The Rolfe Park pool closed Thursday after an unknown person jumped the fence and defecated in the water.
Concord Parks & Recreation Director David Gill said the vandalism happened Wednesday night. There are no suspects at this time.
Gill said the pool is closed while city staff “shocks” the pool water, a process where the liquid undergoes an intense chlorine treatment to get rid of any bacteria.
He said the city usually deals with similar incidents a few times a year and asked residents to please report any suspicious activity they hear or see at the pools after hours.
Gill anticipates the pool will be open Friday, weather permitting.
The city’s seven pools have been open since June 16 and will be open until Aug. 9.