Bathing Waters and Blue-Green Algae

Identified and candidate Bathing Waters

Identified and candidate bathing waters are monitored by DAERA under the Bathing Waters Regulations throughout the bathing season (1 June – 15 September), with each site assessed 20 times during this period. This includes water sampling for faecal indicator bacteria and visual assessment of other potential pollutants.

Where there are concerns of risks to bathers’ health from a visual assessment showing blue-green algae, DAERA contacts the Bathing Water Operator to issue precautionary messaging to site users and encourage vigilance. Further assessment is made by taking water samples to establish levels in relation to agreed health guidelines for safe bathing. In the case of blue-green algae, the World Health Organisation (WHO)’s guidelines are applied.

The results of water sampling for blue-green algae are shared with the Bathing Water Operator, highlighting urgent action such as closing the site to bathing if levels exceed the safe threshold from WHO. Depending on the results, further water samples will be taken as required to better inform management of the site.

For more information please visit the About bathing water quality page.