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Area of Outstanding Natural Beauty

Dorset

Polluted by sewage 2,318 times in 2025 - lasting 23,397 hours - That's 2.71 years!

Monitoring fell below 50% in some locations so could be more

Marker shade

Totals for Dorset in 2025

83 Sites polluted by South West Water Wessex Water

2,318 sewage dumps

23,397 hours duration

That's 2.71 years. On average 6.4 times a day

How does Dorset compare?

Dorset was the #3 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

Take Action

Sewage pollution map of Dorset, showing 2,318 overflows in 2025

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Constituencies

Pollution Summary 2025

Here are all the reported sewage overflow totals for Dorset 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 Dorset 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 %
Wessex Water	Sydling Water	SYDLING ST.NICHOLAS WRC	97	2,149	99.9
Wessex Water	South Winterbourne	MARTINSTOWN PS	129	2,029	100
Wessex Water	River Bride	CHICKSBRIDGE PS	112	1,957	99.9
Wessex Water	River Piddle	PUMPING STN ADJACENT THE PIDDLE INN	78	1,753	100
Wessex Water	River Piddle	PUMPING STATION ADJACENT RIVENDELL	76	1,692	100
Wessex Water	River Lydden	BUCKLAND NEWTON WRC	108	1,684	99.6
Wessex Water	River Yeo	HALSTOCK WATER RECYCLING CENTRE	82	1,423	99.8
Wessex Water	River Frome	MAIDEN NEWTON WATER RECYCLING CENTR	41	669	99.8
Wessex Water	River Brit	SOUTHGATE PUMPING STATION	62	637	100
Wessex Water	River Bride	PUNCKNOWLE WRC	43	623	98.8
Wessex Water	Abbotsbury Brook	ABBOTSBURY WWTW	40	616	100
Wessex Water	River Brit	NETHERBURY PUMPING STATION	52	588	99.1
Wessex Water	River Cerne	GODMANSTONE STW	24	545	94.3
Wessex Water	River Frome	NORTH STREET PS	37	539	100
Wessex Water	River Hooke	TOLLER PORCORUM WRC	35	520	100
South West Water	Blackwater River/Stream	HAWKCHURCH STW	37	487	95.7
Wessex Water	River Winniford	CHIDEOCK STW	31	413	100
Wessex Water	River Frome	EVERSHOT WASTEWATER TREATMENT WORKS	45	405	100
Wessex Water	Lyme Bay	BRIDPORT SEWAGE TREATMENT WORKS	52	400	99.9
South West Water	Drimpton Stream	BROADWINDSOR WWTW	40	376	100
Wessex Water	River Parrett	SOUTH PERROTT WWTW	37	341	100
Wessex Water	Sydling Water	SYDLING ST NICHOLAS PUMPING STATION	16	335	100
Wessex Water	River Brit	SOUTH STREET CSO	58	314	94.1
South West Water	River Axe	MOSTERTON PUMPING STATION	72	311	100
South West Water	Temple Brook	DRIMPTON PUMPING STATION	27	270	100
South West Water	River Lim	HORN BRIDGE PSEO/CSO	32	222	100
Wessex Water	Corfe River	CORFE CASTLE STW	27	192	100
Wessex Water	Sea Lagoon Chessel Beach	WEST BEXINGTON PUMPING STATION	26	160	96.4
Wessex Water	River Frome	EVERSHOT COMBINED SEWER OVERFLOW	76	144	100
Wessex Water	River Asker	SOUTH BRIDGE COMB. STORM OVERFLOW	26	96	100
Wessex Water	River Frome	PUMPING STATION AT KING ARMS	22	95	100
Wessex Water	Bridport Harbour	PUMPING STATION AT WEST BAY SLUICES	10	94	100
Wessex Water	Mangerton River	WEST MILTON WATER RECYCLING CENTRE	23	89	100
Wessex Water	Lyme Bay	CHARMOUTH SEWAGE DISPOSAL WORKS	70	76	100
Wessex Water	Swanage Bay	SWANAGE TUNNEL	20	75	100
