London Sewers Stink as Drought Stalls Waste Decomposition
Get the Energy newsletter
Daily energy & climate — solar, EVs, oil, the policy fights and tech bets shaping the transition. Free.
- London's sewers have been emitting a foul stench for weeks during the hot, dry summer of 2026, drawing comparisons to the Great Stink of 1858.
- Prof Barbara Evans of Leeds University likened the sewer network to a "giant intestine," saying drought conditions mean microbiological decomposition is happening in the pipes rather than at treatment works.
- Prof Simon Clarke of the University of Reading explained that warmer temperatures accelerate bacterial decomposition, releasing a cocktail of methane, hydrogen sulphide, and nitrous oxide that produces the rotten-egg smell.
- Simon Birkett, founder of Clean Air in London, said the "toxic stench" is especially noticeable near stormwater drains and predicted the public "are not going to forget the summer of 2026."
- Evans said the smell is currently a public wellbeing issue rather than a health risk, though she noted methane buildup in the sewers poses a tiny flammability risk.
- Evans recommended separating "grey water" from sinks and baths from toilet "black water" — a system being introduced in Sweden and Germany — to prevent stench in dry periods.
- London's drainage system still relies on Victorian engineer Joseph Bazalgette's 1858 design, which Evans said needs rebuilding to cope with "both hotter and drier periods and wetter periods."
Why it matters: London's drainage network, built after the original 1858 Great Stink, is now failing in both directions — stinking during droughts and spilling raw sewage during heavy rain — and experts say the Victorian-era system cannot be patched for a climate of extremes. Evans wants a national conversation about separating grey water from black water, an approach already adopted in Sweden and Germany, before the system's limits produce more than unpleasant odors.
Ask SkimNews
