People in North Tipp planing a trip to Lough Derg are being advised to exercise caution following the discovery of Algae Bloom in the water.
The bloom which forms a bright pea-green paint like scum on or close to the shoreline was discovered in the Youghal area in recent days.
Tipperary County Council says it can produce harmful toxins and that contact with the bloom should be avoided as it may cause skin irritation.
The authority is also warning pet owners to keep dogs away from the affected areas and to ensure they have an alternative source of drinking water.
Tipperary County Council may be contacted at 0761 06 5000.
