1603.7 Above Grade — 2025 California Plumbing Code

Above grade, storage tanks shall be of an opaque material, approved for aboveground use in direct sunlight or shall be shielded from direct sunlight. Tanks shall be installed in an accessible location to allow for inspection and cleaning. The tank shall be installed on a foundation or platform that is constructed to accommodate loads in accordance with the California Building Code .

Exception: Tanks may be installed directly on grade in accor- dance with Section 1601.3.

FIGURE 1603.2 1603.8 Below Grade. Rainwater storage tanks installed below grade shall be structurally designed to withstand antic

NONPOTABLE RAINWATER CATCHMENT SYSTEMS

TABLE 1603.4

MINIMUM WATER QUALITY

APPLICATION	MINIMUM TREATMENT	MINIMUM WATER QUALITY
Car washing	Debris excluder or other approved means in accordance with Section 1603.17, and 100 microns_(100 µm)_in accordance with Section 1603.18 for drip irrigation.	N/A
_Surface,_Subsurface and drip irrigation	Debris excluder or other approved means in accordance with Section 1603.17, and 100 microns_(100 µm)_ in accordance with Section 1603.18 for drip irrigation.	N/A
Spray irrigation where the maximum storage volume is less than 360 gallons_(1363 L)_	Debris excluder or other approved means in accordance with Section 1603.17, and disinfec- tion in accordance with Section 1603.15.	N/A
Spray irrigation where the maximum storage volume is equal to or more than 360 gallons (1363 L)	Debris excluder or other approved means in accordance with Sec- tion 1603.17.	Escherichia coli: < 100 CFU/100 mL, and Turbidity: < 10 NTU
Urinal and water closet flushing, clothes washing, and trap priming	Debris excluder or other approved means in accordance with Section 1603.17, and 100 microns_(100 µm)_ in accordance with Section 1603.18.	Escherichia coli: < 100 CFU/100 mL, and Turbidity: < 10 NTU
Ornamental fountains and other water features	Debris excluder or other approved means in accordance with Section 1603.17.	Escherichia coli: < 100 CFU/100 mL, and Turbidity: < 10 NTU
Cooling tower make-up water	Debris excluder or other approved means in accordance with Section 1603.17, and 100 microns_(100 µm)_ in accordance with Section 1603.18.	Escherichia coli: < 100 CFU/100 mL, and Turbidity: < 10 NTU

For SI units: 1 micron = 1 µm, 1 gallon = 3.785 L

ipated earth or other loads. Holding tank covers shall be capable of supporting an earth load of not less than 300 pounds per square foot (lb/ft [2] ) (1465 kg/m [2] ) where the tank is designed for underground installation. Below grade rainwater tanks installed underground shall be provided with manholes. Below grade storage tanks, located outside of the building, shall be provided with either a manhole not less than 24 inches (610 mm) square or a manhole with an inside diameter of not less than 24 inches (610 mm). Service ports in manhole cov- ers shall be not less than 8 inches (203 mm) in diameter. The manhole opening shall be not less than 20 inches (508 mm) in diameter and located not less than 4 inches (102 mm) above

the surrounding grade. The surrounding grade shall be sloped away from the manhole. Underground tanks shall be ballasted, anchored, or otherwise secured, to prevent the tank from floating out of the ground where empty. The combined weight of the tank and hold down system shall meet or exceed the buoyancy force of the tank.