Wessex Water	Corfe River	GLEBE FARM PUMPING STATION	15	75	100
South West Water	Drimpton Stream	BROADWINDSOR WWTW	55	70	100
Wessex Water	River Asker	LEE LANE PUMPING STATION	15	66	100
Wessex Water	River Brit	BRIDPORT WEST STREET CSO	40	65	89.7
Wessex Water	Halstock Stream	CORSCOMBE WASTEWATER TREATMENT WORK	15	63	100
Wessex Water	River Stour	WATER LANE PUMPING STATION	6	54	100
Wessex Water	River Win	EAST CHALDON PUMPING STATION	10	50	99.9
South West Water	River Axe	WINSHAM WASTEWATER TREATMENT WORKS	94	47	99.2
Wessex Water	Unnamed Stream	HARMAN'S CROSS PUMPING STATION	10	45	99.5
South West Water	Clapton Stream	CLAPTON PUMPING STATION	12	43	100
Wessex Water	Corfe River	CHURCH KNOWLE ANIMAL SANCTUARY PS	9	36	100
South West Water	River Lim	MILL LANE CSO	10	36	8.3
Wessex Water	West Fleet	LANGTON HERRING WRC	38	27	100
Wessex Water	English Channel	OSMINGTON BAY HOLIDAY CENTRE PS	15	27	100
Wessex Water	Lyme Bay	BRIDPORT WATER RECYCLING CENTRE PS	8	26	99.9
Wessex Water	Stream At Winspit Botttom	WORTH MATRAVERS WWTW	19	22	100
Wessex Water	Winniford	SEATOWN PUMPING STATION	6	22	100
Wessex Water	Unnamed Stream To Durlston Bay	DURLSTON ROAD PS	20	19	100
Wessex Water	Tidal River Piddle	WAREHAM WASTEWATER TREATMENT WORKS	7	18	100
South West Water	River Lim	GUN CLIFF PUMPING STATION	4	18	100
Wessex Water	English Channel	WEST LULWORTH PUMPING STATION	8	17	100
Wessex Water	River Frome	SOUTH EAST PUMPING STATION	10	16	100
Wessex Water	Corfe River	RED LANE PUMPING STATION	6	16	100
Wessex Water	River Bride	SHIPTON GORGE PUMPING STATION	4	15	99.8
Wessex Water	Poole Harbour	HOLTON HEATH WW PUMPING STATION	6	14	100
Wessex Water	Mill Stream	CHURCH STREET PUMPING STATION	10	12	100
Wessex Water	River Asker Via Sws	FISHWEIR FIELDS PS	3	11	100
Wessex Water	River Brit	HAMS PATH COMBINED SEWER OVERFLOW	12	11	100
Wessex Water	Corfe River	STUDLAND ROAD PUMPING STATION	10	11	99.9
Wessex Water	River Swan	HERSTON CROSS ATTENUATION TANK CSO	6	10	100
Wessex Water	Little Sea	WADMORE LANE PUMPING STATION	4	9	99.8
South West Water	River Synderford	THORNCOMBE WWTW	8	8	100
Wessex Water	River Frome	STOBOROUGH RIDGE PUMPING STATION	3	8	99.9
Wessex Water	Ulwell Stream	NEW SWANAGE ATTENUATION TANK	4	7	100
Wessex Water	River Frome	WAREHAM COMBINED SEWER OVERFLOW	6	7	100
Wessex Water	River Bride	BURTON BRADSTOCK	4	7	100
Wessex Water	River Brit	WEST BRIDGE CSO	11	6	99.3
Wessex Water	Unnamed Stream	RINGSTEAD STW	1	5	99.9
Wessex Water	Lyme Bay	CHARMOUTH SEWAGE DISPOSAL WORKS	2	4	100
Wessex Water	River Frome	EAST KNIGHTON PUMPING STATION	1	4	100
Wessex Water	River Iwerne	SHROTON PUMPING STATION	1	4	100
Wessex Water	Studland Bay	COOMBE PUMPING STATION	5	4	100
Wessex Water	English Channel	LULWORTH BEACH PUMPING STATION	7	1	100
South West Water	River Lim	JERICHO CSO	8	1	100
South West Water	River Lim	GOSLINGS BRIDGE CSO	3	0	95.8
Wessex Water	Swanage Bay	SWANAGE TUNNEL	1	0	100
Wessex Water	Swanage Bay	SWANAGE TUNNEL	1	0	100
Wessex Water	River Asker	EAST BRIDGE COMBINED SEWER OVERFLOW	2	0	100

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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