Special requirements for concrete tanks in California
California regulations require tanks to be of impervious construction to prevent the movement of water into or out of the tank. AWWA standards for concrete tanks (AWWA D110 and D115) have an allowable leakage rate for the tank as constructed. Therefore, you must specify tank construction in excess of AWWA standards to achieve a tank in compliance with the regulations.
California regulations require that all potable water contact materials (materials of construction such as concrete or coatings, linings, gaskets, sealants, etc.) must be certified in accordance with ANSI/NSF Standard 61.
The concrete mix must be certified or the tank interior surfaces must be lined to meet NSF certification. NSF certification requirements apply to all contact surfaces, including vapor zone above the top capacity level.
Although the California Code of Regulations requires the water system operator to only use materials and products that are certified for compliance with NSF Standard 61, the AWWA standards for concrete tanks (D110 and D115) do not require the use of NSF 61 certified products.
Therefore, for construction of new tanks, the tank owner must specify that compliance with NSF Standard 61 is required in order to ensure that the tank will comply with California code requirements.
Special Requirements for Bolted Steel Tanks
- Water Storage Tanks