Sewage spill around Sidmouth’s beach: what’s it all about?

Ed Dolphin writes this guest piece for the Sid River website – with thanks for the considerable research he has carried out. All of which makes for a very clear and helpful overview of what has been happening these last two years.


The Daily Mail Online made unpleasant reading this morning with Sidmouth highlighted as among the worst five bathing beaches for sewage discharges. Many people will be aware that there is a national campaign on the issue with very prominent coverage by people such as Feargal Sharkey and the Rivers Trust, but the local situation may be a shock to some people. Local volunteers have been working for the last two years challenging South West Water and the Environment Agency over the performance of the Sidmouth system which is clearly inadequate for local needs. Their efforts are beginning to pay off but there is a long way to go.

The Sidmouth group’s work has focussed on challenging SWW and the EA and has not been publicised widely because the town does not need the kind of media attention it is receiving now. The pressure on the water company has started to bring local results and SWW is starting work soon on things that should begin to improve the local system in the next year.

It is unlikely that our small valley would have been catapulted to the head of the queue without the efforts of town councillors and local citizen scientists’ determined collection and analysis of data, and then the presentation of challenging questions to SWW and the EA, the squeaky wheel is getting the oil. To give him his due, local MP Simon Jupp has played his part by opening doors for the questions to hit home and raising the issue himself at various levels of Government.


Sidmouth’s sewage system is inadequate because of insufficient investment over several decades, even before the privatisation of the public service in 1989. The water services were sold off for ideological reasons but also to avoid the public purse having to foot the bill for improvements necessary to meet new standards brought in by what was then the EEC.

Although the new companies did comply with the new drinking water directive, they have never invested enough money in the infrastructure for the treatment of sewage and, up until it has literally hit the fan, nobody was paying attention. Certainly not the two regulatory bodies the EA and Ofwat whose inadequate resources have hampered them in doing an effective job.

The system has deteriorated steadily while increasing population and the advent of new hazards to the system such as non-degradable wet wipes has added pressure to the creaking waste disposal system.

Across the country, to avoid local systems being overwhelmed in heavy rain and the sewers overflowing to flood people’s houses there are escape outfalls called Combined Sewer Overflows. These are passive openings which overflow to a water course if the system is becoming overloaded. Any system should be set up to cope with normal rainfall and the CSOs should only come into use when there is exceptional rainfall. In recent years, the nation’s systems have failed to keep up with the pressures put on them and they are now overflowing far more often than they should.

It is a widely held belief that water privatisation has been bad for us.


In recent media interviews SWW has claimed they are making progress and halved the number of spills from 2021 to 2022. Closer scrutiny reveals that the claim is restricted to spills in the official bathing season, May to September. Sidmouth’s CSO spill count did almost halve between 2021 and 2022, but it was nothing to do with any work by SWW. As you would expect, there is a strong correlation between the amount of rain and the number of spills, the more it rains the more likely the system will overflow. This is not a total link because other factors play a part but approximately 70% of any major change in spill numbers is likely to be accounted for by changes in rainfall.

It turns out that 2021 was a fairly wet summer by local standards but you may remember that 2022 was a scorching summer, the hottest on record and with a 63% reduction in rainfall compared to 2021, and this was true for Devon and Cornwall generally. As SWW had only carried out improvements on small sections of their total network, they should not be claiming credit for the ‘act of God’ of a dry summer.

The claim to have halved the number of spills was restricted to the bathing season, but we cannot verify that because SWW stopped supplying the data that would allow us to check. They stopped releasing the data because they are under investigation by Ofwat and public access to the data might prejudice any criminal proceedings.

SWW has published the statutory data requirement, the total annual figure which is what was picked up by the Daily Mail and other media. SWW may or may not have halved the summer spill total but they had more than 37,000 spills in 2022, a drop of only 11% from the 2021 figure. Nearly all of this will have been down to a record dry year rather than any progress on updating the region’s sewage system.


On the scale of the SWW region, Sidmouth is a small self-contained system, it is our own excrement that is sometimes entering our river and sea. The overall chronic under investment is exacerbated locally because our sewers are challenged by several problems that threaten to combine and overwhelm it.

