1503.0 Gray Water Systems
|MINIMUM HORIZONTAL DISTANCE IN CLEAR REQUIRED FROM||SURGE TANK (feet)||SUBSURFACE AND SUBSOIL IRRIGATION FIELD AND MULCH BED (feet)|
|Property line adjoining private property||5||58|
|Water supply wells4||50||100|
|Streams and lakes4||50||505|
|Sewage pits or cesspools||5||5|
|Sewage disposal field10||5||46|
|On-site domestic water service line||5||5|
|Pressurized public water main||10||107|
For SI units: 1 foot = 304.8 mm
1 Including porches and steps, whether covered or uncovered, breezeways, roofed carports, roofed patios, carports, covered walks, covered driveways, and similar structures or appurtenances.
3 Reference to a 45 degree (0.79 rad) angle from the foundation.
4 Where special hazards are involved, the distance required shall be increased as directed by the Authority Having Jurisdiction.
5 These minimum clear horizontal distances shall apply between the irrigation or disposal field and the ocean mean higher high tide line.
6 Add 2 feet (610 mm) for each additional foot of depth more than 1 foot (305 mm) below the bottom of the drain line.
7 For parallel construction or crossings, approval by the Authority Having Jurisdiction shall be required.
8 The distance shall be permitted to be reduced to 11/2 feet (457 mm) for drip and mulch basin irrigation systems.
9 The distance shall be permitted to be reduced to 0 feet for surge tanks of 75 gallons (284 L) or less.
10 Where irrigation or disposal fields are installed in the sloping ground, the minimum horizontal distance between a part of the distribution system and the ground surface shall be 15 feet (4572 mm).
- 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.
- 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 in accordance with the Authority Having Jurisdiction.
- Details for holding tanks shall include dimensions, structural calculations, bracings, and such other pertinent data as required.
- A log of soil formations and groundwater level as determined by test holes dug in proximity to proposed irrigation area, together with a statement of water absorption characteristics of the soil at the proposed site as determined by approved percolation tests.
Exception: The Authority Having Jurisdiction shall permit the use of Table 1504.2 instead of percolation tests.
- 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.
- The number of occupants of each dwelling unit shall be calculated as follows:
First Bedroom 2 occupants Each additional bedroom 1 occupant
- The estimated gray water flows of each occupant shall be calculated as follows:
Showers, bathtubs, and lavatories 25 gallons (95 L) per day/occupant Laundry 15 gallons (57L) per day/occupant
- 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.
- Surge tanks shall be constructed of solid, durable materials not subject to excessive corrosion or decay and shall be watertight. Surge tanks constructed of steel shall be approved by the Authority Having Jurisdiction, provided such tanks are in accordance with approved applicable standards.
- Each surge tank shall be vented in accordance with this code. The vent size shall be determined based on the total gray water fixture units as outlined in this code.
- Each surge tank shall have an access opening with lockable gasketed covers or approved equivalent to allow for inspection and cleaning.
- Each surge tank shall have its rated capacity permanently marked on the unit. Also, a sign stating GRAY WATER, DANGER — UNSAFE WATER shall be permanently marked on the holding tank.
- Each surge tank shall have an overflow drain. The overflow drains shall have permanent connections to the building drain or building sewer, upstream of septic tanks. The overflow drain shall not be equipped with a shutoff valve.
- The overflow drain pipes shall not be less in size than the inlet pipe. Unions or equally effective fittings shall be provided for piping connected to the surge tank.
- Surge tank shall be structurally designed to withstand 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/ft2) (1465 kg/m2) where the tank is designed for underground installation.
- Where a surge tank is installed underground, the system shall be designed so that the tank overflow will gravity drain to the existing sewer line or septic tank. The tank shall be protected against sewer line backflow by a backwater valve installed in accordance with this code.
- Surge tanks shall be installed on dry, level, well-compacted soil where underground or on a level 3 inch (76 mm) thick concrete slab where aboveground.
- Surge tanks shall be anchored to prevent against overturning where installed aboveground. 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 forces of the tank.