The Southborough Conservation Commission continued a public hearing for replacement of a failed septic system at 3 Bridge Street after staff and peer review raised questions about wetland flags, riverfront-area work and floodplain impacts.

David Schofield, the applicant’s representative, said the existing system is old and failing and that the proposed replacement is an elevated Presby system intended to reduce the leaching-field footprint and to maintain a gravity flow arrangement. “This site is on the corner of the lot... it abuts the Sudbury River,” Schofield said, and he described test-hole results showing shallow groundwater (approximately 28 inches) that require an elevated system. He said the proposed system’s footprint is roughly 60% of a traditional septic area and includes an impermeable barrier and erosion-control silt fencing to reduce grading.

Joe (peer reviewer) told the commission he visited the site and said several wetland flags appeared to be placed low relative to field indicators; he estimated some flags were 4–11 feet low and requested verification of the mean high-water line flags. He also noted the property lies in the 100-year floodplain and that the proposed leaching field may be partially within bordering land subject to flooding; because the proposal raises ground elevation, Joe recommended the applicant address compensatory flood storage. Joe also requested a certified abutters list, completion of wetland evaluation forms and a confirming DEP file number; at the meeting no DEP number had been issued.

Schofield said the existing system appears to have been installed decades ago and is likely pre-1996; if the original installation predates Aug. 7, 1996, the proposed work may qualify for certain exemptions from riverfront-area standards, but the applicant must confirm that installation date in the application. The commission also noted the applicant will likely need to provide an alternatives analysis and a waiver request if riverfront-area work is not exempted.

Commission staff and members agreed to continue the hearing to allow the applicant to supply missing documents, provide clarifications on the wetland delineation, confirm whether the existing system predates 1996 and to consider compensatory flood storage calculations.

No permit decision was made at this meeting; the hearing was continued for further review.