(A) (1) All nondomestic users shall be required to install and maintain a grease interceptor as specified in this section or when the General Manager and/or, District Engineer or their designee finds that it is necessary for the proper handling of liquid waste containing grease or any other harmful constituents (such as sand or flammable wastes) that may be properly eliminated from the sewage system by use of an interceptor or trap.
(2) An approved type interceptor complying with the provisions of this section shall be installed in the waste line leading from nondomestic kitchen sinks, floor drains, and other kitchen drainage fixtures in the following establishments: restaurants, cafes, lunch counters, cafeterias, bars and clubs; hotels, hospitals, sanitariums, factory kitchens, school kitchens, or other communal use kitchens. If determined necessary by the General Manager or District Engineer, interceptors may also be required in other nondomestic establishments where grease or other harmful constituents (such as sand or flammable wastes) may be introduced into the Sewage system in quantities that can effect line stoppage or hinder Sewage treatment or private Sewage disposal.
(3) All plumbing, traps, and interceptors handling grease laden wastewater shall conform to the requirements of the most recent edition of the California Plumbing Code except where this chapter contains a higher standard than required in the California Plumbing Code. No provisions of this section should be applied as to conflict with existing city or county ordinance, regulation, or code governing plumbing in buildings.
(B) Plans shall be submitted, and approval obtained from the General Manager and/or District Engineer prior to the installation of any grease interceptors or traps in any food establishment set forth in division (A) of this section.
(C) Each gravity grease interceptor required by this section shall have an approved volume not less than that given in Table IV-1. Hydromechanical grease Interceptors shall have an approved volume not less than that provided by calculation in Table IV-2.
(D) All drains from kitchen areas including but not limited to: floor drains, floor sinks, pre-wash sinks, dishwashing sinks, food waste disposal units, dishwashers, and garbage can wash shall be connected to the grease interceptor. Toilets, lavatories and other sanitary fixtures shall not be connected to any grease interceptor. No drains located outdoors shall be connected to the sewer system to comply with § 36.032.
(E) All fixtures discharging into a grease interceptor shall be individually trapped and vented in accordance with the California Plumbing Code. Hydromechanical grease interceptors shall be equipped with a flow control device and venting in accordance with the California Plumbing Code. Grease Interceptors and associated plumbing shall be installed in accordance with grease interceptor manufacturer’s recommendations.
(F) Each grease interceptor shall be so installed and connected that it shall be at all times easily accessible for inspection, cleaning and removal of the intercepted grease.
(G) Interceptors shall be maintained in efficient operating condition by periodic removal of the accumulated grease. No such collected grease shall be introduced into any drainage piping, public or private.
(H) Each grease interceptor shall be constructed of durable materials satisfactory to the General Manager and/or District Engineer and shall have a full-size gas tight cover which can easily and readily be removed.
(I) Any commercial kitchen or food or restaurant establishment that does not have grease interceptors installed in accordance with this section, and the California Plumbing Code, is in violation of the District’s rules and regulations.
(J) Grease interceptors required by this chapter shall not be installed until the type and/or model has been subjected to, and has fully complied with, tests acceptable to the General Manager and/or District Engineer. Where existing conditions are found acceptable as determined by the General Manager and/or District Engineer, such facilities as presently exist will be allowed to remain in use. Whenever it shall come to the attention of the District that any grease interceptor is no longer acceptable or does not comply with the provisions of this section, the General Manager and/or District Engineer shall immediately suspend or revoke such approval and require corrective measure.
(K) Table IV-1.
Drainage Fixture Units (DFU) | Interceptor Volume in Gallons |
(L) Table IV-2. Hydromechanical grease interceptor sizing using fixture capacity.
(1) Step 1: Determine the maximum flow rate from each fixture:
(a) For Sinks: [inches length] x [inches width] x [inches depth] / 231 x 0.75 fill factor / 1 minute drain time = gallons per minute.
(b) The flow rate from non-sink drain fixtures (such as floor drains) shall be determined based on gravity flow rate through fixture drain pipe diameter flowing half full (calculated using Mannings Equation) divided by 2.5.
(2) Step 2: Calculate the total flow rate from fixtures that discharge into the interceptor. Grease interceptor gallons per minute rating shall be equal to or greater than the total load.
Fixtures | Compartments/Qty | Flow Rate (gallons per minute) |
24 inches x 24 inches x 12 inches | 2 | 44.9 |
2” Floor Drain | 1 | 4 |
Rated Appliance | 1 | 5 |
Total | 54 gpm Grease Interceptor | |
Note: GPM = Gallons Per Minute | ||
(3) Step 3: Confirm grease interceptor sizing with manufacturer’s suggested sizing criteria. In the event of a conflict between manufacturer’s suggested sizing and calculation in Step 2, choose the larger size.
(Ord. 2024-02, passed 9-26-2024) Penalty, see § 36.999