Concord, Massachusetts

• Acton
• Boxborough
• Lincoln
• Maynard
  
• Stow
• Sudbury
• Wayland

Septic System Design...

Who can design septic systems?

The Massachusetts State Environmental Code, Title 5 (310 CMR 15.000) requires that all systems with a design flow greater than 2000 gallons per day be designed by a Massachusetts Registered Professional Engineer.

Although smaller systems are not required by law to be designed by an Engineer, the homeowner should carefully consider the wisdom of entrusting the design of a septic system that is likely to cost between $15,000 and $45,000 to anyone other than an experienced, properly licensed Professional Engineer.

Soil Testing

Soil testing is the first step in designing a new septic system — it determines how large the system must be and how deep in the ground the system can be placed. State regulations require that soil testing be performed by a licensed Soil Evaluator and that the testing be witnessed by an agent for the local Board of Health.

Perley Engineering will arrange for an excavating company to provide a backhoe to excavate deep test holes for soil evaluations (usually 9 to 12 feet deep) and scratch holes for percolation tests.

Deep test holes are used to determine the class of soil and establish the high groundwater elevation. Percolation tests are used to estimate the permeability of the soil.

For a Repair or Upgrade (where the new system will have the same or smaller capacity than the existing system), testing usually only needs to be performed in the area where the new leaching field will be constructed.

For New Construction (for a new house or for a system with an increased  capacity), testing must also be performed in the required Reserve Leaching Area which will be reserved for possible use in the event of a future system failure.

Topographical Survey

After soil testing, Perley Engineering will perform a Topographical Survey of the property to locate significant site features such as buildings, driveways, fences, utilities, wells, trees, wetlands, test holes, etc. as well as obtain elevations in the area where the new system will be built.

Septic System Design & Plan

Using the data obtained during soil testing and the topographical survey, Perley Engineering will design a new septic system and prepare the Proposed Septic System Plan.

The system design will be carefully tailored to the specific situation, taking into consideration the required capacity and site conditions while minimizing costs and disruption to the existing landscaping.The required capacity of the system will be based upon the number of bedrooms in the house.

The size of the system will be based upon the required capacity, the type and permeability of the soil and whether a garbage grinder is installed. The height or depth of the leaching system will depend upon the depth of groundwater at the leaching system.

Review & Approval

Perley Engineering will submit the Proposed Septic System Plan to the Board of Health for review.

Administrative approval by Health Department staff can take up to 45 days. More time may be required if variances to Title 5 or local regulations are needed for the new design and the plan requires approval at a Board of Health meeting, or if there are wetlands nearby and Conservation Commission approval is required.

When the plan has been approved by the Board of Health, a Construction Permit will be issued to the homeowner.

System Installation

In order to construct the system, the homeowner must hire a Licensed Septic System Installer.

Perley Engineering will supply copies of the final plan to send to the installers for prices (most homeowners request three bids). The homeowner may then select an installer and enter into a contract for construction.

Construction may begin as soon as the Construction Permit has been issued, as well as any other necessary permits (such as an Order of Conditions for work near a wetland).

During construction, the Board of Health will usually be on site several times to conduct their inspections to ensure compliance with regulations.

As-Built Plan

After construction of the septic system has been substantially completed, and before it has been backfilled, Perley Engineering will measure the locations and elevations of the septic system components in order to prepare an As-Built Plan.

The As-Built Plan will show the actual location of the completed system, allowing the manholes and inspection ports to be easily located for future maintenance and inspections. Copies of the As-Built Plan will be provided to the homeowner and to the Board of Health.

If everything is satisfactory, the Board of Health will then issue a Certificate of Compliance to the homeowner.