GEM PE SSDS Content

The material provided below is intended to be used for general information purposes only and shall not be used as a basis to evaluate, review, investigate or consider the effectiveness or reliability of an existing or proposed septic system. Every effort has been made to provide clear and correct information below. However, Glenn E. Mauk, PE, PLS, Esq. assumes no liability or responsibility for the provided information. Glenn E. Mauk, PE, PLS, Esq. recommends that an experienced Professional Engineer be engaged to advise any party on the condition, requirements, needs or design of a septic system.

In Massachusetts, the design, construction and operation of septic systems are controlled by state and local regulations and by-laws. Volume 310 of the Code of Massachusetts Regulation Section 15 (“310 CMR 15.00”), also known as “Title V” are the state regulations for septic systems. Each town or city can have local regulations or by-laws that can be more, but not less, stringent than Title V. Generally, towns and cities have a “Health Board” or “Board of Health” that are charged with the responsibility of enforcing Title V and any local health regulations at the local level. The Department of Environmental Protection Division of Water, Wastewater and Wetlands (http://www.mass.gov/dep/water/index.htm) has responsibility for promulgation and enforcement of Title V regulations at the state level. For comprehensive information on septic systems refer to local regulations and 310 CMR 15.00 (http://www.mass.gov/dep/service/regulations/310cmr15.pdf). Newly designed septic systems to be constructed to replace a failed septic system (A.K.A. a "repair" septic system) must be designed and constructed in accordance, to the extent possible, with the current version of Title V and any local regulations. An "upgrade" to an older existing septic system, to allow for a building addition to an existing building must comply with all requirements of the current version of Title V and any local regulations. When considering a building addition to an existing building, the owner must understand that although "bedrooms" are used as the basis to determine the necessary size of a septic system, rooms or spaces other than intended "bedrooms" can be counted as the total number of "bedrooms" with a building. See the definition of "bedroom" under 310 CMR 15.002.

A building sewer pipe that conveys sewage from the building to a septic tank. The building pipe is usually made of 4" diameter PVC. The building sewer is sloped form the house to the septic tank with at least 1% pitch.

A septic tank that collects the sewage, allows for separation of the sewage and provides for some initial limited natural treatment of the sewage. The minimum size of a new septic tank for residential use is 1,500 gallons (approximately 10’ long x 6’ tall x 5’ wide). Most septic tanks are made from concrete but septic tanks made from other materials are available. The septic tank is set in the ground level. The inlet pipe is about 3" higher than the outlet pipe.

An outlet pipe that carries septic tank effluent from the septic tank to a distribution box. This pipe is also usually 4" PVC. The slope from the septic tank to the distribution tank is at least 1% pitch.

The distribution box allows the incoming effluent to be divided into 2 or more outlet distribution pipes that carry the effluent to the soil absorption system. The D box is also usually made or concrete. This D Box shown in the below picture has 5 outlet pipes leading to the soil absorption system (also called a leach field, bed, etc.)

The soil absorption system is used to spread the effluent over a large area under the ground surface. The effluent then drains into the underlying soil. On new systems, the lowest part of the soil absorption system must between 4’ and 6’ above the maximum ground water elevation. There are different types of leaching systems. A few of the different types are bed, trench, pit systems. The type of system is generally based on site conditions including water table, percolation rate, topography, property size, etc.

Some septic systems need a pump to "lift" the septic effluent from the septic tank to a leaching system that is higher in elevation from the septic tank. In the picture below, the pump tank is the tank that is furthest away. This pump tank is also 1500 gallons. The second photo is of the pump, wiring and pump piping in the pump tank.

Although not typically required by Title V, unless there is a modification to the approved septic system design plan, most towns require that an "as-built" plan be submitted for installed septic systems. The as-built plan is prepared by the designer of the septic systems and depicts the constructed layout of the subject septic system and sets forth the as-built elevation of the various system components. The plan below is a typical septic system as-built plan.