Protesters are heading to Dollymount Beach in Dublin today to air their anger over bathing bans across the city.
The Love Dublin Bay Group want the constant overflows of sewage into the bay to be addressed.
The protest is set to begin at 8pm this evening.
Lab results from water samples taken on Monday are expected this afternoon, and if they come back clear, a "midnight swim" is planned.
John O'Donohue from Irish Water explains how and why the overflows occur, saying: "We had yellow rainfall warnings which means you can get anything up to two inches of rainfall during a 24-hour period so what happens then is the water combines with the sewer system.
"It overflows because the systems simply can't cope, so the system acts as a release valve... both on the network and at the waste treatment plants in order to allow the plants to function properly."
