Concord Board of Health approves local upgrade for 43 White Ave septic system with nitrogen-reduction condition

The Concord Board of Health voted unanimously on March 19, 2025, to approve a local upgrade approval (LUA) for a failing septic system at 43 White Ave with the condition that the owner install a nitrogen-reduction system.

The parcel sits on White Pond and is described in the application as a very small, under-5,000-square-foot lot with the house located close to the water. Public Health Director Melanie reviewed White Pond’s recent history of cyanobacteria (blue-green algae) blooms, explained work already performed at the town beach and on private properties, and recommended a nitrogen-reduction condition for the septic repair given the pond’s sensitivity.

Nathaniel, an engineer working with the applicant’s consultant, presented a detailed plan for a repair using a pressure-dosed (presby) leach-field arrangement, a replaced septic tank, a pump chamber and a distribution box. He explained the topographic constraints: the lot slopes toward the pond, the available area is tightly constrained so the leach field must be set uphill from the tank, and several Title 5 waivers were needed. The team requested reductions from: the Town of Concord 75-foot waterway setback (they sought ~66 feet); property-line setbacks (a closest distance of about 5 feet where 10 feet is normally required); and an increase in maximum cover depth for a pump chamber (about a foot above the 36-inch standard, i.e., roughly 4 feet). The well on the property is approximately 64 feet from the proposed leach field (100 feet is preferred but generally impossible on the lot), and the septic tank would be more than 50 feet from the well.

The board discussed alternatives and nitrogen-removal technologies. Nathaniel said a commonly used in-tank nitrogen-reduction unit (a “FAST”/microFAST-style unit) could be installed and estimated the unit cost at about $6,000 plus roughly $1,200 delivery (about $7,000), with ongoing annual operation and maintenance costs. A complete new system of the size and complexity proposed was estimated to cost “tens of thousands” of dollars — Nathaniel and staff offered a rough all-in range of about $30,000 to $35,000. Melanie reminded the board the town offers an abatement loan program for failed systems that can provide up to $30,000 to eligible owners and is repaid over 10 years.

Board members asked whether the proposed nitrogen-reduction condition should be codified for all future repairs in the White Pond area; staff said DEP supports the concept but recommended putting it in the town’s local septic regulation before making it a standing requirement. The board approved the LUA with the condition that a nitrogen abatement system be incorporated; staff will inform the owner and prepare revised plans. Members also asked staff to explore amending local septic regulations and to consult with neighbors and conservation as part of any regulatory change.

The approval included formal sign-off by the board; there were no recorded dissents.