Is this river or lake fit to swim in today?

Is this river, lake or beach fit to swim in today — on the evidence?

Only designated bathing waters are tested, their classification is four seasons old by design, and what was discharged upstream this week sits on eleven separate water-company maps that keep no history. This page puts the four things that are actually measured on one map — the Environment Agency classification, its daily pollution-risk forecast, the latest bacterial sample, and every monitored storm overflow within 5 km from our own 30-minute archive — and turns them into one transparent score. Click anywhere for the evidence near that spot, tested or not. A 5 km radius is not a flow path, a score is a heuristic, and none of this is medical advice.

464

designated bathing waters in England, all scored

12 of 14

classified river sites are rated Poor by the EA

of 38 rivers and lakes score green right now

inland sites had a storm overflow discharge within 5 km in the last 7 days

Good on the evidence (70+)Caution (45–69)Avoid on the evidence (under 45)click a dot for its score · click anywhere else to check that spotupdated 00:37 UK time

Download everything: CSV · JSON — one row per site with the score, its parts and every input.

Every river and lake site, best first

All 38 inland designated bathing waters. Click a name to jump to it on the map. Green ≥70, amber 45–69, red under 45.

Site	Score	Class	E. coli	Sampled	Forecast	Overflows ≤5 km	Spilled 7 d
Rutland Water Whitwell Creek Lake · Rutland	90	Excellent	10	11 Sept	normal	0	0
Windermere, Lakeside YMCA Lake · Westmorland and Furness	90	Excellent	10	13 Sept	normal	0	0
Rutland Water Sykes Lane Lake · Rutland	90	Excellent	27	11 Sept	normal	0	0
Cotswold Country Park and Beach Lake · Cotswold	90	Excellent	36	6 Sept	normal	1	0
Hampstead Heath (Mixed Pond) Lake · City and County of the City of London	90	Excellent	110	15 Sept	normal	13	0
Hampstead Heath (Mens Pond) Lake · City and County of the City of London	90	Excellent	170	15 Sept	normal	14	0
Henleaze Lake Lake · City of Bristol	90	Excellent	190	15 Sept	normal	127	0
Colwick Country Park (West Lake) Lake · City of Nottingham	80	Excellent	10	7 Sept	normal	37	5
Windermere, Rayrigg Meadow Lake · Westmorland and Furness	80	Excellent	10	13 Sept	normal	3	2
Windermere, Millerground Landing Lake · Westmorland and Furness	80	Excellent	27	13 Sept	normal	2	1
Windermere, Fellfoot Lake · Westmorland and Furness	80	Excellent	55	13 Sept	normal	2	1
Frensham Great Pond Lake · Waverley	80	Excellent	230	10 Sept	normal	2	0
Friars Meadow, River Stour River · Babergh	75	Good	130	15 Sept	normal	2	0
Pangbourne Meadow, River Thames River · Pangbourne Parish	70	new	91	11 Sept	—	1	0
Coniston Water, Monk Coniston Lake · Westmorland and Furness	65	Good	82	13 Sept	normal	2	2
Coniston Water, Brown Howe Lake · Westmorland and Furness	65	Good	110	13 Sept	normal	1	1
Hampstead Heath (Ladies Pond) Lake · City and County of the City of London	65	Good	590	15 Sept	normal	15	0
Wallingford Beach, River Thames River · South Oxfordshire	55	Sufficient	150	11 Sept	normal	3	0
Falcon Meadow, River Waveney River · East Suffolk	50	new	160	8 Sept	—	7	1
Swale above Richmond Falls River · North Yorkshire	50	new	610	9 Sept	—	15	0
Ham and Kingston, River Thames River · Kingston upon Thames	50	new	770	15 Sept	—	10	0
The Serpentine - Hyde Park Lake · City of Westminster	45	Good	560	15 Sept	normal	29	1
Sandy Lane, Chester River · Cheshire West and Chester	40	new	630	15 Sept	—	39	10
Coniston Water, Boating Centre Lake · Westmorland and Furness	35	Sufficient	320	13 Sept	normal	3	3
River Avon at Queen Elizabeth Gardens River · Wiltshire	35	new	1600	15 Sept	—	8	0
River Severn at Ironbridge River · Telford and Wrekin	25	Poor	300	8 Sept	normal	19	0
Wolvercote Mill Stream River · Oxford	25	Poor	310	11 Sept	normal	3	0
River Avon at Fordingbridge River · New Forest	25	Poor	470	15 Sept	normal	3	0
River Frome at Farleigh Hungerford River · Somerset	15	Poor	340	15 Sept	normal	24	0
Sheep's Green, River Cam River · Cambridge	15	Poor	420	14 Sept	normal	2	0
Nidd at the Lido, Knaresborough River · North Yorkshire	15	Poor	670	14 Sept	normal	24	0
River Severn in Shrewsbury River · Shropshire	5	Poor	170	8 Sept	normal	48	1
River Tone at French Weir Park River · Somerset	5	Poor	550	14 Sept	normal	25	1
River Ribble at Edisford Bridge River · Ribble Valley	5	Poor	580	10 Sept	normal	10	8
Derwent Water at Crow Park Lake · Cumberland	5	Poor	630	13 Sept	normal	8	2
River Teme in Ludlow River · Shropshire	0	Poor	110	8 Sept	increased	7	0
Wharfe at Cromwheel, Ilkley River · Bradford	0	Poor	620	14 Sept	normal	14	1
Wharfe at Wilderness Carpark River · Leeds	0	Poor	1300	14 Sept	normal	13	1

