Pollutants and pollution in bathing waters

Pollution has a specific meaning under the Bathing Water Regulations 2013 (SI No. 1675). 

For these purposes, the term ‘pollution’ refers to:

  • faecal bacterial pollutants (enterococci, streptococcus or coliform)
  • certain types of algae (cyanobacteria or macro-algae)
  • physical pollutants which might pose an acute risk to the health and safety of bathers (wastes, tars)

Bacterial pollution is pollution where it represents an acute or unacceptable risk to the health of bathers. The regulations do not specify a concentration that amounts to pollution.  

The water quality classification standards given in the regulation are not designed to serve as concentration limits that can be compared to an individual sample result, concentrations exceeding the standards are permitted, provided that they don’t occur more frequently than the regulations allow.

Because of the amount of time it take to analyse an environmental sample, it is not possible to proactively monitor water quality and to have results quickly enough to take action to prevent bathers becoming exposed to pollution.

Unacceptable bacterial pollution can be assumed where significant amounts of sewage are observed either in water or on the bathing water foreshore.

Duty to manage pollution

Regulation 12 (SI No. 2013/1675) describes the duties of the Environment Agency, Southern Water and Havant Borough Council, where pollution is identified. 

These duties only apply at bathing waters, and only where there is likely to be an unacceptable risk to bathers.

Risks to other water users, from other forms of pollution, at locations not designated bathing beaches, or to the wider environment or ecology are not covered by the provisions of the bathing water regulations.

The council will respond to reports of significant pollution of a type not covered by the bathing water regulations in line with it’s general emergency-planning procedures.

Abnormal situations (pollution)

As bathing water classification represents water quality over the previous four bathing seasons, the standard achieved could be adversely affected for several years by a single pollution incident.  To avoid this, the regulations allow for the Environment Agency to decide that a single pollution event, or combination of events amount to an abnormal situation. 

Scheduled sampling may be suspended during an abnormal situation and any samples taken may be disregarded for classification purposes.

Strict conditions apply to the exercise of these provisions, and sufficient catch-up sampling must be undertaken following the event to ensure that a water quality classification can be properly calculated for the next season. 

Identifying pollution

Contamination which affects bathing water quality or which presents a risk to bathers' health and safety might amount to ‘pollution’ for the purposes of the Bathing Water Regulations 2013 (SI No. 1675).


The presence of identifiable sewage in bathing waters indicates that bathers health is likely to be at risk from intestinal enterococci or escherichia coli and is pollution.

Seaweed (Macro-Algae)

Where seaweed is present in such quantity as to risk entangling swimmers, it is pollution.

Blue-green Algae (Cyanobacteria)

Cyanobacteria cannot be seen unless conditions allow populations to bloom, where the bacteria can clump together and colour the water.

This can look like foam, scum, or mats - particularly when the wind blows them toward a shoreline.

Despite the common-name, blooms can appear blue, bright green, brown, or red, and sometimes look like paint floating on the water’s surface. A bloom may form a foam when agitated by surf or whipped by wind.

Cyanobacteria are not readily distinguished by the naked eye from other forms of phytoplankton, so any suspicious bloom should be treated as possible pollution.

Blooms do not commonly occur at Hayling’s bathing waters, but any suspected occurrence should be reported as a precaution.

Other pollution

Accumulations of waste materials that might cause disease or injury are also considered pollution for the purpose of bathing waters regulations. This includes tars, oily residues, glass, plastics or rubber. 

Any wastes on the beach or in the water which may cause injury, illness, or which risk entangling bathers should be reported.