landscape areas meet the definition specified in section 965 (aaa). Residential special landscape area data shall be reported pursuant to section 975, and, unless updated by a supplier pursuant to this paragraph, data approved by the Department may be included for up to five years.(3) For the purposes of this subdivision, the square footage of existing pools, spas, and similar water features shall be either (A) the value included in the Landscape Area Measurements Project update released by the Department on December 6, 2023, or any updates thereafter, or (B) alternative data, if the supplier 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.(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: Click here to view image
(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: Click here to view image
(2) The existence of newly constructed residential landscape area shall be demonstrated by using: (i) Data from annual reporting required by section 495(b)(6), provided the report has disaggregated newly constructed residential landscapes from the total landscape area reported;(ii) On the ground measurements of newly constructed residential landscapes; or(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: (A) the supplier submits supporting information meeting the criteria described in subdivision (j).(B) The associated water use must, for any individual variance identified in paragraph (2)(A) through (C), represent 5 percent or more of the budget associated with the standard described in section 966(c)(2).(C) The associated water use for the variances identified in paragraph (2)(D) and in section 969(e)(2)(A), or the associated water use for the variance identified in paragraph (2)(E) and in section 969(e)(2)(B), must represent 5 percent or more of the sum of the budgets associated with the standards described in section 966(c)(2) and (3).(2) Variances may be requested for water use associated with any of the following: (A) Populations of horses and other livestock(B) Controlling dust on horse corrals or other animal exercise arenas(C) Irrigating agricultural landscapes that are within residential areas but have not been classified as irrigable irrigated by the Department(D) Responding to emergency events, not including drought(E) Landscapes irrigated with recycled water containing high levels of TDS(F) Supplementing ponds and lakes to sustain wildlife as required by existing regulations or local ordinances(G) Irrigating existing residential trees.(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: Click here to view image
(A) For sheep, llama, donkey, swine, and other medium-sized livestock between 200 and 500 pounds, the daily water use shall be the lesser of 8 gallons of water per day per animal or the amount specified in section 697.(B) For cattle, bulls, and other livestock greater than 500 pounds, the daily water use shall be 11 gallons of water per day per animal.(C) For horses and mules, the daily water use shall be 13 gallons of water per day per animal.(D) For milking cows, the daily water use shall be 16 gallons of water per day per animal.(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: Click here to view image
(A) The square footage of corrals or other animal exercise arenas in the supplier's service area (Acorral) shall be either the value included in the Landscape Area Measurements Project update released as a separate corral dataset by the Department on December 6, 2023, or any updates thereafter, or alternative data, if the supplier 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.(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:(i) For climate zones 1 through 5 and zone 7, corrals or other animal exercise arenas shall be watered no more than 2 days per week.(ii) For climate zones 6, 8 through 10, 12, and 16, corrals or other animal exercise arenas shall be watered no more than 3 days per week.(iii) For climate zones 11 and 13 through 15, corrals or other animal exercise arenas shall be watered no more than 4 days per week.(iv) If a supplier's service area spans multiple climate zones, the supplier shall, for the purposes of calculating this variance, use the climate zone that covers the majority of the supplier's service area. A supplier may, upon a showing to the satisfaction of the Board, use the climate zone that covers the majority of the square footage of corrals or other animal exercise arenas within the supplier's service area.(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: Click here to view image
(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: Click here to view image
(B) The landscape efficiency factor for residential agricultural landscapes (LEFAg) shall be the annual factor, calculated using data provided by the Department, as the average regional crop coefficient divided by the average regional irrigation efficiency. The average regional crop coefficient for the reporting year will be based on the most recent Statewide Crop Mapping dataset developed by the Department and the most recent crop coefficients identified in the Food and Agriculture Organization of the United Nation's (FAO) Irrigation and Drainage Paper 24 (published in 1977), FAO's Irrigation and Drainage Paper 56 (published in 1998), the University of California Cooperative Extension's (UCCE) Leaflet 21427: Using Reference Evapotranspiration (ET0) and Crop Coefficients to Estimate Crop Evapotranspiration (ETC) for Agronomic Crops, Grasses, and Vegetable Crops (published in 1989), or UCCE's Leaflet 21428: Using Reference Evapotranspiration and Crop Coefficients to Estimate Crop Evapotranspiration for Trees and Vines (published in 1989), which are hereby incorporated by reference. The irrigation efficiency shall be based on the Application Efficiency: Hydrologic Region 2010 values developed by the University of California (UC) Davis Water Management Research Group that are located in the Research Report: Spatial Analysis of Application Efficiencies in Irrigation for the State of California (published in June 2013), hereby incorporated by reference, or a comparable tool if the supplier demonstrates to the Department that the tool is equivalent, or superior, in quality and accuracy.(C) Each crop's unique efficiency factor (EFcrop) shall be calculated as the crop coefficient divided by efficiency of the irrigation system associated with that specific crop in the supplier's service area. The crop coefficient values shall be the most recent crop coefficients identified in the FAO's Irrigation and Drainage Paper 24 (published in 1977), FAO's Irrigation and Drainage Paper 56 (published in 1998), UCCE's Leaflet 21427: Using Reference Evapotranspiration (ET0) and Crop Coefficients to Estimate Crop Evapotranspiration (ETC) for Agronomic Crops, Grasses, and Vegetable Crops (published in 1989), or UCCE's Leaflet 21428: Using Reference Evapotranspiration and Crop Coefficients to Estimate Crop Evapotranspiration for Trees and Vines (published in 1989). The irrigation efficiency shall be based on Application Efficiency: Hydrologic Region 2010 values developed by the UC Davis Water Management Research Group that are located in the Research Report: Spatial Analysis of Application Efficiencies in Irrigation for the State of California (published in June 2013), or a comparable tool if the supplier demonstrates to the Department that the tool is equivalent, or superior, in quality and accuracy.