Rossnowlagh is classified as achieving Excellent Water Quality in 2025 based on the assessment of bacteriological results for the period 2022 to 2025. Rossnowlagh has 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.

Rossnowlagh is west facing consisting of a long sandy beach confined by the Coolmore cliffs to the South and extends up to Inishfad at Durnesh Lake to the North. Rossnowlagh Beach is in the Donegal Bay SPA and is a very large, marine-dominated, site. There is a wide and diverse variety of wildlife including birds and seals. Activities at Rossnowlagh beach include swimming, kayaking, boating, windsurfing, sailing, surfing, power boating, jet skiing, diving and other land based activities on the beach. The designated bathing area is approx. 0.9054km2 and the extent along the water is approximately is 2150m. There is a medium sloping gradient off Rossnowlagh Beach with the water depth reaching 1m approx. 20m from the water line.