1. (a) All irrigation schedules shall be developed, managed, and evaluated to utilize the minimum amount of water required to maintain plant health and prevent water waste. Irrigation schedules shall meet the following criteria:

   1. (1) Irrigation scheduling shall be regulated by automatic irrigation controllers.

   2. (2) Parameters used to set the automatic irrigation controller shall be developed and submitted with the Certificate of Completion for each of the following:

      1. (A) the plant establishment period;
      2. (B) the established landscape; and
      3. (C) temporarily irrigated areas.

   3. (3) Each irrigation schedule shall consider for each station all of the following parameters that apply:

      1. (A) irrigation interval (days between irrigation events);
      2. (B) irrigation run times (hours or minutes per irrigation event to avoid runoff and prevent water waste);
      3. (C) number of cycle starts required for each irrigation event to avoid runoff and prevent water waste;
      4. (D) amount of applied water scheduled to be applied on a monthly basis;
      5. (E) application rate setting;
      6. (F) root depth setting;
      7. (G) plant type setting;
      8. (H) soil type;
      9. (I) slope factor setting;
      10. (J) shade factor setting; and
      11. (K) distribution uniformity or irrigation efficiency setting.
   4. (4) Overhead irrigation systems shall be scheduled between 8:00 p.m. and 10:00 a.m., unless weather conditions prevent it. If the local agency or water purveyor has watering windows that are different or longer, the stricter of the two shall apply. Operation of the irrigation system outside the normal watering window is allowed for auditing and system maintenance.

   5. (5) Total annual applied water shall be less than or equal to Maximum Applied Water Allowance (MAWA).

      1. (A) Actual irrigation schedules shall be regulated by automatic irrigation controllers using current reference evapotranspiration data (e.g., CIMIS) or soil moisture sensor data.
      2. (B) For implementation of the irrigation schedule, carefully consider the irrigation run times, emission device, flow rate, and current reference evapotranspiration, so that applied water does not exceed the Estimated Total Water Use.

Note: Authority cited: Sections 65596 and 65596.5, Government Code. Reference: Sections 65593, 65596 and 65596.5, Government Code.

History

1. New section filed 1-2-2025; operative 1-2-2025 pursuant to Government Code section 11343.4(b)(3) (Register 2025, No. 1).