The Nantucket Board of Health on Sept. 10 voted to extend for 60 days a moratorium on septic-system nitrogen‑loading credit variances in the island’s Wellhead Protection District and Hummock Pond area, and directed staff to prepare draft regulatory language for town‑counsel review and public notice.

The moratorium, first adopted in June, temporarily bars new variance approvals in the two protection zones while the board develops findings and a regulatory proposal. The board said the pause is intended to allow time to evaluate more recent testing and to align local rules with emerging state guidance on nitrogen‑reducing systems.

Board members and technical presenters discussed the scale of the risk to the island’s single‑source aquifer and considered whether rules already applied in Nantucket Harbor and Madaket Harbor should be extended to the other two districts. In discussion the board cited recent well testing and transfer‑of‑property data that staff supplied and asked for a written regulatory proposal to be circulated to town counsel and posted for public comment.

“For the record, Paul Santos with Nantucket Surveyors” said the special meeting was “posted as a follow‑up discussion on the septic system nitrogen loading credits in nitrogen and pathogen pathogenic sensitive areas, which specifically relates to the moratorium,” underscoring that the advertised purpose was to address the moratorium and its next steps.

Board members described the island’s single‑source aquifer as a primary public‑health concern and debated two near‑term options: (1) extend and apply existing Nantucket Harbor/Madaket Harbor rules to the Wellhead and Hummock Pond areas, or (2) take a staged approach that first extends existing rules and later moves to a stricter “best available technology” standard such as the 10 milligrams per liter total nitrogen target discussed by state regulators and some Cape towns. One board member summarized the risk by noting that “our primary mission is to protect the health of the citizens” tied to water‑supply protection.

Technical points presented in the meeting and reflected in board questions:
- The board said variances granted in recent years are concentrated in the two districts: the transcript record given to the board shows five variances in the (transcript term) Grama Pond Watershed and nine variances in the Wellhead Protection District since the board began compiling transfer/application data.
- Commonly installed nitrogen‑reducing alternative systems on the island (SeptiTech/MicroFAST in current use) are reported in the meeting to produce effluent around 19 milligrams per liter total nitrogen; some provisional or newer systems aim for approximately 10–11 mg/L and are on provisional lists with the state for broader approval.
- Board members and outside presenters noted legal and procedural limits: changes beyond Title 5 require written regulations, a posted public‑hearing schedule, and scientific findings to justify requirements that go beyond state code.

The board voted to extend the moratorium for 60 days and tasked staff and designated board members to draft regulatory language. The board directed staff to: produce a draft by about Oct. 15, send the draft to town counsel for review, and meet the newspaper‑notice schedule so the board could proceed with public notice and a hearing with the goal of taking final action at the board’s November meeting. One board member urged allowing a week or two for public comment after the draft is posted; another emphasized that a longer notice window may be needed for legal notice requirements.

The meeting also included discussion of implementation constraints: availability and local installation capacity for higher‑performing systems, cost differences between systems, and the risk that requiring provisional technology could create supply or affordability problems. Presenters recommended using language such as “best available nitrogen‑reducing technology” and flagged that any regulation should avoid steering applicants to a single product while leaving clear performance standards.

The board’s action was a procedural extension of the moratorium rather than an immediate change to permitting criteria. Members agreed on a path forward: extend the moratorium, prepare findings and draft regulation language that adapts existing harbor rules for the Wellhead and Hummock Pond areas as an initial step, and pursue further changes — including considering a 10 mg/L standard — after technical, legal and public review.

The meeting closed after the motion to extend the moratorium carried (voice vote recorded as “Aye”).