Pressure Dosing and Pressure Distribution

(1) Gravity Distribution. (a) Dosing systems employing gravity distribution to the soil absorption system shall be restricted to systems designed to accept less than 2,000 gpd. (b) The dosing chamber and pumps shall be designed in accordance with 310 CMR 15.231. (c) Distribution lines to the soil absorption system shall have a minimum diameter of two inches and shall otherwise be in conformance with the provisions of 310 CMR 15.251(Trenches). (d) Septic tank effluent shall be dosed to the soil absorption system at a rate based on volume and number of doses that prevent the ponding of the effluent in the soil absorption system. (2) Pressure Distribution. (a) Pressure distribution of septic tank/recirculating sand filter effluent to the soil absorption system shall be required for: a system to serve a facility with a design flow of 2,000 gpd or greater; a system that is not designed to discharge by gravity either from the septic tank or to the soil absorption system; a system designed for intermittent discharge of effluent to the soil absorption system; and a system with a multiple soil absorption system, unless otherwise determined in writing by the Approving Authority. (b) The pumping chamber and pumps shall be designed in accordance with 310 CMR 15.231. (c) The pressure distribution system shall be designed in accordance with Department guidance. (d) Pumps, alarms and other equipment requiring periodic or routine inspection and maintenance shall be operated, inspected and maintained in accordance with the manufacturer's and the designer's specifications. In no instance shall inspection be performed less frequently than once every three months for a system serving a facility with a design flow of 2,000 gallons per day or greater and annually for a system serving a facility with a design flow of less than 2,000 gallons per day. The system owner shall submit the results of such inspections to the Approving Authority annually by January 31st of each year for the previous calendar year.