Mount Sunapee Wastewater Treatment Lagoons

Click here to read DNCR Commissioner Sarah Stewart’s letter to Mount Sunapee Resort’s General Manager Susan Donnelly regarding the 2025/2026 Annual Operating Plan.

Take Action to Protect the Lake Sunapee Watershed!

Mt. Sunapee Resort’s aging septic lagoons are putting Lake Sunapee and our local economy at risk. Please help us promote the common-sense solution of replacing this outdated system from 1972. The 50-year-old practice of spraying septic effluent directly into wetlands and forests upstream of Lake Sunapee’s State Beach should end. See a proposed solution here.

Over 200 people attended the Mount Sunapee Advisory Commisison Meeting on June 3,2025.

Here’s what you can do:

Read LSPA’s public comment letter regarding Mount Sunapee’s 2025 Annual Operating Plan (AOP) here.
Learn more about this issue in this presentation.
Alert others in our community about the issue (spread this message widely).
Watch the full recording of the June 3, 2025 MSAC meeting provided by YCN
Read recent articles about this issue from
1. Environmental Groups, State Regulators at Odds on Mount Sunapee Septic System - Clare Shanahan, Valley News
2. Advocates Say Ski Resort’s Wastewater May Contaminate Lake Sunapee. State Regulators Disagree. - Julia Vaz and Mara Hoplamazian, NHPR
3. Groups Seek New Wastewater Treatment System at Mt. Sunapee Resort - Clare Shanahan, Valley News

Our Next Steps

Following the June 3rd Mount Sunapee Advisory Commission Meeting, we requested collaborative stakeholder meetings with DNCR, DES, and Mount Sunapee Resort to discuss solutions to this issue within 30 days.
We are partnering with the Newbury Conservation Commission to collect additional water quality data downstream from the septic effluent lagoons.

Collaborative Actions

We hosted a stakeholder meeting of conservation leaders at LSPA's Center for Lake Studies on Tuesday, May 6, 2025, to discuss concerns about the wastewater treatment system at the Mt. Sunapee Resort and to devise strategies for the Mount Sunapee Advisory Commission meeting.
We worked with the Newbury Conservation Commission to compile and analyze historical documents and data about this issue which dates back to the 1970s. This research is summarized here.
The Newbury Conservation Commission held a general informational meeting on Monday, May 19, 2025, at the Newbury Town Offices to present data and solutions to inform the public about the issue. The meeting presentation can be found here.
LSPA requested action to replace the dated system at the Mount Sunapee Advisory Commission, which was held on Tuesday, June 3, 2025, at 10 AM at the Sunapee Lodge at the Mount Sunapee Resort.
Over 200 people attended the Mount Sunapee Advisory Commission, including a strong turnout from LSPA members and partners.

June 2025 - LSPA’s Response to Mount Sunapee’s Annual Operating Plan

The Mount Sunapee Advisory Commission (MASC) held a meeting on June 3, 2025 to discuss the Mount Sunapee Annual Operating Plan (AOP). LSPA’s Executive Director, Elizabeth Harper, sits on the MASC and provided this public comment letter.

April 2025 - Concerns Remain About the Mount Sunapee Wastewater Treatment Lagoons

LSPA and The Newbury Conservation Commission (NCC) remain extremely concerned about the water quality impacts of the outdated and poorly functioning wastewater treatment system in use at the Mount Sunapee Resort since 1972. The system stores effluent from septic tanks in a series of unlined lagoons. It uses a spray irrigation system to spray effluent into three vegetated fields, but some of the spray goes into natural wetlands. Because the lagoons are unlined, they leak an unknown amount of effluent into groundwater and into Beck Brook, which flows into Lake Sunapee at the State Beach. It is the oldest version of this type of system currently in use in New Hampshire, and several similar facilities in the state have been denied Department of Environmental Services (DES) permits. Yet a Groundwater Discharge Permit has been granted for Mt. Sunapee Resort’s facility despite the fact that it has regularly exceeded the required water quality standards in the permit for Total Suspended Solids (TSS) on over 48 occasions (62% of samples from 2018 – 2024) and has exceeded the Biological Oxygen Demand (BOD) standard at least 15 times (approximately 20% of samples from 2018 – 2024). Data from these monitoring well reports are publicly available on DES’s OneStop system.

June 2024 - LSPA’s Response to Mount Sunapee’s Annual Operating Plan

The Mount Sunapee Advisory Commission held a meeting on June 11, 2024 to discuss the Mount Sunapee Annual Operating Plan (AOP) which details a parking lot expansion at the Mount Sunapee Resort (Draft Minutes from the June 11, 2024 MSAC meeting). Executive Director, Elizabeth Harper, sits on the Mount Sunapee Advisory Commission and was able to not only attend the meeting in June, but also to provide a position statement. The position statement included the concerns raised by LSPA and other local stakeholders including the Newbury Conservation Commission and the Friends of Mount Sunapee. In the statement Elizabeth Harper recommended that the parking lot expansion should be placed on hold until the following occur:

The integrity of the dam has been thoroughly evaluated by a qualified engineer.
Extensive water quality sampling has been conducted on the seepage from the dam.
An end-of-life plan is in place for the existing outdated wastewater treatment system.
A comprehensive stormwater management plan is in place for the area under lease.
Public hearings are held to allow for input from the community.