Dartmoor rivers hit hardest by sewage discharges as Exmoor also at risk

National parks in England and Wales, including Dartmoor and Exmoor, encompass some of the most biodiverse and important rivers in the country.

But new research shows they are being failed by government and water regulators and are now under threat.

A new Rivers at Risk report from the Campaign for National Parks, in partnership with The Rivers Trust, reveals that sewer overflows inside Dartmoor spill, on average, for three times as long as outside.

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Inside Dartmoor the average number of hours spilling from a single sewer overflow was 792 hours, compared to 549 hours across all national parks in England and Wales, and 266 hours outside the parks.

In Exmoor National Park it was 370 hours.

Home to abundant wildlife and some of the UK’s most treasured landscapes, national park waterways should be protected to the highest standards, says the Campaign for National Parks, but 68.5 per cent of rivers in Dartmoor and 44.4 per cent in Exmoor fail to meet good ecological status.

Sewage spills, agricultural pollution and toxic chemicals are risking even the country’s most iconic rivers.

Dr Rose O’Neill, chief executive of the Campaign for National Parks, said: “National parks like Dartmoor and Exmoor should set the gold standard for clean and healthy rivers but instead they are being ignored and neglected by government, regulators and water companies. These are rivers loved by millions of people: if we can’t protect the jewels of our waterways, then we are failing the nation.”

Dr O’Neill added: “Government in England and Wales is in the midst of the biggest reform of the water sector in decades: they must not forget places like our National Parks. It’s time to give these waterways the strongest legal protections, the highest standards, and the urgent investment they deserve.”

Tom Usher, chief executive of the Dartmoor Preservation Association, said: “We strongly support the recommendations in the Campaign for National Park’s Rivers at Risk report. Most of Devon’s major rivers rise on Dartmoor and their health is of paramount importance to the national park and the rest of the county. South West Water and the government must do better to guarantee that our rivers, lakes and estuaries are clean for all and abundant with wildlife.”

In 2024, 49,076 hours of sewage were discharged from water industry combined sewage overflows (CSO) into rivers in Dartmoor.

This is the highest figure out of all 13 national parks in England and Wales.

This reflects ageing and poorly maintained sewage infrastructure that is ill-designed and undersized to cope with actual resident and visitor populations.

Many rural communities within the national parks are below the threshold resident population size where more than basic sewage treatment is legally required, meaning that sewage treatment technologies that are standard elsewhere are not legally required inside national parks.

The report highlights six national park rivers at risk including the River Pulham in Exmoor.

Although there is only one water industry combined sewage overflow (CSO) along its length, 3,077 hours of sewage overflow was discharged into the river in 2024.

This is over ten times higher than the average outside national parks.

Local communities are working tirelessly to protect these waterways.

National park authorities play an important role as local planning authorities and are active in a wide range of catchment management and river restoration projects, but when it comes to tackling the biggest pressures, they have little power and are reliant on the water companies and water regulators to act.

Without changes to legislation and legally binding requirements, national park authorities and communities are swimming against the current, argues the Campaign for National Parks.

With the biggest shake-up of water regulation in decades under way in England and Wales following the Independent Water Commission, the Campaign for National Parks is calling for bold action from government ministers:

1 - Prioritise the parks: Make National Parks a top priority in water reforms, with the highest ambitions for our most special rivers and a new mandate requiring new water regulators and water companies to act.

2 - Strengthen the law: Set legally binding targets to clean up rivers, lakes, and streams in national parks, including high status for iconic sites such as the Usk and the Broads. Fix storm overflows in national parks by 2035 and ban toxic chemicals including damaging ‘spot-on’ flea treatments.

3 - Stop the sewage: Upgrade sewage treatment works within national parks so they are fit for purpose, supported by nature-based solutions and strong enforcement.

4 - Cut farm pollution: Tackle agricultural pollution through better regulation and incentives, with targeted action for water through farming schemes in England and Wales.

5 - Power up the national park authorities: Empower, support and fund national park authorities to play an even greater role in water and catchment management.

The main sectors contributing to the failures on Dartmoor are the water industry (55 per cent), agriculture and rural land management (37.5 per cent) and mining and quarrying (17.5 per cent).

Dartmoor is the joint-second national park most impacted by the water industry.

By comparison the average figures for those sectors across all 13 national parks in England and Wales are: the water industry (41 per cent), agriculture and rural land management (48.6 per cent) and mining and quarrying (8.4 per cent).

Note: Percentages may exceed 100 per cent as many rivers are affected by more than one source of pollution.