Tipperary County Council has improved their water treatment detection systems.
It follows an incident in September 2017 when residents in the Cloughjordan area were exposed to E.coli in their drinking water.
A council official failed to notify Irish Water when the chlorine dosing pumps stopped working properly.
The council consulted with the HSE after the error was detected and decided it wasn’t necessary to notify householders when the resampling results proved the E.coli levels weren’t dangerous to humans.
Senior Engineer Denis Holland says the council has learned from the mistake.