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The Water Efficient Landscape Worksheet in Appendix B to Title 23 California Code of Regulations section 429.4 shall be submitted with the Landscape Documentation Package. The worksheet shall be prepared by a landscape architect, civil engineer or architect licensed by the State of California. A homeowner of a single family residence required to submit a water efficient landscape worksheet may prepare their own worksheet, or have a licensed landscape contractor prepare the water efficient worksheet if the homeowner has contracted with that landscape contractor to install the landscaping and irrigation covered by the plan for which the worksheet was prepared. Property owners may also prepare worksheets for any property owned by that person. The water efficient worksheet shall contain all of the following:
(a) Information on the plant factor, irrigation method, irrigation efficiency, and area associated with each hydrozone. Calculations are then made to show that the evapotranspiration adjustment factor (ETAF) for the landscape project does not exceed a factor of 0.42 for residential and non-residential areas, exclusive of Special Landscape Areas.
(1) The ETAF for a landscape project is based on the plant factors and irrigation methods selected, and when applied to reference evapotranspiration, a factor adjusts for plant water requirements and irrigation efficiencies.
(2) The MAWA is calculated based on the maximum ETAF allowed (0.42 for residential and non-residential areas) and shall be expressed in annual gallons.
(3) The Estimated Total Water Use is calculated based on the plants used and irrigation method selected for the landscape design. ETWU shall be expressed in annual gallons and must be below the MAWA.
(b) Water budget calculations shall adhere to the following requirements:
(1) The plant factor used shall be from WUCOLS, or may be obtained from horticultural researchers from academic institutions or professional associations as approved by the California Department of Water Resources. The plant factor ranges from 0 to 0.1 for very low water use plants, 0.2 to 0.3 for low water use plants, from 0.4 to 0.6 for moderate water use plants and from 0.7 to 1.0 for high water use plants. If plants within a hydrozone have different water use requirements the hydrozone category shall be determined using the highest water using plant. Any plant may be selected for the landscape providing the Estimated Total Water Use in the landscape area does not exceed the Maximum Applied Water Allowance.
(2) Temporarily irrigated areas shall be included in the low water use hydrozone. Temporarily irrigated as used in this chapter means the period of time when plantings only receive water until they become established.
(3) The surface area of a water feature shall be included in a high water use hydrozone unless the water feature is a pool or a spa with a durable cover. In that case, the water feature may be included in a moderate water use hydrozone. Pool and spa covers are not required but highly recommended in conserving water due to evaporation.
(4) All Special Landscape Areas shall be identified and their water use calculated as shown on the Water Efficient Landscape Worksheet. The ETAF for new and existing Special Landscape Areas shall not exceed 1.0.