Dŵr Cymru Welsh Water storm overflows in 2025

How many spills each outlet recorded

Outlets with a usable 2025 count, grouped by the number of spills. The longest bar is the largest group.

0

9 7.4%

1 to 9

39 32%

10 to 19

17 13.9%

20 to 39

32 26.2%

40 to 59

15 12.3%

60 or more

10 8.2%

Spills over time

The median outlet run by Dŵr Cymru Welsh Water recorded 14.5 spills in 2025, against 11 across England.

100 outlets have a comparable count for both 2024 and 2025, with the monitor working at least 90% of each year. 6 recorded more spills, 89 fewer and 5 the same. Together they went from 4,568 to 2,414 spills, a fall of 47%.

Largest rises from 2024 to 2025

• Plough Lane Hereford CSO12 → 40
• Willaston Mill Lane7 → 34
• Wealstone Lane CSO21 → 27

Earlier returns list fewer of these outlets, so totals are not comparable between years. The median per outlet and the like-for-like change are fairer comparisons. Counts are events, not volume.

Largest falls from 2024 to 2025

Only outlets with a count in both years and at least 90% monitor operation in each. Counts depend on rainfall as well as on the sewer network, so a fall does not show on its own that an overflow improved.

• Tarrington120 → 23
• Moccas WwTW115 → 21
• Hereford Eign121 → 47
• Eardisley WwTW108 → 37
• Saighton121 → 53
• Neston125 → 63
• Neston Parkgate145 → 85
• St Briavels WwTW195 → 136
• New Court Lugg Bridge89 → 32
• Aldford CSO107 → 54

Waterbodies with the most spills

Total 2025 spills from outlets the return links to each waterbody. A waterbody with more outlets will usually have a higher total.