1. (a) Subject to (c), below, the design flows for a non-community water system, shall be the maximum daily water use and shall be determined using one or more of the following methods:

   1. (1) Using the values in Table 1008-1 in Env-Wq 1008.03; or
   2. (2) Using historical water use in accordance with (b) below.

2. (b) Historical water use shall be determined using one of the following:

   1. (1) If at least 12 months of consecutive daily water meter readings are available, the water system’s design flow shall be the maximum reported value;
   2. (2) If at least 12 months of consecutive weekly water meter readings are available, the water system’s design flow shall be the daily average value multiplied by 2; or
   3. (3) If at least 12 months of consecutive monthly water meter readings are available, the water system’s design flow shall be the daily average value multiplied by 3.
3. (c) Since the design flows contained in Env-Wq 1008 do not include exterior water use, for those water systems where watering lawns and gardens, filling swimming pools, supplying fire protection systems such as sprinklers, or other high water use demands are expected, additional supply capacity shall be provided, subject to (d) below.
4. (d) The PWS shall be designed for all expected uses. Any uses not accounted for in the design shall be explicitly prohibited.

Source. (See Revision Note at part heading for Env-Dw 406) #10613, eff 6-1-14; ss by #14158, eff 12-25-24 (formerly Env-Dw 406.08)