The Scottish Government has been told to better monitor sewage after it was revealed the country is lagging significantly behind England and Wales in reporting storm overflows.

The Marine Conservation Society has called for action from SNP and Greens ministers after the charity recorded more than 35,000 pieces of sewage-related litter on Scottish beaches in 2022.

The UK’s leading ocean charity has found that only 3.4% of storm overflows are monitored and reported on in Scotland, compared to 96% in Wales and 91% in England.

Sepa, which monitors storm overflows, has acknowledged that much of Scotland’s infrastructure is “a legacy from the Victorian era”, adding that “huge national undertaking” will be needed to upgrade it across the UK.

The greatest number of sewage-related items found on the charity’s beach cleans in 2022 were in the Lothians, with 19,590 sewage-related litter items collected and recorded across the year.

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The most sewage-related items found in a 100-metre stretch were in central Scotland, with an average of 358 per 100 metres.

The charity's volunteers in the mid-Scotland and Fife region found an average of 36 sewage-related items in 2022.

Research by the Marine Conservation Society shows that sewage is frequently poured into oceans and seas, even near protected areas and bathing waters, interfering with the ocean’s delicate balance and polluting our shores.

Catherine Gemmell, Scotland conservation officer at the Marine Conservation Society, said, “Monitoring of storm overflows is crucial to improving the sewage situation in Scotland.

“Without data on the problem, the Scottish Government cannot hold those responsible accountable, and we cannot see where the worst affected areas are.”

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She added: “For the sake of wildlife, people and planet, we need investment in monitoring.

“Given how many sewage-related items our volunteers across Scotland find on our beaches, we know the situation is bad, but we need to understand the full extent of the issue, so it can be fixed.”

The Marine Conservation Society is demanding that the Scottish Government reduces the harmful impacts of storm overflow discharges by ensuring that all storm overflows are monitored and reported on by 2026, including frequency, duration, and ecological impact.

Ministers have also been urged to Set progressive reduction targets for sewage spills and ensure that storm overflows only operate during heavy rainfall.

The Government has been told to tackle sewage-related litter in the environment by screening storm overflows, supporting the use of reusable sanitary products and phasing out single-use plastic sanitary products.

Research has revealed that the Lothians has the fewest storm overflows monitored with only four (1.4%) of 296.

Read more: Calls for sewage monitoring as river branded a health hazard

The greatest level of storm overflows monitoring is in central Scotland, but in this area only 29 (7%) of the region’s 422 are monitored.

Despite Scottish Water publishing its improving urban waters routemap in December 2021, with an annual update in 2022 setting out actions being taken to reduce pollution from storm overflows, just 3% across Scotland have been identified as high-priority discharges for improvement by 2027.

Scottish Liberal Democrat leader, Alex Cole-Hamilton, said: "Monitoring is absolutely key, but the Scottish Government just don't seem to get that.

"Right now, they are doing next to nothing to understand the true scale of the sewage problem, undermining any attempts to fix it.  

"This new data emphasises that local communities are yet again bearing the brunt of this shameful SNP/Green inaction."  

He added: "The Scottish-Government owned water company must record and publish all sewage discharges so that we finally have an accurate picture.

"Scottish Liberal Democrats want to see accelerated measures to upgrade our Victorian sewage system and prevent sewage from flowing into our rivers and beaches."

Nathan Critchlow-Watton, head of water and planning at Sepa, said: “Scotland’s water quality is at its highest level ever, with 87% of our water environment rated as good or better. This year, Scotland also has a record-breaking number of bathing waters rated as ‘excellent’.

“We welcome the increased public interest in the environment we all share, and the growing aspiration – heard loud and clear – for our water environment. The river basin management plan sets a water quality target for 92% of the water environment to be in good or better condition by 2027.“

He added: “In many parts of Scotland our wastewater infrastructure, like other areas in the UK, is a legacy from the Victorian era. Recognising the huge national undertaking that will be required to upgrade it means focussing effort where it will have the biggest impact for the environment and communities.

“We’re clear in our regulatory role in ensuring Scottish Water delivers against the urban waters route map, prioritising investment where it will most benefit our environment and communities.

“Scottish Water has committed to installing monitors on every CSO discharging to a bathing or shellfish water by the end of 2024, with near real-time monitoring published for all these monitored CSOs by the end 2024. SEPA will ensure this commitment is delivered.”

A Scottish Government spokesperson said: “Comprehensive monitoring of our water environment is already undertaken by SEPA to assess water quality, water quantity (flows and levels), physical condition and ecology which are combined to produce an overall classification. The results of those assessments are high and we continue to strive for further improvement.

“Increasing the monitoring of sewage outflow pipes would not change the classification of the water environment by SEPA. 66% of Scotland’s water environment as a whole is assessed as having ‘good’ status. 87% of Scotland’s entire water environment is assessed by SEPA as having a ‘high’ or ‘good’ classification for water quality, up from 82% six years ago. 99% of Scottish coastal waterbodies are currently assessed as being in good or better overall condition. It is also important to stress that discharges are not always sewage, but rain water.

“Scottish Water’s improving urban waters routemap, which supports the national river basin management plan objectives (92% good water quality by 2027), commits further investment of up to £500m.

“That investment will improve water quality; increase monitoring coverage at overflow locations which discharge into the highest priority waters; significantly reduce sewage-related debris (SRD) such as wet wipes, sanitary products and other items; and reduce sewer network spills.

“Scottish Water remains on track to deliver on its commitment set out in the routemap to install at least 1,000 new monitors on the network by the end of 2024.”