Comprehensive Wastewater Management Plan (CWMP) Updates


Sudbury has been investigating wastewater options for the Route 20 Business District for decades. Septic systems have been and continue to be a limiting factor to business expansion and or actual relocation, as well as an environmental concern due to the proximity of these on-site wastewater systems that discharge to the ground near the Town’s Municipal Water Supply wells located on Raymond Road. Additionally, identified high groundwater conditions pose constraints for locating on-site systems in a particular geographic area.
Woodard & Curran, Inc. was contracted by the Town in early 2020 to perform a Town-wide wastewater study called a Comprehensive Wastewater Management Plan (CWMP). This effort is in progress and will continue through late 2021. Woodard & Curran is responsible for reviewing available wastewater needs information including Health Department records and zoning information to determine future uses. The first task included subdividing the Town into Study Areas in order to manage data sets within similar neighborhoods, zoning and geographic areas for evaluation. This work then ultimately affords prioritizing areas of the Town to identify the long-term sustainability of existing on-site wastewater systems (septic) or if an off-site wastewater solution better serves the identified need of environmental resource protection, drinking water protection and preservation, as well as the support of economic development in targeted areas zoned as such. In parallel to the engineering effort, Woodard & Curran, in conjunction with the Town, will be conducting a public outreach campaign in order to fully inform the general public of the work being performed and solicit input into future recommendations. In-person workshops and meetings are currently on temporary hold due to the pandemic, but alternate methods of outreach and education are being developed and will be utilized for outreach to the general public. We are monitoring current conditions and will revise and adapt as appropriate in order to keep the information flowing.

Public outreach efforts may be targeted for groups, such as businesses or neighborhoods that may be considered for public sewer. This website will serve as the centralized location for updated information pertaining to the Project. Monthly updates will be published on this site updating the status of work that has been completed, key decisions or milestones that have been reached, as well as highlight upcoming work/tasks in the pipeline. Outreach meetings and associated content can also be found here and via the Town’s general website.

Feedback / Comments

We welcome your feedback and comments, which you can submit via email to Daniel Nason, DPW Director at [email protected]. We encourage you to provide your thoughts to ensure the wastewater plan is tailored to fit Sudbury now and in the future. Together we build a better plan!

Public Outreach Schedule

In person meetings are currently on hold due to the current status of the COVID-19. All virtual meeting schedules and updates will be posted on this site.


Monthly Project Updates

Background & Supporting Information

  • Ongoing — 2020 Sudbury Master Plan Draft Baseline Report
  • 2013 — (Revised) Project Evaluation Report (PER) by Weston & Sampson Engineers, Inc. (Evaluated Route 20 wastewater options)
  • 2010 — Ponds and Waterways Committee Master Plan
  • 2010 — Route 20 Business District Wastewater Management Plan Update — Weston & Sampson Engineers, Inc.
  • 2004 — Draft Supplemental Nutrient Loading Evaluation of Hop Brook for MassDEP/USACOE by ENSR International. Document No. 09090-042a
  • 2001 — Assessment of Wastewater Management Needs for the Route 20 Business District by Weston & Sampson Engineers, Inc.
  • 1995 — Route 20 Wastewater Disposal Options
  • 1994 — (Revised) Nitrogen Loading Analysis for Groundwater Supplies by H2O Engineering Consulting Associates, Inc.
  • 1989 — Hop Brook Ponds System Study, Sudbury, Massachusetts by Whitman & Howard, Inc.
CWMP Regional Map

Educational Material

The goal of the CWMP is to provide wastewater management alternatives for those properties in need of solutions aside from onsite systems. In general, the following tools/options are commonly used and will likely become part of the recommendations of the proposed town-wide plan.


    Maintain Onsite SystemsOnsite sewage disposal systems most commonly consist of a septic tank where wastewater is partially treated and solids settle to the bottom of the tank. From the septic tank, the partially treated wastewater usually flows to a leaching field where it is dispersed across a larger area and slows percolates into the ground. Flow through this moist (not saturated) area is critical to the final stage of treatment for an onsite system.

    Onsite systems are commonly referred to as Title 5 systems referencing their governing regulation: 310 CMR 15.000: Title 5 of the State Environmental Code. Homes constructed after 1996 are required to be built to the Title 5 standard and are Title 5 compliant. Passing a Title 5 test does not make your system Title 5 compliant, but merely implies that it appears to be functioning satisfactorily. Onsite systems may include a Septage Management Plan where there are maintenance requirements for homeowners where pumping septic tanks may be required annually or bi-annually.


    Innovative / Alternative Systems (I/A Systems) — These systems are located onsite, but include additional forms of treatment and are often associated with sites requiring multiple waivers or in environmentally regulated areas. I/A systems are mostly categorized as General Use (for new or existing construction) and Remedial Use (not for new construction). These systems can be passive or can include more complex series of tanks with pumping steps, mixing, aeration systems etc., which can be quite costly to construct and/or operate.


    Sewer System — A sewer system consists of infrastructure collecting sewage from multiple properties and conveying it to a common treatment location. These systems can be local such a decentralized small Wastewater Treatment Facility (WWTF) – there are three of these identified in-town: Avalon, Longfellow Glen, and the Lincoln-Sudbury High School . Alternatively, the sewer system could be larger and discharge to a WWTF located in an adjacent community or a new facility in Sudbury. Treatment facilities typically discharge to groundwater or surface water, but surface water permits are typically not issued any more so new facilities need to discharge to groundwater, similar to an onsite system. Therefore, an in-Town treatment facility also needs a large area for the groundwater discharge.

    While there are many types of sewer collection systems, two types are the most common, gravity sewers and low pressure sewers, both of which are detailed below:


      Gravity Sewer System — This type of system include a gravity sewer pipe coming from the house/building and flowing down the gravity pipe in the street to a treatment facility or intermediate pumping station. The Sewer Pumping Station pumps through a force main to another gravity sewer where the wastewater then continues to flow to a WWTF or another pumping station. The gravity connection at the house/building can be low enough to service the basement or lower level or might be considered “first floor service” only where often times homeowners might add an ejector toilet or sink in the basement.

      Gravity Sewer diagram: Public Sewer Main → Gravity Flow to Pump Station → Pump Station → Sewer Force Main (Pumped Uphill) → To Wastewater Treatment Plant
      Gravity Sewers

      Low Pressure Sewer System — Low pressure sewers typically consist of much smaller sewer pipes in the street that operate under pressure. Each home flows into a small grinder pump station which pumps into the force main. This system is typically located outside of the home/building and all that is visible is the access cover/hatch and a control panel located at the house possibly with an alarm light. This system requires power to operate, but usually has enough storage in the tank of the pump station to store about a day’s worth of flow.

      While this description is for the complete low pressure system, often times there is one low lying home that might require a low pressure connection to a gravity sewer system. This avoids the sewer from being extremely deep substantially increasing project costs. Homeowner connection costs (private property portion) are usually comparable to gravity sewer connections because the purchase price of the pumping package (~$5k) is offset with the cost of the deeper gravity sewer pipe.

      Low Pressure Sewer diagram: Gravity Sewer from House + Cleanout → Collection Tank (Storage) with Grinder Pump and Level Control Floats Operated by Control Panel → Service Box → Public Sewer
      Low Pressure Sewers