SOUTH PORTLAND — City officials are considering zoning changes intended to streamline and clarify regulations related to nonconforming residential lots.

The Planning Board has invited 6,200 property owners in Residential A and AA zoning districts to a public hearing on the proposed changes that will be held Nov. 15 starting at 7 p.m. in the lecture hall at South Portland High School. Bright-yellow postcard invitations were mailed last week.

Triggered by a recent lawsuit, the proposed changes pertain to the construction of single-family homes on existing legal nonconforming lots and the required minimum house lot sizes in residential districts. More than 20 requests to build houses on nonconforming lots have been put on hold pending the City Council’s decision on the proposed changes.

The changes would preserve the right to build on nonconforming lots under more restrictive standards, said Tex Haeuser, the city’s planning director.

As a result, all proposals to build new homes on existing legal nonconforming lots would require a public hearing and review by the Planning Board; currently, only homes on lots under 5,000 square feet require the board’s review.

The proposed changes also would reduce the minimum buildable house lot size in many older neighborhoods, where 1960s suburban standards have proved to be too large and limiting, Haeuser said.

Under current zoning, the minimum lot size in a Residential A zone is one-quarter acre or about 12,500 square feet, and in a Residential AA zone it is one-half acre or about 20,000 square feet. New minimum lot sizes would be based on the median lot size of existing homes in each neighborhood as determined by GPS measurements, Haeuser said.

Minimum lot sizes would be as follows in various neighborhoods: Willard and Pleasantdale, 6,000 square feet; Ligonia, 6,500; Stanwood Park, Sunset Park and Thornton Heights, 7,000; Knightville, 7,500; Cash Corner and part of Ocean Street, 8,000; Loveitt’s Field and Meadowbrook, 8,500; Country Gardens and part of Highland Avenue, 12,500; part of Ocean Street, 13,500; part of Highland Avenue and Stanwood Park, 20,000.

The proposed minimum lot size for Meetinghouse Hill is undecided at either 6,000 or 7,500, Haeuser said.

After next week’s public hearing, the Planning Board will vote on a recommendation to the City Council. The council will then hold a workshop and two public hearings before taking a final vote on the proposed changes.

For more information about nonconforming lots, see the proposals posted on the Planning Department page on the city’s website, southportland.org, or contact Haeuser at 767-7648 or chaeuser@southportland.org.