Overflow history upstream of Pangbourne Meadow, River Thames

The spot's forecast · For event organisers

This page lists the monitored storm overflows upstream of this spot and how often each spilled in each year. It is not a water test, and it does not say whether the water is fit to swim in. It does not include farm runoff, misconnected drains, treated sewage effluent, wildlife or overflows without a monitor. A year's count depends on how long the monitor worked, shown as monitor uptime.

Each year, all overflows upstream

Year	Overflows with a return	Spills	Spill hours	Spill hours, weighted by reach
2021	28	1,315	16,305	81
2022	28	448	4,966	16
2023	31	1,669	23,049	93
2024	31	2,605	41,477	239
2025	31	804	11,081	69

Reach is the share of a spill's bacteria SwimSignal's model expects to arrive here, after die-off on the way and dilution by the river. Weighting by it counts an hour of spilling just upstream for far more than one 40 km away. Spills are counted by the Environment Agency's 12/24 method: any discharge in the first 12 hours counts as one spill, then one more for each 24 hours with any discharge. How reach is worked out.

The overflows, by reach

All 31, the one whose spills matter most here first. Hours away is how long sewage takes to arrive at the model's river speed.

Overflow and id	Company	km upstream	Hours away	Reach	Spills 2023	Spills 2024	Spills 2025	Spill hours 2025	Monitor uptime 2025
Goring sewage works overflow Goring STW · TWL00199	Thames Water	9.0	5	62%	0	0	0	0	100%
Dorchester sewage works overflow Dorchester STW · TWL00157	Thames Water	24.5	14	9%	4	63	15	121	100%
Heyford Hill Lane (Littlemore) pumping station overflow Heyford Hill Lane (Littlemore) SPS · TWL00273	Thames Water	49.7	28	1%	5	26	1	6	100%
South Moreton sewage works overflow South Moreton STW · TWL00378	Thames Water	21.5	12	1%	162	261	137	2,721	99%
Cholsey sewage works overflow Cholsey STW · TWL00097	Thames Water	15.8	9	1%	2	45	4	44	99%
Drayton sewage works overflow Drayton STW · TWL00162	Thames Water	39.2	22	1%	116	128	47	639	100%
Beenham sewage works overflow Beenham STW · TWL00031	Thames Water	10.5	6	1%	62	54	14	132	100%
Chapel Row sewage works overflow Chapel Row STW · TWL00081	Thames Water	12.2	7	0%	85	112	21	253	95%
Benson sewage works overflow Benson STW · TWL00034	Thames Water	18.2	10	<1%	12	101	18	361	97%
Didcot sewage works overflow Didcot STW · TWL00155	Thames Water	34.7	19	<1%	61	94	26	339	100%
Hampstead Norreys sewage works overflow Hampstead Norreys STW · TWL00211	Thames Water	20.1	11	<1%	83	55	33	628	100%
Oxford sewage works overflow Oxford STW · TWL00323	Thames Water	49.6	28	<1%	133	162	43	590	100%
Briff Lane (Bucklebury) sewage works overflow Briff Lane (Bucklebury) STW · TWL00061	Thames Water	14.7	8	<1%	85	73	23	221	100%
Little Milton sewage works overflow Little Milton STW · TWL00271	Thames Water	38.7	22	<1%	68	168	64	1,310	98%
Appleton sewage works overflow Appleton STW · TWL00013	Thames Water	51.5	29	<1%	121	160	17	159	100%
Culham sewage works overflow Culham STW · TWL00147	Thames Water	30.0	17	<1%	32	78	38	378	100%
Worminghall sewage works overflow Worminghall STW · TWL00464	Thames Water	53.6	30	<1%	52	93	23	264	100%
Wantage sewage works overflow Wantage STW · TWL00425	Thames Water	52.3	29	<1%	78	96	30	170	100%
Abingdon sewage works overflow Abingdon STW · TWL00004	Thames Water	38.7	22	<1%	38	85	13	112	100%
The willows, north hinksey lane TWL00411	Thames Water	55.0	31	<1%	11	8	7	48	100%
Forest Hill sewage works overflow Forest Hill STW · TWL00188	Thames Water	50.5	28	<1%	3	5	3	4	100%
West way, botley (syphon) TWL00439	Thames Water	55.9	31	<1%	26	18	10	40	96%
Watlington sewage works overflow Watlington STW · TWL00433	Thames Water	45.5	25	<1%	8	90	30	137	100%
Tetsworth sewage works overflow Tetsworth STW · TWL00408	Thames Water	50.2	28	<1%	36	30	6	42	100%
Horton-Cum-Studley sewage works overflow Horton-Cum-Studley STW · TWL00238	Thames Water	54.6	30	<1%	55	76	38	462	99%
Chalgrove sewage works overflow Chalgrove STW · TWL00080	Thames Water	42.2	23	<1%	132	147	8	56	100%
Wheatley sewage works overflow Wheatley STW · TWL00446	Thames Water	44.2	24	<1%	124	160	76	1,125	100%
Shabbington sewage works overflow Shabbington STW · TWL00363	Thames Water	56.3	31	<1%	48	67	23	322	88%
Kingston Bagpuize sewage works overflow Kingston Bagpuize STW · TWL00257	Thames Water	53.9	30	<1%	25	143	32	389	100%
Tubney XX pumping station overflow Tubney SPS XX · TWL00806	Thames Water	51.3	28	<1%	0	7	1	1	100%
Stanford in the Vale sewage works overflow Stanford in the Vale STW · TWL00387	Thames Water	59.7	33	<1%	2	0	3	6	100%

A dash: no annual return for that overflow in that year.

Sources and credits

Storm overflow annual returns: © Environment Agency copyright and/or database right 2025, Open Government Licence v3.0. Overflow positions: the water companies via the National Storm Overflow Hub, CC BY 4.0. River network: contains OS data © Crown copyright and database right 2026 (OS Open Rivers). Traced and weighted by SwimSignal (swimsignal.co.uk), whose method is at swimsignal.co.uk/methods.html. All credits and licences.