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Monitoring and analysis

Sampling programme

Water quality samples are taken at each bathing water throughout the bathing season, from 1 June to 15 September. A pre-season sample is taken during the last fortnight in May.

The dates we take samples on are set in advance of the bathing season. We sample on these dates unless there is an unexpected operational reason e.g. vehicle breakdown.

Most bathing waters are sampled 18 times during the season. Some geographically remote sites are sampled 10 times. Sites which have consistently demonstrated excellent water quality are sampled five times.

Additional investigative work is undertaken as needed to identify pollution sources which may affect our bathing waters.


We analyse water samples for Escherichia coli and intestinal enterococci and post the results throughout the bathing season. We make observations at bathing waters for cyanobacterial (blue-green algae) blooms, macroalgae (seaweed), marine phytoplankton and other waste and instigate actions if required.

Bathing water quality classifications are calculated at the end of the season and apply to each bathing water for the duration of the following season.

All of our sampling is in accordance with Bathing Water Directive (2006/7/EC) which came into force on 24 March 2006 and was translated into Scottish law by The Bathing Waters (Scotland) Regulations 2008.

Short term pollution

Our electronic signage network at selected sites across Scotland provides real-time predictions of bathing water quality. This allows potential bathers to make an informed choice about using the water.

Any samples collected during short-term pollution events, when there is a public warning system in place to inform prospective bathers of potentially poorer water quality can be removed from the overall classification dataset. Management measures must be in place to prevent, reduce or eliminate the causes of the pollution. A maximum of 15% of samples can be disregarded from the classification dataset and, if necessary, replaced.

Abnormal situations

An abnormal situation is defined by the Bathing Waters (Scotland) Regulations as an event or combination of events impacting upon bathing water quality which SEPA would not expected to occur, on average, more than once every four years. During an abnormal situation signs must be in place warning the public of the nature and expected duration of the pollution. The monitoring calendar can be suspended so that samples which assess compliance of the bathing water are not taken as they are unrepresentative of the usual water quality. 

Bacteriological analysis

Bacteriological analysis is carried out at our specialist microbiological laboratories in North Lanarkshire and Aberdeen. All of these laboratories operate to United Kingdom Accreditation Service quality systems for their analytical work. We also participate in external inter-laboratory testing schemes such as those run by the Public Health Laboratory and Aquacheck. The inter-laboratory testing has demonstrated consistent high accuracy of our bacteriological test results.