(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. (A) To be eligible for this variance, a supplier shall provide a copy of the emergency declaration pursuant to Government Code section 8558(b) or 8558(c), official evacuation orders, official incident reports, a document describing or map showing impacted parcels, and records of the total volume of water used as part of the emergency response efforts.(B) This variance shall not include water reported to the Board supporting a variance for unexpected adverse conditions pursuant to section 985.(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: Click here to view image
(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: Click here to view image
(ii) The landscape efficiency factor (LEFA) for landscapes using recycled water with concentrations of TDS equal to or above 1,600 mg/L shall be 0.26.(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: Click here to view image
(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: Click here to view image
(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: Click here to view image
(iii) The plant factor shall be that of the lowest water-using plant that is present in at least 30 percent of the landscaped area.(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: Click here to view image
(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: (i) The facility that produces the recycled water has completed annual volumetric reporting requirements consistent with the Board's Water Quality Control Policy for Recycled Water, Resolution No. 2018-0057 (adopted by the Board on December 12, 2018), which is hereby incorporated by reference;(ii) The application of the recycled water complies with all applicable waste discharge requirements;(iii) The application of the recycled water does not violate the terms of the applicable salt or nutrient management plan;(iv) The application of the recycled water adheres to the Board's Anti-Degradation Policy, Resolution No. 68-16 (adopted by the Board on October 28, 1968), which is hereby incorporated by reference, or any update thereto.(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: Click here to view image
(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: Click here to view image
(B) The square footage of existing residential trees (AR-trees) shall be the square footage of existing residential tree canopy coverage within the supplier's residential landscape area, as described in subdivisions (b)(2) and (3). A supplier must describe and substantiate how the square footage of existing tree canopy was quantified.(C) A supplier shall only be eligible for the variance for existing residential trees if the following conditions are met: (i) The supplier submits to the Board an analysis that quantifies the irrigation needs of existing trees and evaluates how those needs are being met. The analysis shall be based on an inventory of existing trees within the supplier's service area. The inventory must include detailed tree data including but not limited to tree species and tree diameter at breast height for at least 10 percent of trees, or a statistically valid sample. The analysis and inventory must be prepared or validated by a credentialed or certified urban forester or certified arborist.(ii) The supplier submits to the Board an analysis demonstrating that meeting its water use objective pursuant to section 966 would require adhering to the residential outdoor standard identified in section 968(a)(3) and that meeting the budget for efficient residential outdoor use would unavoidably and adversely affect tree health. The analysis must also demonstrate that the supplier cannot meet its water use objective pursuant to section 966 by first taking, incentivizing, or causing other feasible actions, such as the conversion of high-water use landscapes to climate-ready landscapes.(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).(2) Temporary provisions may be requested for water use associated with any of the following: (A) The planting of new, climate-ready trees(B) The establishment of qualifying landscapes.(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: Click here to view image
(A) A climate-ready tree is a tree that can be reasonably expected to survive both present and future climatic challenges such as heat, drought, extreme weather events, and pests within the supplier's service area. Each newly planted climate-ready tree is assumed to occupy 4 square feet.(B) A temporary provision for the volume of water associated with planting climate-ready trees applies for three years, starting with the fiscal year in which the trees were planted.(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:(i) For climate zones 1 through 5 and zone 7, no more than 2 days per week.(ii) For climate zones 6, 8 through 10, 12, and 16, no more than 3 days per week.(iii) For climate zones 11 and 13 through 15, no more than 4 days per week.(vi) If a supplier's service area spans multiple climate zones, the supplier shall, for the purposes of calculating this temporary provision, use the climate zone that covers the majority of the supplier's service area.(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: Click here to view image
(A) Qualifying landscapes are those that require temporary irrigation and are associated with at least one of the following: low-impact development, ecological restoration, and mined-land reclamation projects.(B) A temporary provision for water for the establishment of qualifying landscapes applies for three reporting periods, starting with the fiscal year in which irrigation of the qualifying landscape begins.(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. (1) Approved variances or temporary provisions submitted between July 1 and October 1 may be included in the associated budget for the prior state fiscal year.(2) Approved variances or temporary provisions submitted between October 2 and June 30 may be included in the associated budget for the current state fiscal year.(3) Approved variances and temporary provisions may be included in the associated budget for up to five years. Variance and temporary provision approval constitutes approval of both methodology and data. Unless otherwise specified in section 975, a supplier may use the same data for each year or update the data annually in accordance with the approved variance or temporary provision methodology.Cal. Code Regs. Tit. 23, § 968
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).