NEWBURY, N.H. — Conservation groups are urging the state to require Mount Sunapee Resort to replace an aging septic system as a condition of opening for the 2025-26 recreation season.

Vail Resorts, headquartered in Colorado, operates Mount Sunapee under a lease agreement with the state of New Hampshire. As part of the agreement, the state Division of Natural and Cultural Resources, or DNCR, must approve Mount Sunapee’s annual operating plan that covers types of recreational opportunities to be offered, days of operation and environmental matters. 

The 2025-26 Annual Operating Plan and the wastewater treatment facility will be discussed at the annual meeting of the Mount Sunapee Advisory Commission, or MSAC, on Tuesday. The commission is comprised of state and local leaders who advise the DNCR commissioner on the lease.

A coalition of local groups, including the Lake Sunapee Protective Association, which holds a seat on the MSAC, the Newbury Conservation Commission and the selectboards from towns around Lake Sunapee are pushing for Vail Resorts to replace the mountain’s 50-year-old wastewater treatment system. The groups are “advising” the commissioner to require it as a condition of the state approving the annual operating plan, according to a news release from the Lake Sunapee Protective Association released last week.

Constructed in 1970, the current wastewater system relies on evaporation from three unlined sewage “lagoons” and saturating adjacent fields with treated liquefied waste during non-winter months. The environmental groups have been raising the alarm about the system for more than a year.

The groups are “calling for the replacement of the outdated lagoon system with a package wastewater treatment facility,” according to the release. “...This solution is feasible, affordable, and long overdue.”

The group estimates a replacement system to cost approximately $1.5 million.

In response to questions about the request and the feasibility of building a new septic system, Abigail Allen, communications manager for Vail Resorts New Hampshire, said in a Friday email that “in partnership” with the state and local government “we diligently assess maintenance needs and update the existing wastewater infrastructure. This unified approach underscores our commitment to the environment while ensuring the  success of the resort.”

The Lake Sunapee Protective Association has asserted that some of the spray from the septic system goes into natural wetlands and the unlined lagoons “leak an unknown amount of effluent” into Beck Brook, which then flows into the lake at the state beach.

Along with its role in the region’s recreational economy, the lake also is the source of drinking for the town of Sunapee.

The state, meanwhile, has refuted the group’s concerns that there is any concern of contamination in Lake Sunapee from the septic system. 

“NHDES does not agree with claims that the facility is spraying directly into wetlands and surface water,” according to a March letter from Department of Environmental Services Commissioner Robert Scott to DNCR Commissioner Sarah Stewart.

The agency also argues that water quality testing has not “provided evidence of surface water impacts.”

Still, the Lake Sunapee Protective Association and other groups assert that there is evidence of contamination and that NHDES’ water quality monitoring is insufficient.

The group compiled historic data that indicate past issues with the septic system including its capacity, instances of contamination and recommendations from DES having not been met. Advocates are also awaiting results of their own water quality monitoring data.

Exacerbating concerns with the septic system are Mount Sunapee’s ongoing plans to build a new parking lot, which environmental groups argue would remove much of soil that filters the septic system effluent before it flows into the lake. 

The parking lot project has received several permits from the state to move forward and was scheduled to begin this spring, a spokesperson told the Valley News in November. But, the project has not begun and is not included in the 2025-26 operating plan. 

“The project is not delayed. We are constantly assessing timelines of all investments in improvements and have simply chosen not to include this in the current (annual operating plan) cycle,” Vail Resorts’ Allen said.

At Tuesday’s 10 a.m. meeting, the environmental groups plan to present their position on the issue, though it is not clear how much time they will have to do so, Dave Rhodes, a member of the Newbury Conservation Commission, said. 

In anticipation of a large turnout the meeting was relocated from the Newbury Public Offices to Mount Sunapee’s main lodge at 1398 N.H. Route 103 in Newbury. Remote participation or viewing will not be available.

Mount Sunapee’s proposed annual operating plan is available online at nhstateparks.org/about-nh-parks/park-administration-legislation/commissions-and-committees/mount-sunapee-advisory-commission.

Public comments on the plan can be submitted via mail to: Mount Sunapee Comments, Department of Natural and Cultural Resources, 172 Pembroke Road Concord, NH 03301 or emailed to MountSunapeeComments@dncr.nh.gov until 4 p.m. on Tuesday, June 10.

 Clare Shanahan can be reached at cshanahan@vnews.com.