Beach
Caswell Bay
Excellent
Official rating · 2025 seasonThe highest rating under the bathing water standards.
Ratings are calculated from up to four years of samples, so they describe the site over time rather than the water today.
Water quality can be affected by heavy rain
Water sampled 3 Aug 2026
· 3 weeks agoOne sample taken on that date, not a live reading. Water quality changes day to day, especially after heavy rain.
E. coli
<10 cfu/100ml
At or below the laboratory's reporting limit.
Normal levels
At or below the level required for the highest rating.
Excellent here is 250 or below, Good up to 500 · coastal limits
What is E. coli?
A bacterium that lives in the gut of people and animals, so finding it in water means sewage or livestock run-off has reached it. Most strains will not hurt you; they are counted because whatever else came in with them might.
The limits above are percentiles across a whole season's samples, not an average, so a single high reading does not by itself change the site's rating.
Intestinal enterococci
<10 cfu/100ml
At or below the laboratory's reporting limit.
Normal levels
At or below the level required for the highest rating.
Excellent here is 100 or below, Good up to 200 · coastal limits
What is Intestinal enterococci?
The other bacterium the regulations require, and the more telling one at the coast: it survives in salt water far longer than E. coli, so it still shows contamination that E. coli alone would miss.
The limits above are percentiles across a whole season's samples, not an average, so a single high reading does not by itself change the site's rating.
Why this matters if you are swimming
You are most likely to get ill from swallowing the water, and most likely to notice it as a stomach upset. Ear, eye, chest and skin infections are the other common outcomes. Open cuts and dunking your head both raise the odds.
The risk is worst in the day or two after heavy rain, when storm overflows discharge and run-off washes off fields — often at sites that rate Excellent the rest of the season.
These counts come from one sample, taken by hand on 3 Aug 2026 and analysed in a lab. They describe the water on that day, not the water in front of you now.
Pollution risk
No pollution forecast
Natural Resources Wales does not publish a daily pollution forecast for this site.
How does this work?
After heavy rain, storm drains and sewage overflows can temporarily contaminate the water. Sampled weekly through the bathing season. Where a daily forecast exists it predicts risk a day ahead and expires after that.
Classification history
Each year's grade is calculated from all samples taken across that bathing season, under the Bathing Water Directive.
Natural Resources Wales · Caswell Bay · 66 m away
Published under Open Government Licence v3.0 · © Natural Resources Wales
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Frequently asked questions
Where does the water quality data come from?
From the official agency for the country the spot is in: the Environment Agency in England, Natural Resources Wales, SEPA in Scotland, DAERA in Northern Ireland, the EPA in Ireland, and the European Environment Agency elsewhere. All of them test for E. coli and intestinal enterococci under the same Bathing Water Directive standard.
How often is water quality updated?
Designated bathing waters are sampled roughly weekly through the bathing season, and the annual classification is recalculated once a year from the previous four seasons. Some agencies also publish a daily pollution forecast; where one exists it is shown alongside the samples.
What do the classifications mean?
Excellent and Good are the top classifications, based on measured bacteria levels. Sufficient meets the minimum standard. Poor means the water failed it. The classification covers the last four seasons, so it describes a site in general rather than the water today — always check conditions yourself before swimming.
Why do some beaches have pollution warnings?
Heavy rainfall can cause sewage overflows and wash contaminants off the land. Where an agency models that risk it issues a short-term warning, and some also publish bathing restrictions when an incident occurs.
Why does this spot show more than one monitoring site?
Some spots sit near several official sites — two adjacent designated beaches, for instance. Each is listed with how far it is from the spot, nearest first.