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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 2,336 monitored storm overflows. 7 are currently spilling. In the last 30 days the network has discharged a cumulative 106.3 years across 9,608 events on average. The Truth Engine has 452 open flags against them right now.

2,336

Storm overflows

7

Active right now

0

Monitors offline

452

Open flags

2,402

Spills · last 7 days

106.3 years

Cumulative discharge · 30 days

3 days

Avg event length · 30 days

293

Spills · last 24 hours

Spill record· last 12 months · network-wide

21,969

spill events

+70768% vs prior 12m

1,756,546h

cumulative discharge

+11164981% vs prior 12m

6 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 398.8h per monitored overflow in the last 30 days. The national median was 107.8h 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· 7

  1. 01

    Nant Cledlyn

    Cwrtnewydd WwTW Storm Overflow · spilling for 1.1 h

  2. 02

    Henllan Brook

    Llanelwedd Storm Overflow · spilling for 1.1 h

  3. 03

    Nant Aeron

    Heol Y Farchnad Road Storm Overflow · spilling for 5.9 h

  4. 04

    Swansea Bay

    Norton Road and Avenue Junction Swansea Storm Overflow · spilling for 18.4 h

  5. 05

    Afon Twrch

    Bethel Road Cwm-twrch Isaf Overflow · spilling for 21.9 h

  6. 06

    River Dulais

    Crynant WwTW Storm Overflow · spilling for 35.4 h

  7. 07

    River Machno

    Cwm Penmachno WwTW Storm Overflow · spilling for 11 days

Truth Engine flags against Dwr Cymru Welsh Water· 25 open