The group Surfers Against Sewage said their app can send alerts or text messages about discharges of sewage and storm water at almost 250 beaches in England and Wales.
The app, funded by Britain's Environment Agency, was created in response to concerns about a rise in sewage spills that represent a health risk to those enjoying the country's beaches, the BBC reported.
It creates alerts based on information from water companies on combined sewer overflows, when untreated sewage and storm water is released into the sea during periods of heavy rain to keep sewers from clogging and backing up.
In tests at three beaches in Cornwall, 94 percent of people who received alerts about short-term spills said they decided to take action to avoid them.
"This truly is an innovative concept, achieved thanks to years of campaigning against secretive combine sewer overflow sewage discharges from water companies," Surfers Against Sewage campaign director Andy Cummins said of the app.
The Sewage Alert Service app is available for download for both iPhones and Android phones.