MPs Warned that Unchecked Road Runoff Pollution is Seriously Threatening England’s Rivers

Carcinogens entering waterways from 25,000 road outflows are not monitored or regulated by Environment Agency, committee hears.

Toxic discharges from thousands of road outfalls are polluting rivers across England but remain largely ignored by both politicians and regulators, MPs have been told.

Giving evidence to the Environmental Audit Committee, experts warned that more than 25,000 highway outfalls release polluted water directly into rivers whenever it rains. This runoff carries harmful particles from tyres and brakes, along with fuel and oil residues, creating a toxic mix that can devastate aquatic ecosystems.

A Major but Overlooked Contributor to River Failure

Road runoff is estimated to account for 18% of the reasons rivers in England fail to achieve good ecological and chemical status. Despite this, unlike sewage discharges from water companies, the pollution is neither monitored nor regulated by the Environment Agency. There is currently not a single permit in place for highway outflows.

“Every Rainfall Brings Toxic Pollution”

Jo Bradley, director of operations at Stormwater Shepherds, described the discharges as “toxic, carcinogenic and containing heavy metals, hydrocarbons and microplastics.” She told MPs that while National Highways has identified 126 outfalls as high-risk and pledged to address them by 2030, all 25,000 discharge points are polluting rivers during rainfall events.

Bradley contrasted the scale of the problem with the attention given to sewage. “While sewage pollution attracts all the coverage – with £56bn earmarked to address it – only a few million is being invested to tackle pollution from 25,000 road outfalls,” she said. “No one is measuring these harms. No one is interested.”

Limited Policy Response So Far

The Cunliffe review of the water sector has done little to address road runoff pollution, the committee heard. Bradley argued that the forthcoming government white paper must recognise the problem and provide a strategy to tackle it.

“Flying Under the Radar”

Catherine Moncrieff, head of policy and engagement at the Chartered Institution of Environmental and Water Management, told MPs that the issue was worsening. “The problem of highway pollution is increasing,” she said. “The issue is getting worse.”

An investigation has mapped the 25,000 sites where road runoff is entering rivers, highlighting the scale of the challenge. Campaigners say action is urgently needed to bring the problem in line with other regulated sources of pollution.

The Environment Agency has said it does not regularly monitor runoff but recognised that runoff from highways and urban areas was a serious issue.

Nick Harris, the chief executive of National Highways, said about 250 high-risk sites that needed mitigation by 2030 had been identified out of 1,236 outfalls that had been checked. He said so far 40 sites had been worked on.

“We should care very much about this pollution going into the environment,” he said. “The commitment we have made is to address the high-risk sites by 2030.”