100 storm overflows are traced upstream of Ironbridge River Station, the Dee’s lowest gauge on the river map: on the Dee itself, on its gauged tributaries, and on smaller streams that join above there.
- 1 reports discharging now
- 94 not discharging
- 5 offline or silent: 5 monitor offline, 0 status unknown, 0 no live feed
Official annual figures for the overflows traced upstream of Ironbridge River Station, each return added up on its own. The Environment Agency’s return, 2025: 3 spills over 17 hours, from the 1 that has a figure. Welsh Water’s own return, 2025: 2,372 spills over 12,707 hours in total, across the 93 that have a figure. 6 of the 100 have no figure for 2025. These are two separate returns, so the figures are given side by side, not added together.
Each overflow is listed in the stretch above the first gauge its water reaches, from the source down, as on the Gauges tab. A stretch of the Dee includes the smaller streams that join it there. Where a stretch or a tributary has more than 4, the 3 discharging now or nearest its gauge are listed, the rest are counted, and every one is in that gauge’s “Upstream of here” list. Show every overflow in every stretch →
Above New Inn River Station, the Dee’s highest gauge1 overflow · 1 discharging now
Between New Inn River Station and Dee Bridge River Station1 overflow
- Llanuwchllyn WwTW Overflow Not discharging
Dwr Cymru Welsh Water · into Afon Twrch · 7.9 km by river above Dee Bridge River Station · 2025: 108 spills, 1,028 h
Between Dee Bridge River Station and Bala GS River Station1 overflow
- Bala WwTW Storm Overflow Not discharging
Dwr Cymru Welsh Water · into River Dee · 410 m by river above Bala GS River Station · 2025: 92 spills, 694 h
Between Bala GS River Station and Corwen River Station3 overflows
- Llandrillo Storm Overflow Not discharging
Dwr Cymru Welsh Water · into Afon Ceidiog · 9.9 km by river above Corwen River Station · 2025: 20 spills, 299 h - Gwydelwern Storm Overflow Not discharging
Dwr Cymru Welsh Water · into Afon Camddwr · 5.3 km by river above Corwen River Station · 2025: 15 spills, 202 h - Cynwyd WwTW Storm Overflow Not discharging
Dwr Cymru Welsh Water · into River Dee · 3.4 km by river above Corwen River Station · 2025: 83 spills, 292 h
Alwen, above Druid River Stationjoins the Dee above Corwen River Station1 overflow
Between Corwen River Station and Manley Hall River Station25 overflows
and 22 more: show all 25 overflows on this stretch → All above Manley Hall River Station, nearest first →
Ceiriog, above Brynkinalt Weir Chirk River Stationjoins the Dee above Manley Hall River Station6 overflows
- Dolywern WwTW Storm Overflow Not discharging
Dwr Cymru Welsh Water · into River Ceiriog · 8.6 km by river above Brynkinalt Weir Chirk River Station · 2025: 2 spills, 1.0 h - Pontfadog WwTW Storm Overflow Not discharging
Dwr Cymru Welsh Water · into River Ceiriog · 6.3 km by river above Brynkinalt Weir Chirk River Station · 2025: 19 spills, 80 h - Chirk Bank PS Not discharging
Dwr Cymru Welsh Water · into River Ceiriog · 170 m by river above Brynkinalt Weir Chirk River Station · 2025: 3 spills, 17 h
and 3 more: show all 6 overflows on this stretch → All above Brynkinalt Weir Chirk River Station, nearest first →
Between Manley Hall River Station and Farndon3 overflows
Clywedog, above Bowling Bank River Stationjoins the Dee above Farndon23 overflows
and 20 more: show all 23 overflows on this stretch → All above Bowling Bank River Station, nearest first →
Between Farndon and Ironbridge River Station6 overflows
- Chester Road Pulford Storm Overflow Not discharging
Dwr Cymru Welsh Water · into Pulford Brook · 7.8 km by river above Ironbridge River Station · 2025: 23 spills, 73 h - Lavister Storm Overflow Not discharging
Dwr Cymru Welsh Water · into Pulford Brook · 7.3 km by river above Ironbridge River Station · 2025: 116 spills, 1,225 h - Lavister WwTW Overflow Not discharging
Dwr Cymru Welsh Water · into Pulford Brook · 7.3 km by river above Ironbridge River Station · 2025: 69 spills, 888 h
and 3 more: show all 6 overflows on this stretch → All above Ironbridge River Station, nearest first →
Alun, and the streams that join itjoins the Dee above Ironbridge River Station30 overflows
- Pandy Overflow Not discharging
Dwr Cymru Welsh Water · into River Alun · 770 m by river above Pont Y Capel River Station · no official annual figure - Gresford WwTW Storm Overflow Not discharging
Dwr Cymru Welsh Water · into River Alyn · 2.9 km by river above Rossett River Station · 2025: 36 spills, 217 h - Rossett Level Crossing Storm Overflow Not discharging
Dwr Cymru Welsh Water · into River Alyn · 300 m by river above Rossett River Station · 2025: 22 spills, 14 h
and 27 more: show all 30 overflows on the Alun and the streams that join it → All above Rossett River Station, nearest first →
Near these gauges, connection not known
Within 3 km of one of the Dee’s gauges in a straight line, but the river map cannot say whether their water reaches it.
- Holt WwTW Overflow Not discharging
Dwr Cymru Welsh Water · into River Dee · 1.0 km from Farndon in a straight line · no mapped watercourse close enough to be sure · no official annual figure - Outside Corwen WwTW Storm Overflow Not discharging
Dwr Cymru Welsh Water · into Unnamed Stream · 1.2 km from Corwen River Station in a straight line · several watercourses close by, nothing to choose between them · 2025: 73 spills, 329 h - Corwen Clawdd Poncefn Storm Overflow Not discharging
Dwr Cymru Welsh Water · into Tributary Of River Dee · 1.3 km from Corwen River Station in a straight line · no mapped watercourse close enough to be sure · 2025: 0 spills, 0 h
2 other overflows within 3 km of these gauges are placed below the Dee’s lowest gauge or on another river, so not listed.
A status is the water company’s own monitor: it says whether an overflow is discharging, never how much or why, and a spill does not by itself explain a change in a river level. A status older than two hours is shown as unknown. Annual figures are the official returns: 12/24-hour spills for England and Wales, overflow events for Scotland (Scottish Water counts differently, so the two cannot be compared). “No data” means the monitor produced no usable data that year, not zero. Overflows are placed on OS Open Rivers (edition 2026-04), which leaves out many small channels: an overflow the map cannot place may still drain here. Contains OS data © Crown copyright and database rights 2026. Sewage in Britain’s rivers →
Live status: © Dŵr Cymru Welsh Water, from its Storm Overflow Map. Annual figures for England: Environment Agency Event Duration Monitoring return, © Environment Agency copyright and/or database right, Open Government Licence v3.0. Annual figures for Wales: Dŵr Cymru Welsh Water’s return to Natural Resources Wales, as compiled by The Rivers Trust, Open Government Licence.
