Calls are being made for systems to be upgraded.
Westmeath County Council are having to refuse housing developments in certain towns and villages as the waste water systems are at capacity.
Fianna Fáil councillor Alfie Devine is calling for upgrades for sewage treatment plants across the county or for Uisce Eireann to take charge of proposed temporary mini plants.
Collinstown recently saw a housing development refused due to waste water capacity.
A proposed mini plant has been refused by the local authority on the basis Irish Water wouldn't maintain it.
Councillor Devine says this will present a huge problem going forward: