248 Mass. Reg. 10.09

Current through Register 1444, May 28, 2021
Section 10.09 - Interceptors, Separators and Holding Tanks
(1)Interceptors, Separators and Holding Tanks.
(a)Interceptors Required.
1. Interceptors separators, and holding tanks shall be provided to prevent the discharge of oil, gasoline, grease, sand, and other substances that are harmful or hazardous to the building drainage system, the public sewer, sewage treatment plant, sewage treatment processes, or other environmentally sensitive areas.
2. No wastes other than those requiring treatment or separation shall be discharged into any interceptor, separator, or holding tank.
(b)Separation or Containment of Gas, Oil, and Other Petroleum Distillates. For purposes of 248 CMR 10.09(1)(b), a motor vehicle shall be considered a self-propelled road vehicle, commonly wheeled, that include cars, buses, and trucks.
1.Required Locations. A separation or containment system shall be required for any building or structure containing:
a. Motor vehicle parking, repair/maintenance, washing, and storage areas; or
b. Other spaces which are sufficiently large to allow access by motor vehicles.
2.Exceptions. A separation or containment system shall not be required for:
a. Single family residential garages;
b. Multi-family, condominium, and apartment garages which are sufficiently small that they could only hold a maximum of six motor vehicles;
c. Buildings or structures whose floor is unfinished or paved such that the surface is sufficiently porous that any gas, oil, or other petroleum distillates would be absorbed by the surface prior to reaching any separation or containment systems;
d. Buildings or structures that are exclusively classified as a storage group pursuant to 780 CMR: State Board of Building Regulations and Standards which are sufficiently small that they could only hold a single motor vehicle and there is no other plumbing;
e. Showrooms used for the purpose of selling used or new motor vehicles which are located within a structure classified by 248 CMR 10.10(18): Table 1, as a mall (covered) or retail (mercantile) that is open to and used by the public; and
f. Installations where outside permanent bollards or other devices are spaced in front of entrances to the building or structure so as to prevent the entrance of a motor vehicle.
3.Rules for Separation Systems. For use when connecting to a sewer system
a. In general, one of the following separation systems must be utilized:
i. A system meeting the design specifications outlined in 248 CMR 10.22: Figure 15 or such other specifications approved by the Board;
ii. A product accepted separation system;
iii. A separation system designed by a registered professional engineer whereby the engineer prepares all plans and specifications and certifies in writing to the inspector that the installation complies with these plans and specifications; or
iv. for smaller installations involving a maximum of two vehicle bays, a pump connected to a double walled tank, both of which are rated by the manufacturer to hold volatile chemicals, meeting the requirements in 248 CMR 10.09(1)(b)3.a.iv.(i) through (iii):
(i) The tank must hold a minimum of 60 gallons per vehicle;
(ii) The tank must be equipped with a liquid sensor to detect leaks; and
(iii) The tank must be vented through a roof.
b.Approvals of Other Agencies.
i. Where specifically noted, the approval of other agencies may be required in order to complete the installation of a separation system, however, said approvals shall not be deemed to supersede the requirements for a Permit as well as full inspection by the Inspector of all components and connections of a separation system. If the approval of another agency would necessitate a violation of 248 CMR 10.00, 248 CMR 10.00 must be followed unless a variance is granted by the Board.
ii. Connection of a separation system to a sewer shall adhere to Massachusetts Department of Environmental Protection rules located at 314 CMR 7.00: Sewer System Extension and Connection Permit Program.
iii. When in an area governed by the Massachusetts Water Resources Authority (MWRA), notice of the installation of a separation system must be made to the MWRA prior to the issuance of a permit. Thereafter, the installation shall adhere to MWRA rules located at 360 CMR 10.016: Sewer Use.
(2)Grease Traps and Interceptors When Installed Inside of Buildings.
(a) Grease traps and interceptors shall be installed in the following establishments to prevent the discharge of fats, oils, and grease into the drainage system:
1. restaurants;
2. cafeterias;
3. hotels;
4. hospitals;
5. institutional facilities;
6. factories;
7. clubs;
8. bars where food is prepared and served; and
9. all commercial kitchens; food and meat packing and processing establishments; super markets, bakeries, and other establishments where fats, oils and grease may be introduced into the building sanitary drainage system in quantities that can cause waste line obstruction or hinder sewage disposal.
(b) Grease traps and interceptors may be installed on individual fixture waste branches.
(c) Plumbing fixtures to be protected by grease traps and interceptors shall include:
1. pot sinks (with bowl depths exceeding ten inches);
