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Water company · Wales

Currently spilling

Dwr Cymru Welsh Water

Welsh Water — serves 3 million people across most of Wales and parts of Herefordshire. Major rivers: Wye, Usk, Tawe, Teifi, Conwy. Regulated by Natural Resources Wales rather than the Environment Agency.

Dwr Cymru Welsh Water operates 2,359 monitored storm overflows. 23 are currently spilling. In the last 30 days the network has discharged a cumulative 1.4 years across 12,740 events on average. The Truth Engine has 40 open flags against them right now.

📍 View on national map →📄 Download Truth Report (PDF)⬇ Overflows · CSV

2,359

Storm overflows

23

Active right now

0

Monitors offline

40

Open flags

3,185

Spills · last 7 days

1.4 years

Cumulative discharge · 30 days

59 min

Avg event length · 30 days

352

Spills · last 24 hours

Spill record· last 12 months · network-wide

40,659

spill events

39,148h

cumulative discharge

13 weeks

longest single event (all time)

2025-05-09

first event on record

Across 10 water companies in the EA dataset, Dwr Cymru Welsh Water averaged 5.3h per monitored overflow in the last 30 days. The national median was 2.4h per overflow. ranked 10 of 10 of UK water companies by 30-day spill hours per monitored overflow.

Most-discharged-into watercourses

The 12 watercourses with the most Dwr Cymru Welsh Water overflows discharging into them.

Currently spilling· 23

  1. 01

    River Mellte

    Pontneddfechan WwTW Storm Overflow · spilling for 1.1 h

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  2. 02

    Afon Iaen

    Llanbrynmair Tafolwern WwTW Storm Overflow · spilling for 1.1 h

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  3. 03

    Nant Cledlyn

    Cwrtnewydd WwTW Storm Overflow · spilling for 1.3 h

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  4. 04

    Afon Camnant

    Hirwaun Industrial Estate WwTW Storm Overflow · spilling for 1.6 h

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  5. 05

    Afon y Bala

    Llanberis WwTW Storm Overflow · spilling for 1.7 h

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  6. 06

    River Llynfi

    Talbot Street Maesteg Storm Overflow · spilling for 1.8 h

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  7. 07

    River Mawddach

    Llanelltyd Storm Overflow · spilling for 6 h

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  8. 08

    River Gwili

    Cwmgwili WwTW Storm Overflow · spilling for 25.3 h

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  9. 09

    River Garw

    Llangeinor Bettws Street Storm Overflow · spilling for 28.6 h

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  10. 10

    Ogwr Fawr

    Cemetery Road Ogmore Vale Storm Overflow · spilling for 29.8 h

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  11. 11

    River Gwili

    Crosshands WwTW Storm Overflow · spilling for 37.9 h

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  12. 12

    Afon Irfon

    Llanwrtyd Wells Storm Overflow · spilling for 39.6 h

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  13. 13

    Afon Lledr

    Dolwyddelan WwTW Storm Overflow · spilling for 43.9 h

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  14. 14

    unnamed ditch

    Cwm Penmachno Storm Overflow · spilling for 44.1 h

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  15. 15

    Afon Gwyrfai

    Waunfawr WwTW Storm Overflow · spilling for 44.1 h

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  16. 16

    Nant Brisgyll

    Llan Ffestiniog WwTW Settled Storm Overflow · spilling for 44.8 h

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  17. 17

    Afon Goedol

    Blaenau Ffestiniog WwTW Point 1 Storm Overflow · spilling for 45.1 h

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  18. 18

    Nant Brisgyll

    Llan Ffestiniog WwTW Inlet Storm Overflow · spilling for 45.9 h

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  19. 19

    Hazelbeach Stream

    Waterston WwTW Storm Overflow · spilling for 2 days

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  20. 20

    River Glaslyn

    Beddgelert WwTW Storm Overflow · spilling for 2 days

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  21. 21

    River Ebbw

    Maple Avenue Storm Overflow · spilling for 2 days

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  22. 22

    River Twymyn

    Commins Coch Storm Overflow · spilling for 4 days

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  23. 23

    River Machno

    Cwm Penmachno WwTW Storm Overflow · spilling for 6 days

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Truth Engine flags against Dwr Cymru Welsh Water· 25 open