1503.7 Drawings and Specifications. The Authority

Having Jurisdiction may require the following information to be included with or in the plot plan before a permit is issued for a gray water system, or at a time during the construction thereof: (1) Plot plan drawn to scale and completely dimensioned,

showing lot lines and structures, direction and approxi

Exception: It is not the intent of this section to require that all gray water must be handled by an irrigation field or dis- posal field. It is acceptable for excess gray water to be diverted to the building sewer through a diverter valve or overflow drain as permitted in this chapter.

1503.8.1 Residential Occupancies. The gray water discharge for residential occupancies shall be calculated by water use records, calculations of local daily per person interior water use, or the following procedure: (1) The number of occupants of each dwelling unit shall

be calculated as follows:

(1) Plot plan drawn to scale and completely dimensioned,

showing lot lines and structures, direction and approximate slope of surface, location of present or proposed retaining walls, drainage channels, water supply lines, wells, paved areas and structures on the plot, number of bedrooms and plumbing fixtures in each structure, location of private sewage disposal system and expansion area or building sewer connecting to the public sewer, and location of the proposed gray water system. (2) Details of construction necessary to ensure compliance

with the requirements of this chapter, together with a full

(1) The number of occupants of each dwelling unit shall

be calculated as follows: First Bedroom 2 occupants Each additional bedroom 1 occupant (2) The estimated gray water flows of each occupant

shall be calculated as follows:

« «

(2) Details of construction necessary to ensure compliance

with the requirements of this chapter, together with a full description of the complete installation, including installation methods, construction, and materials. (3) Details for holding tanks shall include dimensions, struc tural calculations, bracings, and such other pertinent data

(2) The estimated gray water flows of each occupant

shall be calculated as follows: Showers, bathtubs, 25 gallons (95 L) and lavatories per day/occupant Laundry 15 gallons (57 L) per day/occupant (3) The total number of occupants shall be multiplied

by the applicable estimated gray water discharge as

(3) Details for holding tanks shall include dimensions, struc tural calculations, bracings, and such other pertinent data as required. (4) A log of soil formations and groundwater level as

determined by test holes dug in proximity to proposed

1503.8.2.1 Lavatories. Daily discharge from lava- tories may be determined by the following equation:

A log of soil formations and groundwater level as

determined by test holes dug in proximity to proposed irrigation and/or disposal area, together with a statement of water absorption characteristics of the soil at the proposed site as determined by approved percolation tests. Exceptions: (1) The Authority Having Jurisdiction shall permit the

use of Table 1504.2 instead of percolation tests.

(3) The total number of occupants shall be multiplied

by the applicable estimated gray water discharge as provided above and the type of fixtures connected to the gray water system. 1503.8.2 Commercial, Industrial, and Institu-tional Occupancies. The Authority Having Jurisdic- tion may utilize the gray water discharge procedures listed below,, water use records or other documentation to estimate gray water discharge.

(1) The Authority Having Jurisdiction shall permit the

use of Table 1504.2 instead of percolation tests. (2) The Enforcing Agency may waive the requirement

for identification of groundwater level and/or soil

(2) The Enforcing Agency may waive the requirement

for identification of groundwater level and/or soil absorption qualities based on knowledge of local conditions. (3) The absence of groundwater in a test hole three (3)

vertical feet (915 mm) below the deepest irrigation

(Equation 15.1) Occupants X lavatory flow rate X 3

Where: The number of occupants = square footage of the building divided by the occupant load factor from the California Plumbing Code Chapter 4, Table A. Lavatory fixture flow rate, new construction = That from the California Green Building Standards (CAL- Green) Code Section 5.303.2.3 Lavatory fixture flow rate, existing fixtures = Actual flow rate for existing fixtures 3 = Average number of uses per person per day 1503.8.2.2 Showers. Daily gray water discharge from showers may be determined by the following equation:

(Equation 15.2) Number of daily uses X shower flow rate X 5 minutes 1503.8.2.3 Commercial Clothes Washers. Daily gray water discharge from commercial clothes washers may be determined by the following equa- tion:

Where: The number of occupants = square footage of the building divided by the occupant load factor from the California Plumbing Code Chapter 4, Table A. Lavatory fixture flow rate, new construction = That from the California Green Building Standards (CAL- Green) Code Section 5.303.2.3 Lavatory fixture flow rate, existing fixtures = Actual flow rate for existing fixtures 3 = Average number of uses per person per day 1503.8.2.2 Showers. Daily gray water discharge from showers may be determined by the following equation:

(3) The absence of groundwater in a test hole three (3)

vertical feet (915 mm) below the deepest irrigation or disposal point shall be sufficient to satisfy this section unless seasonal high groundwater levels have been documented to rise to within this area. (5) Distance between the plot and surface waters such as

lakes, ponds, rivers or streams, and the slope of the plot

(5) Distance between the plot and surface waters such as

lakes, ponds, rivers or streams, and the slope of the plot and the surface water, wherein close proximity. charge.1503.8 Procedure for Estimating Gray Water Dis- Gray water systems shall be designed to distribute the total amount of estimated gray water on a daily basis. The water discharge for gray water systems shall be determined in accordance with Section 1503.8.1 or Section 1503.8.2.

2019 CALIFORNIA PLUMBING CODE 315

ALTERNATE WATER SOURCES FOR NONPOTABLE APPLICATIONS any other purpose or distributed to any other persons or parties.

(Equation 15.3) Cubic feet of capacity X Water Factor X 6

(7) Surge tank shall be structurally designed to with stand anticipated earth or other loads. Surge 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. (8) Where a surge tank is installed underground, the sys tem shall be designed so that the tank overflow will

(7) Surge tank shall be structurally designed to with stand anticipated earth or other loads. Surge tank

Where: Water Factor = Gallons per cubic foot 6 = Average number of uses per day Note: Cubic feet of capacity and Water Factor are con- tained in product specifications or are available from the washer manufacturer. 1503.8.3 Daily Discharge. Gray water systems using tanks shall be designed to minimize the amount of time gray water is held in the tank and shall be sized to dis- tribute the total amount of estimated gray water on a daily basis. Exception: Approved on-site treated nonpotable gray water systems.