12 Va. Admin. Code § 5-590-1080

Current through Register Vol. 41, No. 8, December 2, 2024

Section 12VAC5-590-1080 - Basic finished water storage structure design criteria

A. The materials and designs used for finished water storage structures, including associated pipe and valves, shall provide stability and durability as well as protect the quality of the stored water. Steel, concrete, composite, and plastic storage structures shall be designed, constructed, cleaned, disinfected, and tested in accordance with the following AWWA standards, where applicable: D100-11, D103-19, D107-16, D108-19, D110-13, D115-20, D120-19, D121-12, and C652-19.

B. Safety cages, rest platforms, roof-ladder handrails, and other safety devices shall be provided as required by VOSH laws and regulations.

C. Location of finished water storage structures.

1. The bottom of ground-level reservoirs, storage tanks, and standpipes should be placed above finished grade to ensure positive drainage away from the structure.

2. Where the bottom must be below normal ground surface, it shall be placed above the groundwater table. Sewers, drains, standing water, and similar sources of contamination shall be kept at least 50 feet from the finished water storage structure. Pipe conforming to water distribution pipe standards of 12VAC5-590-1110, pressure tested in place without leakage, shall be used for gravity sewers at lesser separations.

3. The top of all storage facilities shall not be less than two feet above the normal ground surface and shall be above the 100-year flood elevation. Any clearwell constructed under filters may be exempted from this requirement when the total design gives the same protection.

D. Pressure variation. The maximum variation between normal operational high and low water levels in finished water storage structures which float on a distribution system shall not exceed 30 feet.

E. Level controls.

1. Adequate controls shall be provided to enable sufficient tank turnover, water quality maintenance, avoidance of overflows, and efficient operations.

2. A telemetery system with recording capability shall be considered to transmit the operating levels in distribution system storage facilities to a location where qualified personnel may access the data at all times.

3. Altitude valves or equivalent controls shall be provided.

4. For tanks with a monitoring system, warnings or alarms indicating overflow, low level, and pump malfunction shall be provided.

12 Va. Admin. Code § 5-590-1080

Derived from VR355-18-011.01 § 3.45, eff. August 1, 1991; Amended, Virginia Register Volume 37, Issue 20, eff. 6/23/2021.

Statutory Authority: §§ 32.1-12 and 32.1-170 of the Code of Virginia.