Seawater monitoring

Why we monitor seawater

We monitor seawater:

to ensure compliance with the EU Bathing water directive
information on Jerseys seawater safety for swimming and recreational use
identifying episodes of pollution and ensuring compliance with Water Pollution (Jersey) Law 2000
valuable information for Jersey residents and tourists on the quality of Jerseys seawater
providing information to the aquaculture industry, such as oyster or mussel farming

The people involved in seawater monitoring and their contact details:

officers from the Water and Air team Tel +44 (0) 1534 441600
officers from the Environmental Protection team +44 (0) 1534 709535
Environmental Health who in consultation can advise on the safety of swimming if we have poor results. Tel +44 (0) 1534 445808
the Official Analyst’ laboratory staff who carry out the analysis. Tel +44 (0) 1534 736455

The monitoring of seawater provides valuable public health data, however it is only a snap-shot of the water quality at the time of sampling and bathers and other recreational users enter coastal waters at their own risk. General public health advice is to avoid swimming for 48 hours following heavy rainfall and to avoid seafoam if present.

If you notice pollution on the beach or in the sea, call +44 (0) 1534 709535.

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Open seawater results map

Open seawater results table

Non-routine sampling

We may sometimes undertake additional sampling if there are concerns about the quality of the bathing water.

Bathing water classifications

Bathing classification	Criteria
	Excellent water quality Indicates this sample meets the following standard: less than or equal to 250 Escherichia coli per 100ml less than or equal to 100 Intestinal enterococci per 100ml
	Good water quality Indicates this sample meets the following standard: less than or equal to 500 Escherichia coli per 100ml less than or equal to 200 Intestinal enterococci per 100ml
	Poor water quality Indicates values are above 500 Escherichia coli per 100ml and above 200 Intestinal enterococci per 100ml

Bathing classification

Criteria

Excellent water quality

Indicates this sample meets the following standard:

less than or equal to 250 Escherichia coli per 100ml
less than or equal to 100 Intestinal enterococci per 100ml

Good water quality

Indicates this sample meets the following standard:

less than or equal to 500 Escherichia coli per 100ml
less than or equal to 200 Intestinal enterococci per 100ml

Poor water quality

Indicates values are above 500 Escherichia coli per 100ml and above 200 Intestinal enterococci per 100ml

Monitoring schedule

We monitor seawater from Tuesday 13 May to Tuesday 24 September as part of the EU Bathing Water Directive. You can find the most recent results on the map and table above.

We submit our results to the Marine Conservation Society to be included in the UK Good Beach Guide.

Month	Date
May	13 and 14 May 2025
May	19 and 20 May 2025
May	27 and 28 May 2025
June	2 and 3 June 2025
June	9 and 10 June 2025
June	16 and 15 June 2025
June	21 and 22 June 2025
June	28 and 29 June 2025
July	7 and 8 July 2025
July	14 and 15 July 2025
July	21 and 22 July 2025
July	28 and 29 July 2025
August	4 and 5 August 2025
August	11 and 12 August 2025
August	18 and 19 August 2025
August	26 and 27 August 2025
September	1 and 2 September 2025
September	8 and 9 September 2025
September	15 and 16 September 2025
September	23 and 24 September 2025

List of bays we monitor

We monitor 16 bays around Jersey:

St Brelade Bay
Beauport
Portelet
Le Braye
Plémont
Greve de Lecq
Watersplash, St Ouen's Bay
Bonne Nuit
La Haule
Victoria Pool, St Aubin's Bay
Grouville
Archirondel
Havre des Pas
Green Island
Bouley Bay
Rozel

To ensure accuracy and consistency, a duplicate sample and analysis is done each week by the Official Analysts laboratory.

Water safety for swimming

We provide the seawater data to Environmental Health every week. They analyse the data and consult other stakeholders to make a decision on whether to advise against swimming in specific bays.

If the results are poor, they would notify the media and signage would be displayed at the relevant bays.

Jersey has some of the cleanest water in Europe. Poor seawater quality can happen after periods of heavy rain. You should wait at least 48 hours before you swim after bad weather. This is irrespective of the formal samples taken and analysed by Government.

Sea Foam

We want to highlight that the public health advice is to avoid contact or ingestion of sea foam. Sea foam forms naturally when waves agitate organic matter in seawater, but it can also contain substances that are harmful to health.

These substances can irritate the skin, upset the stomach, or affect breathing, especially in children and pets.

To contact Environmental Health call +44 (0)1534 445808 or email environmentalhealth@gov.je.

New signs to be fitted at the bathing water bays

New signs have been designed and are to be fitted in the next month or so at each monitoring site which provide a QR code which links to the website. An example of a sign is shown below.

Seawater profiles for each bay

A profile has been produced for Jersey's monitored seawaters.

Each profile includes:

a photograph, description, map of the seawater and surrounding area
an identification of potential sources of pollution and measures to reduce pollution
the phone number to report water pollution and contact details for more information

Archirondel seawater profile