Bathing waters at beaches are sampled and tested by the Environment Agency.
Bathing water is measured by the amount of bacteria within a water sample. Counts are undertaken throughout the bathing season to see if the water quality meets the European Union's (EC) Bathing Water Directive. The directive sets limits for a number of substances and all countries in the EU have to make sure their popular beaches meet these standards. These popular beaches are known as designated bathing waters.
Bathing waters must be tested at weekly intervals between 1 May and 30 September, with a minimum of 20 samples tested. There are two measurement criteria - a minimum standard, which must be met in order for a bathing area to pass and a higher standard, which member states should strive to achieve.