Charles River swimmers will have to wait a week before they can dunk

The Charles River Conservancy hosted the first public swim in the Charles River in 50 years in July 2013.John Tlumacki/Globe Staff/File/Globe Staff

Those looking to hop into the Charles River on Saturday for the “City Splash” event will have to wait another week to jump in.

The noontime event — at which the state grants special permission for swimmers to dunk near the Fiedler Community Dock on the Esplanade — has been moved to Saturday, June 22, according to an e-mail sent to participants Friday. It’s combined this year with the Charles River Swimming Club’s annual 1-mile swim at 8 a.m., which was also rescheduled.

The event was postponed because of Thursday’s heavy rainfall, which introduced additional pollutants into the Charles River, exceeding the maximum amount allowed under regulations, Laura Jasinski, executive director of the Charles River Conservancy, which hosts City Splash, said in a statement.

The rise in pollutants is temporary, and the water will be retested next week to ensure it’s safe for the swim that Saturday, the Charles River Conservancy said.

All tickets will be honored for the rescheduled event, and the organization said it will do its best to accommodate participants’ time slot changes for City Splash.

About 200 people are planning to swim the mile, while about 300 have registered to jump in off the docks, Jasinski told the Globe on Thursday. (City Splash is already sold out, and those who registered to hop in had to pay $10 to make sure they’d commit to showing up.)

The event also promises to expand even more than recent years. In addition to the swimming events, there will also be activities on dry land from noon to 4 p.m., including a food truck, a frozen treat cart, games, face painting, and tote bag decorating, to name a few.

“We want to be more of a festival, a community event, so if you want to check it out and not get wet, there are things to do,” Jasinski said, noting that those activities will be free and open to the public.

Participants concerned about the water quality of the river following the river’s recent EPA grade drop from an A- to a B last year need not worry, Jasinski said.

“The EPA water grade is an indicator of the year overall, an average of a year,” Jasinski said. “But we test to make sure it’s safe [in real time], too.”