A year of accredited citizen science testing reveals the extent of pollution in the Otter.

Yesterday Owl posted an article about Sidmouth’s Paddle Out Protest “standing in solidarity with those people less fortunate than ourselves, like our friends in the Otter Valley where they’re really struggling with pollution in the River Otter.”

As a consequence Owl received copies of recent Otter Valley Association newsletters which contained astonishing revelations on pollution in the Otter obtained from their citizen science initiative which has just completed a full year of testing.

Their 54 accredited volunteer testers performed 288 location tests compared to the 24 location tests conducted by the Environment Agency over the same period. (Consuming 620 sandwiches, 74 cream teas and 82 beers in the process!)

Richard Foord MP is fully involved – David Reed MP where are you? – Owl

Summary

The results show that phosphate levels rise to alarming levels just south of the main Honiton Sewage works, and remain high all the way down the river as more sewage effluent is pumped into the river at subsequent treatment works and pumping stations, only dropping below the Environment Agency’s “Upper Safe Level” below Otterton.

Following a “Freedom of Information” request to South West Water, daily test results were obtained.for E.coli levels. These were taken at a number of locations around the lower river and Nature Reserve, from November 2024 through May 2025. At White Bridge, where the river Otter meets the tidal estuary. the E.coli levels are higher than the generally accepted ‘Safe Swim Level’ on 90% of days during that period, with the average E.coli reading being five times the ‘Safe’ level.

Following the loss of Budleigh’s Blue Flag beach status in 2025 due to high levels of entero-bacteria, South West Water stated publicly that the E.coli levels at Budleigh’s beach ‘COULD BE CAUSED BY BIRDLIFE IN THE NEW OTTER NATURE RESERVE‘ [did Simon Jupp think that one up?].

In fact, the evidence shows that the nature reserve is a recipient of the River Otter’s entero-bacteria pollution, NOT a significant source for increase.

The team continues to work with Richard Foord, MP, and the River Otter Fisheries Association (ROFA) to engage with both South West Water (SWW) and the Environment Agency (EA). Specific requests have been put to the Environment Agency, including:

A review the operation and permit for Honiton STW in light of environmental harm being caused to a river which is already classified as being “at risk due to phosphate”.

That consideration be given to an amendment to the permit for the Feniton STW upgrade which is due in 2030. such that it requires a high-level of phosphate removal, similar to that which has been highly successful at Fluxton.

That EA add a regular sampling point to the Middle Otter section, somewhere just downstream of Honiton STW. Currently EA have no routine visibility of water quality in the middle or lower Otter, until the sampling point at Dotton. – Owl

One full year of Community Monitoring [OVA spring newsletter]

We set up the ORCA campaigning group about 18 months ago with a call for volunteers. Following the recruitment process, these volunteers were all trained, risk assessments were published and the OVA provided relevant insurance for the testers to operate. Since then we have now completed a full year of 24 completed test cycles by 54 accredited testers performing 288 location tests, on 13 sunny days, 11 rainy days, 3 floods … consuming 620 sandwiches, 74 cream teas and 82 beers! Over 2,880 individual tests and observations have been logged. For this, we would like to extend a huge thank you to our amazing team of volunteers.

This testing is the most comprehensive testing performed on the river Otter — to put this in perspective, the Environment Agency carried out just 24 location tests on the River Otter in the same period.

Our results show that phosphate levels rise to alarming levels just south of the main Honiton Sewage works, and remain high all the way down the river as more sewage effluent is pumped into the river at subsequent treatment works and pumping stations, only dropping below the Environment Agency’s “Upper Safe Level” below Otterton.

As well as analysing our own ORCA data, we also review all other river data sets produced by the Environment Agency, South West Water and other conservation groups. Although the Environment Agency only sample at a few spots in the catchment, the one benefit of their data is that we can analyse phosphate levels at Dotton, a few miles south of Newton Poppleford, once per month over the past 15 years.