There are some modern sections where the foul water (from toilets, showers and kitchen sinks) and surface water (rainwater from road drains and building gutters) are separate and the surface water can be let into the river or the sea without affecting the sewage treatment. However, Sidmouth’s system has too many sections which are outdated and the foul and surface water share a pipe under the roads and this puts the sewage system under strain when there is heavy rain.

Our valley is steep sided and, being in the south west of England, receives regular bouts of heavy rain which cascades down the valley’s roads and would flood the town centre if it wasn’t diverted into the drains whether they are newer separate surface water drains or the old combined sewers.

Our treatment system has to defy gravity. Most of the town’s foul water along with any surface water in the combined sewers ends up in a large collection tank under the Ham and then has to be pumped up to the treatment plant at Sidford.

Per capita, we have a disproportionate concentration of commercial caterers including hotels and there has been a problem in the past with the amount of kitchen discharge that contains more oil or fat than domestic waste which, although dispersed by detergent, carries the danger of congealing with all the other inappropriate domestic material such as wet wipes, paper towels and sanitary products to clog the system and so reduce capacity.

The Sidmouth sewer system has seven CSOs. The main ones are around the collecting tank and pumping station under the Ham. Ham 1 and Ham 2 are responsible for the majority of the overflows, 75 in 2020 and 109 in 2021. They discharge out at sea by the yellow marker buoy 500m off Port Royal with the outfall from the water treatment plant. The yellow buoy outfall is supposed to be far enough out to sea to not affect our beaches, but there is some doubt about this. Even if it is true, the discharges will affect sea life and the gulls can often be seen gathered around the buoy feeding. Ham 3 is for very extreme conditions and has not discharged in the last 3 years.

There are four CSOs further up the system which overflow into the river. These overflows will reduce pressure down at the Ham. With their 2020 and 2021 spill data they are, Manstone (overflows into the Woolbrook, 18 and 37 times), Fortescue (18 and 23 times), Temple Street (2 and 5 times), and Vicarage Road (3 times in 2020 and 2021). Discharges into the river will affect the freshwater biodiversity and, when it reaches the river mouth, if the tide is flowing westwards as it does for half of the tidal cycle, it will be carried across the beach, as can be seen in this aerial picture of cliff fall sediment being carried off east beach.

It would be very difficult to build a system that never overflowed and so a licence from the Environment Agency sets out the conditions under which an overflow is permitted. Any overflows outside of the limits is a breach and could incur a fine from the industry regulator Ofwat. The water companies are required to self report the number of overflows each year and how many were in breach of the licence. The EA and Ofwat have not had the resources that would enable them to police this effectively in recent years and so standards have slipped. In a recent meeting with SWW executives, they more or less admitted that their company would only do as much as they were compelled to do by regulator intervention.

Local citizen scientists associated with the Sid Valley Biodiversity Group began a river monitoring scheme with the Westcountry Rivers Trust in 2020 and they became aware of the problem of sewage spills elsewhere and began looking for published local data. It turned out that our local system has been overflowing many more times per year than it should since at least 2016, the earliest year for which we have data. The regulatory regime had done nothing about this and so the local people began asking awkward questions. As more and more data was accessed, the questions became more and more difficult for SWW, the EA and Ofwat to ignore or fob off with generic answers. The campaign gained the support of the Town Council, remember that tourism is our main industry, and the local MP, Simon Jupp.

The local investigation contributed to the national campaign and finally Ofwat and the Government have been forced to take action. SWW has been told to refund £13m to its customers this year through bill reductions. It is not clear where this money will be sourced, hopefully from company dividends and not the already under resourced capital maintenance budget.

The good news for Sidmouth is that the combined efforts of local citizen scientists, the town council and the local MP have forced SWW to prioritise our system. They will be spending up to £1.3m in the next three years. The first task will be to survey the sewers to find areas where leaky pipes are allowing ground water to infiltrate in and add to the load. The worst sewers will be relined. The company will also be checking to see where rainwater is being misdirected from properties into the foul water system and these will be corrected. I have no idea how they will do that, and how we will know if it has worked. If this work does not reduce the number of spills sufficiently, SWW may seek to enlarge the storage tank under the Ham.

Let us hope the improvements have the desired effect and the system will only overflow if we have truly exceptional rain.