310 CMR 15.203 - System Sewage Flow Design Criteria

(1) Each component of an on-site subsurface sewage disposal system shall be designed to treat sanitary sewage discharged from all buildings to be served by the system using the System Sewage Flow Design flows set forth at 310 CMR 15.203(2) through (5), except as provided in 310 CMR 15.203(6). Actual water meter data shall not be substituted for the design flow criteria for the activities listed in 310 CMR 15.203(2) through (5) unless pursuant to 310 CMR 15.416. Design flow is equivalent to estimated generated flow for the proposed use plus a factor representing flow variations.

TYPE OF ESTABLISHMENT	UNIT	GALLONS PER DAY	MINIMUM ALLOWABLE GPD FOR SYSTEM DESIGN
(2) RESIDENTIAL
Bed & Breakfast	per bedroom	110	440
Bed & Breakfast	per bedroom	110
with restaurant open to public add	per seat	35	1000
Camp, resident, mess hall, washroom and toilets	per person*	35
Camp, day, washroom and toilets	per person	10
Camp, day, mess hall,	per person	13
washroom and toilets Campground, showers and toilets	per site	90
Family Dwelling, Single including, but not limited to, single family condominiums & cooperatives	per bedroom	110	330**
Family Dwelling, Multiple	per bedroom	110	***
Family Mobile Home Park	per mobile home	300
Motel, Hotel, Boarding House	per bedroom	110
Retirement Mobile Home Park	per site	150
Housing for the Elderly	per two bedroom unit	150****
Work or Construction Camp	per person	50

(6) Facilities other than those listed in 310 CMR 15.203(2) through (5), and nonresidential facilities with unique design features that result in significantly different design flows than those listed above may apply to the Department for a determination of design flow using actual meter readings of established flows from existing or similar installations without the need for a variance pursuant to 310 CMR 15.410 or 15.416. Prior to making a determination the Department will consult with the local Approving Authority. For state and federal facilities, the Department may also establish system design flows other than those listed above using actual meter readings of established flows from existing or similar installations. Any design flow established by the Department pursuant to 310 CMR 15.203(6), shall be based on 200% of average water meter readings in order to assimilate maximum daily flows or on other methods determined to be appropriate by the Department.

(7) In schools, flows generated from sinks or other drains receiving wastes from science laboratories, graphics arts classrooms, or vocational school activities, including, but not limited to, automotive repair painting, or metal fabrication are classified industrial wastes and shall be directed pursuant to an appropriate permit, to a sewer, if a sewer connection is feasible and, if not, then to an industrial waste holding tank in accordance with 314 CMR 18.000: Industrial Wastewater Holding Tank and Container Construction, Operation, and Record Keeping Requirements or an approved hazardous waste collection receptacle.

Notes

310 CMR 15.203

Amended by Mass Register Issue 1321, eff. 9/9/2016. Amended by Mass Register Issue 1499, eff. 7/7/2023. Amended by Mass Register Issue 1501, eff. 7/7/2023.