2. scullery sinks (with bowl depths exceeding ten inches),
3. floor drains;
4. floor sinks;
5. automatic dishwashers regardless of temperature;
6. pre-rinse sinks;
7. soup kettles or similar devices;
8. wok stations; and
9. automatic hood wash units;
(d) In unsewered areas refer to 310 CMR 15.00: The State Environmental Code, Title 5: Standard Requirements for the Siting, Construction, Inspection, Upgrade and Expansion of On-site Sewage Treatment and Disposal Systems and for the Transport and Disposal of Septage relative to grease removal at installations from which large quantities of grease can be expected to discharge.
(e)Floor Drain Exception: Floor drains that may encounter grease residue and are specifically designed for this purpose may conduct grease to an outside grease interceptor. Grease interceptors may be installed on a separate building drain and shall only receive the discharge from fixtures or equipment which would allow fats, oils or grease to be discharged to the sanitary drainage system.
(f)Food Waste Grinders and Pre-rinse Sinks.
1. The waste from dishwasher pre-rinse sinks that are not equipped with food waste grinders shall be discharged to the drainage system through a grease trap interceptor.
2. A dishwasher pre rinse sink drain not equipped with a food waste grinder that conveys the waste discharge to a dish washing machine drain as shown in 248 CMR 10.22: Figure 22 shall be a minimum diameter of two inch. The total developed length of the horizontal waste drain from the dishwasher pre-rinse sink outlet to the weir of the dish washing machine trap shall not exceed eight feet.
3. The waste discharge from a commercial food waste grinder (garbage disposal) shall not discharge to the sanitary drainage system through a grease trap. Dishwasher pre-rinse sinks equipped with food waste grinders shall be discharged in accordance with 248 CMR 10.10(8)(b) through (d).
(g)Sizing, Testing and Rating.
1. Grease traps and interceptors shall not be installed unless sized, tested, and certified according to PDI-G101 or ASME A112.14.3 or ASME A112.14.4.
2. Grease traps and interceptors must bear the certification seal of the Plumbing and Drainage Institute (P.D.I.) or AMSE. The Board may authorize the use of alternate design traps and interceptors in accordance with 248 CMR 3.04(2) or (3).
(h)Capacity. Installed grease traps and interceptors shall have a grease retention capacity of not less than two pounds of grease for each G.P.M (gallon-per-minute) of flow,
(i)Flow Control Device.
1. Grease traps and interceptors shall be equipped with flow control devices. A flow control device may be equipped with a vented (air intake) or be of an integral non-vented design. Integral non-vented flow control device shall be placed in accordance with manufacturers' recommendations. A flow control device is required to be installed between the fixture and the grease trap/interceptor in accordance with manufacturers' instructions.
2. The flow control device is designed to regulate the flow and discharge rate of waste water through the trap or interceptor.
3. The vented external flow control device air intake when installed in combination with a Grease Trap, may terminate to the free atmosphere provided it terminates a minimum of six inches above the flood level rim of the fixture(s) being served.
4. The vented external flow control devices when installed in combination with a Grease Interceptor may connect to the sanitary venting system of a building or structure provided that the external flow control and fixture(s) are protected by a trap installed in accordance with all applicable provisions of 248 CMR 10.00.
5. A flow control device will not be required for interceptor/separators that are designed to provide a retention capacity of 30 minutes or less.
(j)Water Cooled Interceptors/Separators. The use of water-cooled interceptors/separators is prohibited.
(k)Interceptors Not Required.
1. Grease traps and interceptors are not required for residential building(s), structure(s), dwellings or dwelling units or any private residence.
2. Grease traps and interceptors shall be required in buildings deemed residential that incorporate commercial cooking accommodations.
(l)Treatment Agents and Chemicals. Chemicals, liquids or agents of any type used for the primary purpose of emulsification and separation of grease that by formula allow grease to be transferred or conveyed from the trap or interceptor to the drainage system are prohibited,
1. Grease and accumulated solids shall be removed from traps and interceptors and disposed of in accordance with applicable Federal, State and Local health code requirements by the owner or his or her agent. Federal, State and Local laws, regulations and by-laws may require monitoring and registration of installed traps and interceptors.
2. The local board of health official(s) or similar authority having jurisdiction may require other methods or programs to monitor maintenance of grease traps and interceptors.
3. A laminated sign shall be stenciled on or in the immediate area of the grease trap or interceptor in letters one-inch high. The sign shall state the following in exact language:


