Area of Outstanding Natural Beauty

Cornwall

Polluted by sewage 2,647 times in 2025 - lasting 24,391 hours - That's 2.82 years!

Marker shade

Totals for Cornwall in 2025

79 Sites polluted by South West Water

2,647 sewage dumps

24,391 hours duration

Sewage pollution map of Cornwall, showing 2,647 overflows in 2025

That's 2.82 years. On average 7.3 times a day

How does Cornwall compare?

Cornwall was the #2 most polluted Area of Outstanding Natural Beauty in England & Wales, by duration of sewage overflows, as reported by the water companies

Why the change?

Storm overflows spill when it rains, and 2025 was drier than 2024 - 90% of average annual rainfall against 105%.

So much of any drop is weather, not fixed pipes. The live page shows rainfall and sewage side by side, day by day.

Live Data

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Constituencies

Pollution Summary 2025

Here are all the reported sewage overflow totals for Cornwall in 2025.

How we count, and how accurate it is

A CSO Combined Sewage Overflow - a device that, when operating, pours combined rainwater & sewage into a waterway counts towards Cornwall when it sits inside the designated area, or within 200 metres of its boundary. An overflow close to two AONBs is counted in both.

We use data from the water companies, but we are seeing many anomalies that make us believe that location information is quite poor. The situation is likely far worse than reported here.

Other CSO Combined Sewage Overflow - a device that, when operating, pours combined rainwater & sewage into a waterway s just outside the 200 metre boundary are not counted, though they may still affect water quality inside the area.

