G 9 - Surge Tank Constructions (Figures 1, 2, 3 and 4)  

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  • (a)

    Plans for surge tanks shall be submitted to the Administrative Authority for approval. The plans shall show the data required by the Administrative Authority and may include dimensions, structural calculations, and bracing details.


    Surge tanks shall be constructed of solid, durable materials, not subject to excessive corrosion or decay, and shall be watertight.


    Surge tanks shall be vented as required by Chapter 9 of this Code and shall have a locking, gasketed access opening, or approved equivalent, to allow for inspection and cleaning.


    Surge tanks shall have the rated capacity permanently marked on the unit. In addition, GRAYWATER IRRIGATION SYSTEM, DANGER—UNSAFE WATER shall be permanently marked on the surge tank.


    Surge tanks installed above ground shall have a drain and overflow, separate from the line connecting the tank with the irrigation fields. The drain and overflow shall have a permanent connection to a sewer or to a septic tank, and shall be protected against sewer line backflow by a backwater valve. The overflow shall not be equipped with a shutoff valve.


    The overflow and drain pipes shall not be less in diameter than the inlet pipe. The vent size shall be based on the total graywater fixture units, as outlined in Table 7-3 or local equivalent. Unions or equally effective fittings shall be provided for all piping connected to the surge tank.


    Surge tanks shall be structurally designed to withstand anticipated loads. Surge tank covers shall be capable of supporting an earth load of not less than 300 pounds per square foot (14.4k N/m ) when the tank is designed for underground installation.


    Surge tanks may be installed below ground in a dry well on compacted soil, or buried if the tank design is approved by the Administrative Authority. The system shall be designed so that the tank overflow will gravity drain to a sanitary sewer line or septic tank. The tank must be protected against sewer line backflow by a backwater valve.




    Surge tanks shall meet nationally recognized standards for nonpotable water and shall be approved by the Administrative Authority.


    Steel surge tanks shall be protected from corrosion, both externally and internally, by an approved coating or by other acceptable means.

(Ord. 95-0069 § 10 (part), 1995.)