The coast, top and bottom ten

426 coastal sites; the full list is in the CSV. Scores cluster near the top because most beaches are Excellent — the bottom ten are where the attention belongs.

Site	Score	Class	E. coli	Sampled	Forecast	Overflows ≤5 km
Anstey's Cove (Torquay) Coast · Torbay	90	Excellent	10	14 Sept	normal	17
Babbacombe Coast · Torbay	90	Excellent	10	14 Sept	normal	17
Bamburgh Castle Coast · Northumberland	90	Excellent	10	15 Sept	normal	3
Beacon Cove Coast · Torbay	90	Excellent	10	14 Sept	normal	25
Bigbury-on-Sea North Coast · South Hams	90	Excellent	10	8 Sept	normal	9
Bigbury-on-Sea South Coast · South Hams	90	Excellent	10	1 Sept	normal	10
Birling Gap Coast · Wealden	90	Excellent	10	10 Sept	normal	1
Booby's Bay Coast · Cornwall	90	Excellent	10	15 Sept	normal	3
Bournemouth Alum Chine Coast · Bournemouth, Christchurch and Poole	90	Excellent	10	26 Aug	normal	9
Bournemouth Boscombe Pier Coast · Bournemouth, Christchurch and Poole	90	Excellent	10	10 Sept	normal	14

…and the bottom ten:

Site	Class	E. coli	Sampled	Forecast	Overflows ≤5 km	Spilled 7 d
Southsea East Coast · City of Portsmouth	Poor	750	15 Sept	normal	23	0
Lyme Regis Church Cliff Beach Coast · Dorset	Poor	700	8 Sept	normal	11	0
Haverigg Coast · Cumberland	Poor	580	11 Sept	normal	3	0
Blackpool Central Coast · Blackpool	Sufficient	570	6 Sept	increased	7	1
Blackpool South Coast · Blackpool	Sufficient	560	6 Sept	increased	7	1
Littlestone Coast · Folkestone and Hythe	Poor	540	10 Sept	normal	2	0
Blackpool North Coast · Blackpool	Poor	540	6 Sept	increased	9	1
Steamer Quay, Dart Estuary Coast · South Hams	Poor	450	7 Sept	normal	22	2
Porthluney Coast · Cornwall	Sufficient	350	9 Sept	increased	4	0
Tynemouth Cullercoats Coast · North Tyneside	Poor	340	10 Sept	normal	39	0

What we found

The kill criterion for this piece was simple: if the EA’s own classification already told swimmers what they need to know, there would be nothing to add. It does not, twice over. First, the rivers: of the 14 river bathing waters with a classification, 12 are Poor — River Severn at Ironbridge, Wolvercote Mill Stream, River Avon at Fordingbridge, River Frome at Farleigh Hungerford, Sheep's Green, River Cam, Nidd at the Lido, Knaresborough, River Severn in Shrewsbury, River Tone at French Weir Park, River Ribble at Edisford Bridge, River Teme in Ludlow, Wharfe at Cromwheel, Ilkley, Wharfe at Wilderness Carpark. The exceptions: Friars Meadow, River Stour (Good), Wallingford Beach, River Thames (Sufficient). Under the Bathing Water Regulations a Poor site must carry advice against bathing all season, so the designation that campaigners fought for has, at most river sites, produced a sign saying don’t.

