Massachusetts Title 5 Code Addendum

Modifications to Massachusetts Title 5 Code 

(Approved by the Southborough Board of Health March 28, 2000)

15.223 Septic Tanks

Septic tanks shall have the following capacities:

  • For a single-family dwelling unit, a minimum effective liquid capacity of 200% of the design flow or a minimum hydraulic detention flow of 48 hours, whichever is greater, shall be required. In no case shall the effective liquid capacity of the tank as measured below the outlet invert elevation be less than 1,500 gallons.
  • When designed to serve facilities other than a single-family dwelling unit, and whenever the calculated design capacity is greater than 330 gallons per day, a two-compartment tank or two tanks in series which meet(s) the design criteria specified in 310 CMR 15.203 is required. The minimum effective liquid capacity of each tank in series shall be 200 % of the design flow. In no case shall the effective liquid capacity of each tank be less than 1,500 gallons.
  • Domestic garbage grinders are prohibited.

15.226 Construction of Septic Tanks

(5) All concrete tanks over 2,000 gallons must be manufactured by a member of either: the NCPA (National Concrete Products Association), or PCI (Prestressed Concrete Institute). All manufacturers of tanks (both concrete and synthetic, fiberglass or plastic) must supervise the off-loading and installation of all tanks over 1,500 gallons. The manufacturer must be responsible for the installation, fabrication and assembly on-site, and must be responsible for conducting a vacuum test or water tightness test of each tank; must schedule with the licensed installer, 48 hours in advance, for witnessing by the Board of Health Agent and design engineer and must furnish a certificate of water tightness.

15.227 Placement & Construction of Tees

(7) All outlet tees shall be fitted with an "outlet filter" such as Zabel, Orenco, Polylock or Infiltrator, or equal having an orifice or sieve size such that no solid larger than.125 inch (1/8") can pass through.

Reasons for Adopting Changes to the Massachusetts Title 5 Code

Septic Tanks - Two Compartment, and Outlet Filters (15.223 & 15.227)

The Board of Health examined documents and literature provided to it by the Director of Public Health. Several of these documents were from manufacturers of two-compartment concrete tanks which have been used extensively in other states. Much of this literature was gathered at D.E.P., New England Interstate Water Pollution Control Commission, and Massachusetts Health Officers Association conferences and meetings. The literature convinced the Board Members that a more refined effluent emanated from tanks, which had two or more compartments, and outlet filters. Obviously, greater amounts of solids and scum settling took place in two-compartment chambers.

Because of Southborough's extensive glacial till soils and the vast surface water supply system (Sudbury Reservoir) and its numerous tributaries, the Board is concerned about protecting this valuable asset. Also, the Board feels that sanitary tee outlet filters do provide an early warning system to homeowners and owner-operators who neglect to regularly pump their septic tanks.

Construction of Septic Tanks (15.226)

The Director of Public Health attended a session at the 1999 Annual Massachusetts Health Officers Association Conference and was convinced, after listening to a presentation made by Mr. Chase, of Chase Pre-Cast Concrete Co. that better methods for the construction, placement, and water-tightness of tanks can be assured by the adoption of the above-mentioned regulation. He provided this literature to the Board of Health Members who saw fit to vote for its adoption immediately. In the past, the Board of Health has had problems with licensed installers attempting to seal large concrete tanks. They now feel that through the adoption of this regulation, a better system for guaranteeing the water-tightness of tanks can now be more properly assured.

Modifications to Massachusetts Title 5 Code 

(Approved by the Southborough Board of Health - March 11, 2004)

Percolation Testing

Effective January 1, 2004, the Southborough Board of Health will require at least three percolation tests in areas with percolation test results greater than 30 minutes per inch. Additional tests in both the primary and reserve area shall be required where soil conditions vary such that the Board or its Agent are completely satisfied that the entire area within the soil absorption system percolates between 31 and 60 minutes per inch.

In areas having exposed bedrock outcrops or shallow to bedrock soils, the Approving Authority may require as many Deep Observation Test Holes as necessary to ascertain that the entire proposed SA.S., including ten feet outside the SA.S. in all directions, have a minimum of four feet of naturally occurring pervious soils.


Soil Absorption Systems (S.A.S.) designed using percolation rates between 31 minutes and 60 minutes per inch and for new construction will require the following:

The area between trenches may be designated as system reserve area only where the separation distance between the excavation sidewalls of the primary trenches is at least nine feet.

Modifications to Massachusetts Title 5 Code 

(Approved by the Southborough Board of Health - June 30, 2014)

Mandatory Septic Tank Pumping

Proposed regulation further protecting the public health and the environment by increasing the standards of "subpart D: Inspection and Maintenance of Systems' of the State of Massachusetts, Environmental Code, Title 5: Standard Requirement for the Siting, Construction, Inspection, Upgrade and Expansion of On-Site Sewage Treatment And Disposal Systems for the Transport and Disposal of Septage

Southborough Board of Health hereby under the authority of Massachusetts General Laws (G.L.), Chapter 111, Section 31 enacts a mandatory septic tank (and pump chamber tank if any exist) pumping at the time of a 310 CMR 15.301: system inspection.

Septic tanks as well as pump chamber tanks or compartments must be pumped by a duly licensed septic pumper/hauler. The inspector must then proceed to completely document the various conditions of the septic tank as enumerated in Section 15.302 (2) (e) both before pumping and after pumping.

15:302: Criteria for Inspection

(2) An inspection shall consist of the collection and recording of the following information:

A description of the septic tank including:

  • Approximate age, size, and condition of the tank
  • Distance between bottom of grease / scum layer and the bottom of the outlet baffle
  • Distance between the top of the scum layer and the top of the outlet tee
  • Thickness of the grease / scum layer
  • Depth of the sludge layer and distance from sludge to outlet tee
  • Physical condition of inlet and outlet tees
  • Any evidence of leakage into or out of tank
  • Any evidence of backup of the effluent

Septic Tank pumping at the time of a Title 5 Inspection does not have to be performed if the septic tank has been pumped in the last 6 months preceding the inspection.