1. (1) General.

   1. (a) equalization storage volume, to satisfy average day demands for water for indoor use and irrigation use,
   2. (b) fire flow storage volume, if the water system is equipped with fire hydrants intended to provide fire suppression water or as required by the local fire code official, and
   3. (c) emergency storage, if deemed appropriate by the water supplier or the Director.

   Each public water system, or storage facility serving connections within a specific area, shall provide:

2. (2) Equalization Storage.

   1. (a) All public drinking water systems shall provide equalization storage. The amount of equalization storage varies with the nature of the water system, the extent of irrigation use, and the location and configuration of the water system.

   2. (b) Table 510-4 lists required equalization storage for indoor use. Storage requirements for non-community systems not listed in this table shall be determined by calculating the average day demands from the information given in Table 510-2.

      TABLE 510-4

      Storage Volume for Indoor Use

      Type Volume Required

      (gallons)

      Community Systems

      Residential;

      per single resident service connection 400

      Non-Residential;

      per Equivalent Residential Connection (ERC) 400

      Non-Community Systems

      Modern Recreation Camp; per person 30

      Semi-Developed Camp; per person

3. a. with Pit Privies 2.5

4. b. with Flush Toilets 10

   1. (c) Where a drinking water system provides water for irrigation use, Table 510-5 shall be used to determine the minimum equalization storage volumes for irrigation. The procedure for determining the map zone and irrigated acreage for using Table 510-5 is outlined in R309-510-7(3).

      TABLE 510-5

      Storage Volume for Irrigation Use

      Map Zone Volume Required

      (gallons/irrigated acre)

      1 1,782

      2 1,873

      3 2,528

      4 2,848

      5 4,081

      6 4,964

   2. (3) Fire Flow Storage.

      1. (a) Fire flow storage shall be provided if fire flow is required by the local fire code official or if fire hydrants intended for fire flow are installed.
      2. (b) Water systems shall consult with the local fire code official regarding needed fire flows in the area under consideration. The fire flow information shall be provided to the Division during the plan review process.
      3. (c) When direction from the local fire code official is not available, the water system shall use Appendix B of the International Fire Code, 2015 edition, for guidance. Unless otherwise approved by the local fire code official, the fire flow and fire flow duration shall not be less than 1,000 gallons per minute for 60 minutes.

   3. (4) Emergency Storage.

      Emergency storage shall be considered during the design process. The amount of emergency storage shall be based upon an assessment of risk and the desired degree of system dependability. The Director may require emergency storage when it is warranted to protect public health and welfare.

   Hotel, Motel and Resort; per unit 75

   Labor Camp; per unit 25

   Recreational Vehicle Park; per pad 50

   Roadway Rest Stop; per vehicle 3.5

   Recreational Home Development (i.e.,

   developments with limited water use);

   per connection (See Note 2 in Table 510-1) 400

KEY: drinking water, minimum sizing, water conservation

Date of Last Change: July 15, 2015

Notice of Continuation: February 10, 2025

Authorizing, and Implemented or Interpreted Law: 19-4-104