4,352 Olympic swimming pools’ worth of untreated sewage was discharged in 2020 from just 30 sewage treatment works

Estimated minimum volumes of untreated sewage discharged from 30 sewage treatment works in 2020, by water authority

Thames Water

2,872 Olympic swimming pools’ worth

1 block = 1 olympic swimming pool’s worth of

untreated sewage (2.5m litres)

Mogden sewage works 2,768

United Utilities 488

Yorkshire 435

Southern 223

South West 209

Welsh 55

Northumbrian 49

Wessex 20

Severn Trent 4

Thames Water 2,872 Olympic swimming pools’ worth

Mogden sewage works 2,768

1 block = 1 Olympic swimming pool’s worth (2.5m litres) of untreated sewage

United Utilities 488

Yorkshire 435

Southern 223

South West 209

Wessex 20

Severn Trent 4

Welsh 55

Northumbrian 49

Guardian graphic. Source: Peter Hammond/Windrush Against Sewage Pollution. Effective regulation of untreated sewage discharges needs volumetric and catchment-based monitoring Note: totals may not match due to rounding