How clean is the sea?

You can avoid catching a nasty bug from swimming in polluted seawater this summer by finding out about the water quality at your favourite beaches.

“Pick a Blue Flag beach or an MCS-recommended beach.” Thomas Bell, coastal pollution officer at the Marine Conservation Society

Swimming in the sea and taking part in water sports such as surfing is invigorating and fun. But there are some health risks associated with swimming in polluted waters.

What are the health risks in seawater?

Most water-borne disease is related to faecal contamination from either humans or animals.

The main ailments caused by bathing in faecally contaminated water are gastrointestinal (digestive tract), such as dysentry, respiratory infections, and ear, nose and throat complaints.

Why are coastal waters affected by faecal contamination?

"Direct sewage discharge, sewage from stormwater overflows and sewage running off from streets and farmland (often through streams and rivers) can all affect the quality of coastal water," says Thomas Bell, coastal pollution officer for the Marine Conservation Society (MCS).

The degree of pollution from these sources varies from beach to beach, depending on the proximity of any sewage discharge and the type of sewage treatment that is used locally.

Weather also affects pollution.

"The quality of bathing water will drop 24 to 48 hours after heavy rainfall," says Andy Cummins, campaign manager for Surfers Against Sewage.

This is because combined sewage overflows (CSOs), which divert excess sewage from treatment plants into rivers and the sea to prevent flooding, are operated more frequently during storms. There is also a greater risk that the sea will be affected by polluted water draining from farmland after heavy rain.

Who monitors the quality of bathing water?

The UK, in line with other European Union members, is required to identify popular bathing beaches and test the water for faecal contamination during the summer season.

The test results are reported as follows: 

  • "poor" or "fail", which means the water has not met the minimum standards
  • "pass" or "good", which means it has met the minimum standards 
  • "excellent", which means the water has passed the higher guideline standards set by the EU

In 2010, 587 coastal bathing spots in the UK were monitored. Nearly all of these beaches (571) met the minimum standards (pass or good) and 421 of them also met the higher guideline standards (excellent).

To view a list of the beaches that were tested and the results of those tests, see DEFRA (for England and Wales), SEPA (for Scotland) and NIEA (for Northern Ireland).

The results of the previous summer’s environment agency tests (see above) are also used by the Blue Flag and MCS award schemes to recommend beaches.

How to avoid polluted water

"To minimise the risks of swimming in polluted water, pick a Blue Flag beach or an MCS-recommended beach," says Bell. "If it’s been raining heavily, stay out of the water for at least 24 hours."

According to Bell, if a beach meets the minimum EU mandatory standards or is rated as good, you still have a 12%-15% chance of contracting a sewage-related illness. At a beach that has met the higher EU guideline standards, this drops to 4%-5%.

Both the Blue Flag and the MCS award schemes (more details below) only include beaches that have met the higher EU standards (or in the case of the MCS recommendations, stricter criteria).

Beaches recommended by the Marine Conservation Society

The Good Beach Guide is published by the Marine Conservation Society (MCS) and indicates which UK beaches have excellent water quality.

By clicking on the guide's interactive map, you can find out about more than 1,000 beaches in the UK and Ireland. You can find out about the quality of bathing water, if the beach has lifeguards and if there are facilities such as toilets and parking available.

The MCS recommendation for bathing quality is the highest standard of any UK award for bathing water quality. It uses the government agencies' data but applies stricter criteria than those of the EU's higher guideline standards.

The Blue Flag Scheme for beaches

The Blue Flag Scheme is awarded annually to beaches that meet high standards of management, promote environmental care, and have attained high standards for water quality in the previous summer season.

All beaches awarded the Blue Flag must meet the higher EU bathing water standards. The Blue Flag is therefore another useful indicator of good quality bathing water. You can check which beaches have been awarded the Blue Flag.

How can I check the current status of bathing waters?

During the summer months, the Environment Agency posts the results of its weekly tests of bathing water quality in England and Wales on its website.

In Scotland during the summer, SEPA provides daily information on the predicted water quality at 11 of its beaches. These forecasts are available on its website and from a telephone helpline: 0845 230 3098.

Beach safety

A holiday at the seaside is fun for the whole family. An RNLI lifeguard explains what to look out for to stay safe on the beach.

Media last reviewed: 28/05/2015

Next review due: 28/05/2017

Page last reviewed: 15/08/2015

Next review due: 15/08/2017

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