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