The short version
In a July 25, 2025 memo to the Falmouth Select Board, Wastewater Superintendent Amy Lowell updated how much treated wastewater the town's Main treatment plant can still release to the ground. She lowered the starting flow she uses for the town's "flow neutral" bylaw reviews, added up the flow already committed, including the next sewer area, Great Pond Phase 1, and found that 628,000 gallons a day (gpd), or 88% of the 710,000 gpd permit, is spoken for. That leaves 82,000 gpd for new development and bylaw variances until an ocean outfall, projected by 2032, adds capacity. She suggests the board weigh future requests with that limit in mind. This is a short town memo, and we read all of it, along with the one-page 2018 guidelines attached to it.
What the report covers
The memo is two pages from the Wastewater Division to the Select Board, copied to the Town Manager, Health Agent, Town Planner and Zoning Administrator, with a one-page attachment.
- Why the town's approach to discharge capacity has changed: new groundwater discharge sites, and even larger volumes at the existing one, are hard to permit.
- A revised starting (baseline) flow for reviewing flow neutral bylaw variance requests.
- The flow expected from projects already granted variances and from Great Pond Phase 1, added to existing flow and compared with the plant's permitted discharge.
- What the plant's discharge permit requires as flow grows, and what the town has told the state Department of Environmental Protection (DEP).
- An attachment: guidelines and priorities for variance requests that the Select Board adopted on June 4, 2018.
What it found
- Two commitments. The town has committed to using much of the remaining capacity under its existing groundwater discharge permit for Great Pond Phase 1, the next sewer area, and to working to permit an ocean outfall for all current and future treated wastewater (Lowell, 2025).
- A lower baseline: 489,000 gpd. Earlier variance reviews started from 535,000 gpd, an estimate built on historic flow and projected Little Pond flow. The highest actual yearly average at the Main plant in the past seven years, since Little Pond was connected, was 489,000 gpd, so Lowell will now use that figure.
- 88% already spoken for. Adding 25,000 gpd from projects with variances that weren't occupied in 2024 (such as Lyberty Green and the housing project at 763 Main Street) and 114,000 gpd from Great Pond Phase 1 once all connections are done, projected by the end of 2029, gives 628,000 gpd. That is 88% of the 710,000 gpd yearly average the plant is permitted to discharge.
- 82,000 gpd left. That is the remaining permitted capacity for growth from by-right development (building allowed without special permission) and from flow neutral variances, until more discharge capacity exists. Lowell projects the outfall will be available by 2032.
- A state trigger at 80%. The plant's permit requires the town to give DEP a plan once actual yearly flow reaches 80% of the permitted flow. The memo says the town has already told DEP about its Great Pond Phase 1 and outfall plans and will keep updating the agency through the outfall review and watershed permitting.
- A caution for the Select Board. Lowell suggests the board consider future variance requests with the limited capacity in mind. The attached 2018 guidelines call for Board of Health confirmation that a standard on-site (Title 5) septic system could serve the project, confirmation of plant capacity from the superintendent, and a public hearing. They list priority areas: economic development, affordable housing, mixed-use development in the business redevelopment zone, and municipal use.
What it means for Waquoit Bay today
This memo covers capacity and permits at Falmouth's Main treatment plant. Great Pond and Little Pond are separate south-coast estuaries outside the Waquoit Bay watershed. We summarize it because it shows how much room Falmouth has left to take in new sewer connections, and because Falmouth shares the Waquoit Bay watershed with Mashpee and Sandwich.
The outfall is the longer-term piece. CPWB covered the town's draft environmental report on it, which describes a pipe discharging to Nantucket Sound (see Falmouth sends its ocean outfall impact report to the state for review). Sewers are one tool among several in Falmouth; for a study of another one, see groundwater seeps in a restored Coonamessett bog, which found that restoration there removed well under 1% of the river's nitrogen. For the earlier sewer areas, see the USGS look at groundwater after Little Pond's sewers (Do sewers clean up the groundwater right away?) and the town's 2019 plan update (What is Falmouth's plan to cut nitrogen in its estuaries?).
Read the memo
Lowell, A. (2025, July 25). Flow neutral bylaw – Update regarding discharge capacity [Memorandum to the Select Board]. Town of Falmouth, Department of Public Works, Wastewater Division. https://www.falmouthma.gov/DocumentCenter/View/19869/Select-Board-Flow-Neutral-Bylaw—Update-Regarding-Discharge-Capacity-7-25-25
License: This is a Town of Falmouth public document with no open license stated, so we link to the town's copy rather than host the PDF. This summary is based on the full memo and its one-page attachment. The card image is the first page of the memo, shown as a card only.
Drafted with AI assistance from the linked source.
