Concord emergency crews responded to several incidents at Walden Pond during July's heat wave, prompting town officials to remind swimmers: stay within the roped area where lifeguards can reach you.

Under DCR rules, swimming outside the roped-and-buoyed area is not allowed from 10 a.m. to 6 p.m. while lifeguards are on duty. Open-water swimming is permitted only before 10 a.m. and after 6 p.m., and swimmers must carry a brightly colored swim buoy attached by a strap. The rules have been in effect since at least 2022.

Town Manager Kerry Lafleur raised the safety concern during her July 6 update to the Concord Select Board. She said the pond has seen a small uptick in activity during the stretch of hot weather and noted that while lifeguards are stationed within the roped swimming area, many visitors choose to swim beyond it. Lafleur did not detail the nature of the incidents.

"I would just remind people to know your limits," Lafleur told the board.

Walden Pond State Reservation draws heavy weekend crowds from Lexington, Concord, and surrounding towns. The pond is more than 100 feet deep in places and a half-mile long, according to the Massachusetts Department of Conservation and Recreation.

A DCR spokesperson said water rescues at the pond remain uncommon overall and that staff respond to very few water emergencies each year, including this summer. Lifeguards remain available to assist swimmers within guarded areas, the spokesperson said.

Concord Police Capt. Brian Goldman told The Concord Bridge that local officers have limited involvement at Walden during the summer because DCR oversees the reservation. Goldman said most police calls to the pond have been parking-related.

The pond saw heavy use over the July 4 holiday weekend, with multiple capacity closures and reopenings on Saturday, July 4, and Sunday, July 5.

If you go

• Where: Walden Pond State Reservation, 915 Walden St., Concord
• Hours: 5 a.m. to 7:30 p.m. daily
• Parking: $8 for Massachusetts plates, $30 for out-of-state vehicles
• Closure alerts: mass.gov/parkalerts or (978) 369-3254