Carrowniskey, Louisburgh is classified as achieving Excellent Water Quality in 2025 based on the assessment of bacteriological results for the period 2022 to 2025. Carrowniskey, Louisburgh achieved an Excellent Water Quality rating for the four consecutive years 2022 to 2025. Annual water quality ratings are generally calculated using monitoring results over a four-year period and are assessed against stringent bacterial limits to protect bather health.

Carrowniskey Beach is a large sandy, gradually sloping beach open to the west. Carrowniskey Beach is an exposed beach and can be subject to rip tides/strong currents. There are a number of different habitats including sand hills and an area of machair, three lagoon type lakes and their associated riverine channels. The Lagoon habitat is of extreme ecological importance. Carrowniskey Beach forms part of the Lough Cahasy, Lough Baun and Roonah Lough Special Area of Conservation (cSAC) and proposed National Heritage Area (pNHA) (Site Code 001529). The bathing water is approximately 0.8km2 in area however the beach extends approximately 1.7km. The medium and maximum water depth within the designated bathing water is 0.5m and 5.0m respectively depending on tides.