The lakes are the positive control. 12 of the 18 classified lake sites are Excellent — the same sampling regime, the same thresholds, the same summer — so the river result is about rivers, not about the test.

Second, the classification is a four-season statistic, and the live picture moves daily. Today the EA forecasts increased pollution risk at 7 sites (Exmouth, Weston Main, River Teme in Ludlow, Porthluney, Blackpool North, Blackpool South, Blackpool Central). Our overflow archive, which began on 5 August 2026, has seen a storm overflow discharge within 5 km of 16 of the 38 inland sites in the last 7 days. None of that is visible on the classification, and none of it is on the EA page either.

Does the overflow term earn its place? We pre-registered one test and print it whichever way it falls: the median of the latest fresh E. coli reading at sites that had a discharge within 5 km in the last 7 days, against sites that did not, across every site. No difference: the median latest E. coli at the 162 sites with a discharge within 5 km in the last 7 days is 10 cfu/100 ml, against 10 at the 300 without. Both groups sit at the 10 cfu/100 ml reporting floor — the EA reports anything below detection as 10.

The all-sites test is dominated by beaches, where dilution is enormous and most readings are at the floor, so we also print the same statistic over rivers and lakes only — exploratory, decided after seeing the first result, and labelled so. Supports the overflow term: the median latest E. coli at the 16 inland sites with a discharge within 5 km in the last 7 days is 245 cfu/100 ml, against 210 at the 22 without. A radius is a crude proxy for a flow path, so this is consistent with, not proof of, overflows driving readings. Either way the penalty stays in the score: it is a precaution about raw sewage in the water this week, not a prediction about last week’s sample, and the two are measured days apart.

How the score works

One number per site, 0–100, built from four measured inputs in a fixed order. Every site’s popup shows the parts so the arithmetic can be checked by eye, and the CSV carries them all.

Start from the annual classification. Excellent 90, Good 75, Sufficient 55, Poor 25. A newly designated, not-yet-classified site starts at 60, provisionally. The classification is the EA’s four-season statistical verdict (95th and 90th percentiles of E. coli and intestinal enterococci) and nothing live overrides it — it anchors the score.
Adjust for the latest sample, if it is fresh. A sample within the last 45 days nudges the score against the Directive’s single-sample yardsticks: worse than the Good threshold −25, between Excellent and Good −10, inside the Excellent band 0 (+10 for an unclassified site). Inland the yardsticks are 500/1,000 E. coli and 200/400 enterococci per 100 ml; on the coast 250/500 and 100/200. A sample older than 45 days is shown but not scored.
Apply the EA’s own daily forecast. Where the Agency predicts increased pollution risk today — its model of rain, tide, wind and sunlight at that site — −30.
Apply the storm overflows within 5 km, worst tier only. Any discharging right now −30; otherwise any discharge in the last 48 hours −20; otherwise any in the last 7 days −10. From our archive of every monitored overflow in England, sampled every 30 minutes, plus the companies’ own latest-event timestamps.

Clamp to 0–100. 70 and above is Good on the evidence; 45–69 is Caution; under 45 is Avoid on the evidence. The weights are judgement, not regression — they are chosen so that a Poor classification alone is red, an Excellent site with a live discharge nearby drops to amber, and an Excellent site with a bad fresh sample and a discharge drops to red. You may disagree with them; the inputs are all on the page so you can re-weight them yourself.

What the evidence says about getting ill

Gastrointestinal illness is well evidenced. A prospective study of competitors in open-water events on the River Thames found a significantly higher rate of gastrointestinal illness among swimmers than among non-swimming companions, rising with the amount of water swallowed (Hall et al., Epidemiology & Infection 2017, doi:10.1017/S0950268816003393). Surfers Against Sewage logged 1,853 sickness reports through its Safer Seas & Rivers Service in its 2024 reporting year. The mechanism is not mysterious: E. coli and enterococci are measured precisely because they track faecal pathogens — norovirus, Campylobacter, Cryptosporidium — and ingestion is the route.

