Man Fishing in the River
Wastewater Regulation and Why it Matters for Massachusetts Rivers

Wastewater from municipal and industrial sources has historically been one of the most serious threats to water quality, discharging bacteria, industrial waste products, pharmaceuticals, and many other waste products into our waters. These nutrients have contributed to excessive plant growth in our rivers, and depleted oxygen necessary to support aquatic species health. High levels of chemical buildup harm species living in or along rivers, while also affecting downstream communities that use rivers for drinking water. Unfortunately, many Massachusetts waterways still suffer from nutrient pollution from wastewater treatment plants, including the Assabet and Blackstone Rivers.

The Clean Water Act, passed in 1972, created the National Pollution Discharge Elimination System (NPDES) Program to address these ‘point’ sources of discharge.

In Massachusetts the NPDES program is responsible for successful efforts to restore and protect the Assabet River, which has four municipal wastewater treatment plant discharges along its course and very high levels of phosphorus in its water. To learn more about wastewater issues on the Assabet, go to

The health of the Charles River, the Nashua, the Blackstone, and Boston Harbor have also greatly improved, thanks to the NPDES program.


The Clean Water Act identifies various threats to our waterways and categorizes them as ‘point’ sources, which are from a specific location, and ‘nonpoint source’ which is pollution from a diffuse source. Regulatory programs are created in the Act to address each of type of pollution. The following link is a great outline of important parts of the Clean Water Act: The National Pollution Discharge Elimination System (NPDES) program addresses pollution from point sources, such as wastewater treatment plants. Under this program, permits are issued that specify the effluent limits for each pollutant in the wastewater. These limits are set based on water quality standards. (


Many states have ‘primacy’ from the federal government and administer their own NPDES program. Massachusetts does NOT do this, and EPA, in cooperation with the state, is responsible for issuing these permits. EPA also takes the lead on enforcement of these permits as well as any appeals that are filed. Massachusetts is still responsible for setting water quality standards and monitoring water quality. The state periodically evaluates the feasibility of taking on this program, but has consistently declined to do so, due to cost concerns. Massachusetts sets water quality standards based on designated uses of the water body, i.e. fishing, swimming, boating, etc. The state then determines water quality criteria required to meet these uses. Some criteria are numeric; for example, a water body can contain no more than a specified concentration of a specific pollutant; while other criteria are narrative and describe the qualities the water body should have, such as ‘free from excessive algae blooms’. These standards and criteria form the basis of permits, which protect water quality. This link provides an overview of water quality standards: The Clean Water Act requires states and EPA to protect water quality and not allow it to degrade from its current designated use. To do this Massachusetts sets antidegradation policies to ensure that water quality does not degrade over time. Follow this link to learn more about Massachusetts water quality standards and antidegradation policy: Additionally, you can view water quality data/reports from 2005-2014 on the state’s Department of Environmental Protection’s website ( Massachusetts is also responsible for completing planning efforts required by the Act, like total daily loads (TMDLs), to determine the resiliency of a river when accepting wastewater (or stormwater). Specifically, the TMDL determines how much of a pollutant a waterbody can receive and still meet water quality standards for that pollutant. Only waters that are classified as ‘impaired’, because they do not meet their water quality standards are required to have a TMDL. This link to EPA’s website provides an overview of the TMDL program: Phosphorus and bacteria are common causes for impairment of MA waters, and many TMDLs focus on these contaminants. This link is specific to Massachusetts and not only explains the program, but provides a status report on TMDLs required within the state: TMDLs require an intensive effort by the state to monitor, model and evaluate river impairments. Once completed, they provide a target for restoration, and ideally, a specific plan to reach these targets. Unfortunately, MassDEP’s resource constraints have prevented the agency from developing TMDLs at the speed that many advocates would prefer and which the CWA outlined. TMDLs are a powerful tool for Mass Rivers and its member organizations, and have helped to guide restoration efforts on many rivers. On the Charles River, a TMDL for the Upper Charles communities focused attention on excessive nutrients from combined sewer overflows and formed the basis for an aggressive monitoring and remediation program. By 2015, the river is virtually always safe for boating and considered swimmable 70% of the time, something that could not be imagined twenty years ago. Although not required by the CWA, Massachusetts issues permits for wastewater discharges over 10,000 gallons per day into groundwater. This helps maintain quantity of water in a watershed, and in many cases contaminants in the water are attenuated in the ground (as with a septic system). Proximity to surface water needs to be evaluated, though. The Eel River Watershed Association appealed a groundwater discharge permit in Plymouth because research showed that the nitrogen in the wastewater would lead to increased algal blooms in the river. The following link provides background information on the groundwater discharge permit program: Massachusetts does set standards for septic system disposal through Title 5 of the MA State Environmental Code. These regulations are implemented at the local level with oversight by the state. The following link provides general information about Title 5:


Local Boards of Health generally are responsible for implementing septic system regulations. When ownership is transferred through a home sale, the septic system must be inspected to determine if the system is in compliance with Title 5. At other times local boards of health respond to complaints and provide guidance to homeowners. There are a variety of guidance documents available for homeowners to help them understand and manage their septic systems so that water quality is protected. Here are a few examples: (1) (2) Septic systems are a great way to dispose of sanitary waste when they are operated properly. They return water to the ground, replenishing groundwater; and they disperse waste so that the nutrients from the waste can attenuate and bind with soils, thereby not reaching rivers and lakes. However, if they are not working properly, septic systems can be a source of contamination to ground or surface water.