This grease trap/interceptor shall be inspected and thoroughly cleaned on a regular and frequent basis. Failure to do so could result in damage to the piping system, and the municipal or private drainage system(s).

(n)Procedures for Sizing Grease Interceptors.
1. Grease traps and interceptors shall be sized in accordance with the following Recommended Procedures For Sizing Grease Interceptor and 248 CMR 10.22: Figure 22.
2.Recommended Procedures and Formulas for Installing Grease Traps and Interceptors. As a general rule it is recommended that traps and interceptors be sized in accordance with the formulas indicated in 248 CMR 10.09: Tables 1 through 3. It is favorable policy to size the interceptor so that its rated capacity is never less than 40% of the individual fixture capacity in gallons. In the example below the actual fixture capacity is 59.8 Gals, and 40% of this would be 23.9 Gals. It is understood that a drainage period other than one or two minutes can be used.

248 CMR 10.09: Table 1:



EXAMPLE (Single Compartment)

STEP 1. Determine the cubic content of the fixture by multiplying length x width x depth, (of each comp)

A sink 48" long by 24" width by 12" deep. Cubic content 48" x 24" x 12" = 13,824 cu. in. or Cubic contents 4' x 2' x 1' x 7.5 Gals. = 60 Gals.

STEP 2. Determine the total capacity in gallons. 1 gallon = 231 cubic inches

Contents in Gallons 13.824/231 = 59.8 Gals.

STEP 3. Determine actual drainage load. The fixture is usually filled to approximately 75% of the capacity with waste water. The items being washed displace about 25% of the fixture content. Actual drainage load = 75% of fixture capacity.

Actual Drainage Load .75 x 59.8 Gals. = 44.9 Gals

STEP 4. Determine the flow rate and the drainage period. In general, good practices dictate a one minute drainage period, however where conditions permit, a two minute period is acceptable. Drainage period is the actual time required to completely empty the fixture.

Calculate flow rate for one minute period. Flow rate 44.9 Gals. 1/min. = 44.9 G.P.M.

For two minute period

Flow rate 44.9 Gals./2min. = 22.5 G.P.M.

STEP 5. Select the interceptor which corresponds to the flow rate calculated Note: Select larger size when flow rate falls between two sizes listed.

NOTE: The example above is representative of acceptable method(s) when purchasing an interceptor based on the total fixture flow rate capacity in gallons. When purchasing an interceptor based on grease retention pounds only, multiply the total gallon flow rate capacity of the fixture by two.

248 CMR 10.09Table 2:



For Restaurants:

Other Establishments with Commercial Kitchens:

(S) X (GS) X (HR/12) X (LF) = Effective Capacity of Grease Traps and Interceptors in Gallons

(M) X (GM) X (LF) = Effective Capacity of Grease Traps and Interceptors in Gallons



S = Number of Seats in Dining Area

GS = Gallons of Waste Water per Seat:

HR = Number of Hours Restaurant Is Open.

LF = Loading Factor

Use 25 Gallons for Restaurants with China Dishes and/or automatic dishwashers

Use 10 Gallons for Restaurants with Paper or Baskets and no dishwashers.

M = Meals Prepared per Day

GM = Gallons of Waste Water per Meal (Use 5 Gallons)

LF = Loading Factor

Use 1.00 with dishwashing machines and 0.75 without dishwashing machine.

Loading Factors:

Use 2.00 Interstate Highway,

Use 1.00 Main Highway,

Use 0.75 Other Highways

Use 1.50 Other Roadways

Use 1.25 Recreational Areas


Total Flow Through Rating (g.p.m)

Grease Trap/Interceptor Retention Capacity (pounds)



























(3)Grease Interceptors Installed Outside of the Buildings
(a)General Requirements for Outside Interceptors. When an outside grease interceptor is installed, the entire installation within the property line shall comply with 248 CMR 10.03, and the installation shall be designed by a registered professional mechanical engineer.
(b) This installation shall require a chamber vent which shall:
1. be piped to the inside of the building in compliance with 248 CMR 10.16(5)(e); and
2. shall be not less than four inch minimum pipe diameter.
(4)Special Use Installations.
(a)Sand Interceptors - Floor Drains.
1. Wherever a floor drain discharges waste to an oil and gasoline separator, the floor drain shall be equipped with an approved sediment and sand control basket, or the floor drain shall discharge through a sand interceptor.
2. Multiple floor drains may discharge into one sand interceptor.
(b)Sand Interceptors - Commercial Establishments. Sand and similar interceptors for heavy solids shall:
1. be so designed and located as to be readily accessible for cleaning; and
2. have a water seal of not less than six inches.
(c)Laundries. Commercial laundries shall be equipped with an interceptor having a wire basket or similar device, removable for cleaning, that will prevent passage into the drainage system of solids ½ inch or larger in size, string, rags, buttons, or other materials detrimental to the public sewerage system.
(d)Bottling Establishments. Bottling plants shall discharge their process waste into an interceptor that provides for the separation of broken glass or other solids, before discharging liquid wastes into the drainage system.
(e)Slaughter Houses. Slaughtering room and dressing room drains shall be equipped with interceptors approved by the Plumbing Drainage Institute which shall prevent the discharge into the drainage system of feathers, entrails, and other materials likely to cause stoppage of the drainage system.

248 CMR 10.09

Amended by Mass Register Issue 1331, eff. 1/27/2017.