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Government of Jerseygov.je

Information and public services for the Island of Jersey

L'înformâtion et les sèrvices publyis pouor I'Île dé Jèrri

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:

  1. officers from the Water and Air team Tel +44 (0) 1534 441600
  2. officers from the Environmental Protection team  +44 (0) 1534 709535
  3. Environmental Health who in consultation can advise on the safety of swimming if we have poor results.  Tel +44 (0) 1534 445808
  4. 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 3 Stars

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 3 Stars

​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 3 Stars​

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
  • PlĂ©mont
  • 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 fo​r 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

Beauport seawater profile

Bonne Nuit seawater profile

Bouley Bay seawater profile

Green Island seawater profile

Greve de Lecq seawater profile

Grouville seawater profile

Havre des Pas seawater profile

La Haule seawater profile

Le Braye seaw​ater profile

Plémont seawater profile

Portelet seawater profile

Rozel seawater profile

St Brelade's Bay seawater profile

Victoria Pool seawater profile​

Watersplash seawater profile

​When sea water quality monitoring started

Monitoring started in 1992. We now classify our beaches following guidance from the European Directive and by the World Health Organisation. 

From 2015 bathing water classifications throughout Europe are based on sampling data collected over 4 years. 

Historic data is available from Natural Environment. Call +44 (0) 1534 441600 or email environment@gov.je.

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