Conn. (WTNH) — The swimming area at Hop Brook Lake in Middlebury is closed until further notice, the U.S. Army Corps of Engineers, New England District announced Thursday, due to bacteria levels in the water.

USACE officials said water quality testing indicated the bacteria levels in the lake exceed state standards.

The swimming area will stay closed through the Fourth of July and until the next scheduled testing period next week. Officials said it will re-open when water quality test results are satisfactory.

Other recreational activities and facilities at Hop Brook Lake will remain open.

Squantz Pond in New Fairfield, Thompson’s Quaddick Park, and Gay City Park in Hebron all closed their swimming areas on Wednesday due to the presence of bacteria, DEEP said. The parks were retested, and on Thursday morning, Squantz Pond and Quaddick Park reopened, but Gay City Park remained closed. As of Friday, all three were open again.

In addition to the closures, the swimming area at Mashamoquet is closed for the 2022 season due to ongoing maintenance.

Samples are collected weekly by DEEP staff and are analyzed at the Department of Public Health for the presence of bacteria. While indicator bacteria are not disease-causing pathogens, they are one of the tools used by public health and environmental protection authorities to evaluate the potential for contamination of waterbodies, DEEP said.

All shoreline state parks are open.