An aerial view of the Lake Auburn Pump Station off Turner Street in Auburn. Russ Dillingham/Sun Journal file photo

AUBURN — The City Council will conduct a first reading on updated septic standards for the Lake Auburn watershed Monday, but a second reading will be delayed to allow the Planning Board to consider a simultaneous zoning change in response to development concerns.

Earlier this month, the council signaled its support for the septic design updates, which would allow property owners to utilize alternative soils in designing septic systems — something that has not been allowed in the watershed, but has also restricted development.

The issue has been part of a larger debate in Auburn and Lewiston regarding changes in the watershed and how to best handle water quality issues. While officials and city staff have said the updated standards will result in better performing septic systems, some have argued that the changes should be tied to development restrictions.

Many have pointed to a recent lake study, which included modeling that predicted roughly 100 homes being built under certain scenarios. However, city staff said Friday that the city has again hired consultant FB Environmental to conduct new modeling based on the proposed changes, which include new phosphorus control standards and a proposed shift to a three-acre lot minimum.

Eric Cousens, director of Planning and Permitting, said the city is “trying to capture the environmental benefit” of changing to better performing septic systems and other recommendations from the report, but without increasing density.

He said the city does not yet have an estimate of the number of homes that could be built under the new rules, but said the council will see some estimates Monday. He said staff is recommending the council delay a second reading until June to give FB Environmental time to conduct the new modeling.

Officials expect the number to be considerably less than the initial estimate of 100.

Recommendations from the Planning Board regarding the septic changes also included expanded water quality monitoring, and according to a council memo, “appropriate action if the monitoring process finds the water quality degraded because of development.”

The proposal also calls for requirements that all existing septic systems are inspected at the point of sale and continuously at five-year intervals. But according to Mayor Jason Levesque, an amendment may be introduced that would require existing systems to be replaced under the new standard at the point of sale.

According to the memo, the council will vote on a resolution Monday to forward the three-acre lot minimum proposal to the Planning Board.

“Staff applauds the Planning Board edits as a positive improvement for the strengthening of watershed protections,” the memo states.

John Blais, deputy director of Planning and Permitting, said in the memo that FB Environmental will draft a detailed description of how the proposed ordinance revisions will be incorporated into the new modeling, and “will perform the new model run and summarize the methodology and results in a brief memorandum to the city of Auburn for a future reading of the proposed changes.”

Auburn’s effort to update septic standards, as well as recent rezoning, led to a swift response from Lewiston, where officials have pressured Auburn to reconsider policy changes that would impact water quality.

Water officials in Auburn said this week they are consulting with legal counsel following “demand letters” from Lewiston requesting a moratorium on any new development in the watershed. The Lewiston Auburn Watershed Protection Commission board has called a special meeting Monday afternoon to “discuss our responsibilities and authority with regard to Lewiston’s Letter of Demand dated March 31, 2022.”