Gynaecological and urinary infection is plausible but thinly measured. Surveys of women who swim outdoors report urinary tract infections and thrush among the ailments they attribute to swimming, and a study of river bathing in the Democratic Republic of Congo found a raised odds of urinary tract infection among bathers. We could find no UK study that quantifies it, and we would rather say so than inflate a mechanism into a statistic. If you are prone to UTIs, the sensible precautions — change out of a wet costume promptly, rinse, drink water — cost nothing.

Limits, stated plainly

Designated sites only are tested. A click anywhere else shows what is measured nearby, not a reading of that water.
5 km is a radius as the crow flies, not a flow path. An overflow downstream cannot reach you; an overflow upstream can, and so can one 20 km upstream that the radius never sees.
Not every overflow has a monitor, and the companies’ live feeds drop out. Offline is recorded as offline, never as clean. Our archive began on 5 August 2026; “last discharge” also uses the companies’ own latest-event timestamps, which can predate it.
The sample shown is the latest published; the EA samples weekly in season and results lag by days. Samples older than 45 days are not scored.
England only — Wales, Scotland and Northern Ireland publish their bathing-water data separately.
Agricultural runoff, septic tanks, wildlife and blue-green algae are real hazards that no term in this score measures.

Is it safe to swim here today?

We cannot tell you that, and nobody honestly can. What we can show is everything that is measured: the site’s four-season classification, the Environment Agency’s own daily pollution-risk forecast, the most recent bacterial sample and every monitored storm overflow within 5 km with what it has discharged this week. Green means the evidence is good; red means it is bad; amber means mixed. Swallowing river water is the main route to illness, so the usual advice — keep your mouth shut, cover cuts, avoid 48 hours after heavy rain, wash hands before eating — applies everywhere, including green sites.

Why does my favourite swim spot not appear?

Only designated bathing waters are sampled by the Environment Agency, and England has a few hundred of them — 38 inland. Everywhere else is untested, so there is no classification, no forecast and no sample to show. That is exactly why the map lets you click anywhere: for an untested spot we show the nearest tested sites and the storm overflows within 5 km from our own archive, which is the only live evidence that exists for it.

Why are so many river sites Poor when the lakes are Excellent?

Rivers receive treated effluent continuously and untreated storm overflows when it rains, and they carry the runoff of the whole catchment above the site — livestock, roads, septic tanks. A lake dilutes and settles what reaches it. The classification is statistical over four seasons, so a river that is fine on a dry July day and sewage-laden after a wet weekend will still be Poor. That is the same reason the classification alone is not enough to judge today.

What does the storm-overflow number actually mean?

It is a radius, not a flow path: the count of monitored storm overflows within 5 km of the site as the crow flies, and how many of them our archive saw discharging now, in the last 48 hours and in the last 7 days. An overflow downstream of you cannot reach you; one upstream can. Sewage in a river dilutes and dies off over hours to days depending on flow and sunlight, which is why the penalty decays with time. Not every overflow has a monitor, and water-company feeds have gaps and outages, which we record as offline rather than as clean.

Does wild swimming cause gynaecological or urinary infections?

The gastrointestinal link is well evidenced — cohort studies of river swimmers show raised rates of diarrhoea and vomiting after events, and the swimming charities log thousands of sickness reports a year. The gynaecological and urinary side is much thinner: surveys of women who swim outdoors report UTIs and thrush, one African study of river bathing found a raised odds of urinary infection, but we could find no UK study that measures it. We say so rather than dress a plausible mechanism up as a finding.

Sources: Environment Agency Bathing Water Quality data — classifications, pollution-risk forecasts, sample results and site profiles (OGL v3.0; each site links to its EA profile). Storm overflow status from the water companies’ event-duration-monitoring feeds, archived by Novarly every 30 minutes. Geocoding: postcodes.io and OpenStreetMap Nominatim (ODbL). Basemaps: OpenFreeMap / OpenMapTiles / OpenStreetMap contributors; satellite imagery © Esri. Hall et al. 2017 doi:10.1017/S0950268816003393; Surfers Against Sewage Water Quality Report 2024. This is a transparent heuristic over public monitoring data, not a health assessment and not medical advice; if you are ill after swimming, see a doctor and report it to the EA and to Surfers Against Sewage.

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