Company	Waterway	Site	Sewage Dumps	Duration (Hours)	Reporting %
South West Water	Penpont Water	ALTARNUN STW (STORM TANK)	165	3,294	100
South West Water	Atlantic / Porth Nanven Stream	COT VALLEY PUMPING STATION	100	2,056	100
South West Water	Mylor Creek	MYLOR BRIDGE WWTW	83	1,699	100
South West Water	River Fowey	COMMONMOOR STW	127	1,589	100
South West Water	River Loveny	CHAPEL CAR PARK PSCSO/EO	82	1,489	99.9
South West Water	Mother Iveys Bay	ST MERRYN COMBINED SEWER OVERFLOW	107	1,380	100
South West Water	St Austell Bay	POLKERRIS FINE SCREENING PLANT & PS	59	913	100
South West Water	Stream	BOJEWYAN PSCSO/EO	47	872	100
South West Water	Little Petherick Creek	LITTLE PETHERICK WWTW	112	815	99.7
South West Water	English Channel	THE LIZARD PUMPING STATION	54	693	99.9
South West Water	Truro River Estuary	NEWHAM WASTEWATER TREATMENT WORKS	51	668	100
South West Water	River Fowey Estuary	TOWN QUAY PUMPING STATION	198	634	100
South West Water	Unknown	PERRANUTHNOE PUMPING STATION	50	565	100
South West Water	Fowey Estuary	FOWEY WASTEWATER TREATMENT WORKS	72	556	100
South West Water	Trevone Bay	TREVONE PUMPING STATION	23	441	99.4
South West Water	Peneont Water	WAR MEMORIAL PSCSO/EO	25	432	100
South West Water	Carne Stream	VERYAN STW	21	408	100
South West Water	Atlantic Ocean, Off Porthcurno	PORTHCURNO VALLEY PUMPING STATION	24	394	100
South West Water	Mylor Creek	MYLOR BRIDGE PSCSO/EO	38	390	100
South West Water	Atlantic Ocean	GORRAN HAVEN PSCSO/EO	50	387	96.1
South West Water	Cawsand Bay Estaurine Via Sws	CAWSAND SOUTH PUMPING STATION	29	354	100
South West Water	River Cober	HELSTON WWTW	32	340	97.4
South West Water	Unknown	TREKNOW STW	17	296	100
South West Water	River Fowey Estuary	GOLANT PUMPING STATION	93	288	100
South West Water	Tregaseal Stream	St Just (Tregeseal 1)	18	274	100
South West Water	English Channel	HELLARCHER PUMPING STATION	74	245	100
South West Water	Atlantic Ocean,Off Sennen Cove	SENNEN COVE PUMPING STATION	21	223	99.2
South West Water	Pill Creek	LOWER TREVILLA PUMPING STATION	26	223	100
South West Water	Atlantic Ocean	TINTAGEL CASTLE ROAD PUMP STATION	26	215	100
South West Water	Atlantic Ocean	BOSSINEY BACK LANE PUMPING STATION	22	206	100
South West Water	River Kenwyn	ECHO CORNER PSCSO/EO	16	159	100
South West Water	Unknown	ST KEVERNE STW	22	143	100
South West Water	Treyarnon Stream	TREHEMBORNE PS	22	140	100
South West Water	Atlantic Ocean Coastal	GEEVOR MINE PUMPING STATION	31	129	100
South West Water	Atantic Ocean	LOWER BOSCASWELL CSO	72	119	100
South West Water	Portmellon Stream	GORRAN CHURCHTOWN PUMPING STATION	30	117	100
South West Water	River Fowey Estuary	CAFFA MILL PUMPING STATION	38	106	100
South West Water	River Lynher	NORTH HILL WWTW	19	99	98.4
South West Water	Coverack Cove	COVERACK MILL PS	24	99	98.6
South West Water	Church Cove	CHURCH COVE ROAD PS	13	91	100
South West Water	Atlantic / Porth Nanven Stream	BOSORNE ROAD SEWER OVERFLOW	43	90	98.4
South West Water	Cawsand Bay	KINGSAND SEWAGE PUMPING STATION	21	84	95.8
South West Water	English Channel	CADGWITH NEW ROAD PSCSO/EO	10	66	100
South West Water	Atlantic Ocean	BOTALLACK PUMPING STATION	37	63	100
South West Water	Mounts Bay	PORTHLEVEN HARBOUR ATTENUATION	13	53	100
South West Water	Local Stream	NANCHERROW HILL CSO	30	49	93.5
South West Water	Cawsand Bay	KINGSAND SEWAGE PUMPING STATION	44	37	95.9
South West Water	Unknown	ST GENNYS STW	19	34	99.7
South West Water	Mevagissey Bay	MEVAGISSEY PS	22	31	100
South West Water	St Austell River	ST AUSTELL (LONDON APPRENTICE) PS	3	28	100
South West Water	Penryn River	FLUSHING PUMPING STATION	12	23	100
South West Water	Coombe Valley Str	STIBB SEWAGE TREATMENT WORKS	14	22	100
South West Water	Atlantic Ocean	BOSWEDDEN PUMPING STATION	8	22	100
South West Water	Mounts Bay	MOUSEHOLE PUMPING STATION	31	22	100
South West Water	Carrick Roads	ST MAWES NO.1 PS	34	22	100
South West Water	Trevaunance Stream	COVE PUMPING STATION	23	21	100
South West Water	River Tinney	CALENICK PUMPING STATION	6	17	100
South West Water	Haven, Atlantic Ocean	PORT ISAAC PUMPING STATION	16	15	100
South West Water	Mylor Creek	MYLOR BRIDGE WWTW	4	14	100
South West Water	English Channel	POLPERRO WWTW	12	14	100
South West Water	River Lerryn	LERRYN CAR PARK OVERFLOW	19	13	100
South West Water	Polurrian Cove	MULLION TRANSFER PS	9	11	100
South West Water	Atlantic / Porth Nanven Stream	BOSORNE ROAD SEWER OVERFLOW	13	10	100
South West Water	Camel Estuary	PADSTOW HARBOUR PUMPING STATION	3	9	100
South West Water	English Channel	LAFLOUDER LANE PUMPING STATION	1	9	100
South West Water	Camel Estuary	PORTHILLY COVE PUMPING STATION	5	8	100
South West Water	Mounts Bay English Channel	MOUSEHOLE HARBOUR (SOUTH SLIP) CSO	17	7	100
South West Water	Coastal Stream	PORT GAVERNE CSO	9	6	100
South West Water	Atlantic Ocean	BOSCASTLE HARBOUR PUMPING STATION	5	5	100
South West Water	River Fowey Estuary	READYMONEY COVE PS	2	2	100
South West Water	White River	NANSLADRON PUMPING STATION	2	1	100
South West Water	Coverack Cove	COVERACK HARBOUR PSEO/CSO	7	1	99.2
South West Water	St Austell River	PENTEWAN PSCSO/EO	2	1	100
South West Water	River Fowey Estuary	WHITEHOUSE SLIP (POINT) CSO	7	1	100
South West Water	River Fowey Estuary	BODINNICK COMBINED SEWER OVERFLOW	3	1	100
South West Water	Pencabe Drang	PORTSCATHO SEWAGE TREATMENT WORKS	3	0	97.1
South West Water	Porthallow Stream	PORTHALLOW SEWAGE PUMPING STATION	1	0	100
South West Water	Port Issac Bay, Atlantic	PORT ISAAC WWTW CSO	3	0	100
South West Water	Cawsand Bay	NORTH ROCK SEWAGE PUMPING STATION	1	0	95.8

Data Sources & Accuracy

EDM (Event Duration Monitoring) data and Consented Discharges to Controlled Waters with Conditions from Environment Agency & Data Map Wales, and Scottish Water

Experimental derived data from Thames Water API, Some data may be missing or inaccurate. Live sewage data from Stream Water API

Annual figures up to and including 2025 come from official water company returns. The 2026 figure is our own estimate, derived continuously from the companies' live data feeds.

Uses Environment Agency rainfall data from the real-time data API (Beta) - Rainfall data is delayed by up to two days.

This website is intended to provide an accurate representation of the Environment Agency data. The data is hard to use, and thus some errors may have been made. If you find something that is incorrect, please raise an issue at the GitHub issues page and we'll endeavour to fix it quickly.

This project is not associated, approved or endorsed by any of the companies whose logos you see here.

Analysing sewage pollution by the Water Industry

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