Using this data set, we can make a number of important observations:

• The general trend from 2010 to 2020 is a very high and gradually increasing phosphorous concentration in the River Otter, where the increase appears to correlate with the local population increase in the catchment
• Phosphorous level at Dotton then drops significantly in March 2020. This drop coincides with some basic phosphate removal work being completed at Honiton, but more importantly it’s the date when a state-of-the-art phosphate-removal scheme went live at Fluxton sewage works. As Dotton is about four miles downstream of Fluxton sewage works, we see the full impact of this local reduction.
• This significant drop demonstrates that Phosphate-reduction projects at sewage works, of the type we are calling for, really do make a material difference to total phosphate levels in the river
• It also indicates that a similar reduction from sewage works in future, particularly at Honiton and Feniton, would likely produce a similar step-change improvement in measured phosphate levels downstream
• Unfortunately, the chart then shows a slow background increase in phosphate levels from 2020 through to 2026, again likely reflecting increased wastewater from population growth
• It’s clear from the chart that NO other factors appear to have impacted phosphate levels at Dotton, in any way that exceeds the background increase in phosphate through population growth. This includes all agriculture regulatory and advisory work by EA, Westcountry Rivers Trust and Devon Wildlife Trust, which have received £millions in investment. Whilst this work has reportedly reduced phosphate levels in the upper reaches of the Otter and in several of the tributaries, it does not appear to have any impact on net phosphate levels in the lower river.
• That certainly does not mean however that this agriculture advisory work has not delivered important ecological benefits. Key focus areas include reducing soil run-off, stopping livestock from dumping their waste directly in the river, and advising on proper storage of farm waste – which reduces the potential for catastrophic fish kills from slurry. All of this work is very important in creating a rich river environment for the benefit of wildlife and people
• The lack of any apparent reduction in agriculture-derived phosphate levels at Dotton though, given its success elsewhere in the catchment and on other neighbouring rivers such as the Axe, provides important evidence that the majority of the phosphate in the lower Otter is sewage derived.

E.coli levels

Our ORCA team have been testing a wide range of indicators of river quality, and based on those samples plus observations of the river ecology, phosphate appears to be the most important element affecting the environmental health of the river. However, given that the primary source of phosphate is sewage works, and the very high levels of untreated sewage discharges dumped into the river Otter, we were also interested to see what the E.coli levels in the river Otter have been.

Following a “Freedom of Information” request to South West Water, we obtained their daily test results for E.coli levels which were taken at a number of locations around the lower river and Nature Reserve, from November 2024 through May 2025. In particular, we focussed on one key location, White Bridge, where the river Otter meets the tidal estuary. The results are shown in the chart below.

As you can see, the E.coli levels are higher than the generally accepted ‘Safe Swim Level’ (dotted red line) on 90% of days during that period, with the average E.coli reading being five times the ‘Safe’ level.

High levels of E.coli come down the River Otter, particularly after even very slight rainfall in the catchment. Sources are livestock agriculture and untreated sewage discharges, of which there were over 8,000 hours in 2025. Whilst not included in the ecological health classification, high concentrations of these entero-bacteria create a hazard for human and animal health.

Following the loss of Budleigh’s Blue Flag beach status in 2025 due to high levels of entero-bacteria, South West Water stated publicly that the E.coli levels at Budleigh’s beach ‘could be caused by birdlife in the new Otter Nature Reserve’.

To see if that could be the case, we analysed the same SWW dataset to compare the E.coli levels at White Bridge (so above the Nature Reserve), with the daily readings at Otter mouth, which carries the River Otter plus outfall from the Nature Reserve tidal lagoon out to the sea, and from there to our beach.

The Otter mouth samples show ALL E.coli peaks coincide with levels coming down the Otter at White Bridge. Therefore, high E.coli readings at Otter Mouth do NOT appear to come from bird life or other factors in the nature reserve.

In fact, the evidence shows that the nature reserve is a recipient of the River Otter’s entero-bacteria pollution, NOT a significant source for increased E.coli.

We were delighted to have been approached recently by Plastic Free Budleigh to help them in a water testing program in Budleigh Bay. They had been contacted by a team called “Bugwatch” led by Dr Jonathan Cox from Aston University and the Microbiology Society. They are looking to test the water quality at Blue Flag beaches for 7 consecutive days over the Easter period.

As you all know, Budleigh lost its blue flag last year! The team were very happy for us to be involved (for which we say thank you !). So, we asked our ORCA water testers if any of them would be interested in helping out. While this is not exactly on the river, it is testing where the river Otter hits the beach. We were delighted when the team responded in the affirmative. So, we undertook 7 continuous days of testing on the beach near the mouth of the river Otter. These data will be part of a published case study which we will share in due course.

We are now looking at how we can add E.coli testing to the river at selected locations alongside our current chemical testing. To do this we need to invest in new testing equipment and the relevant reagents that are used during each test. We will share more of this testing in future issues of “Otter Life” and via Facebook and web

Collaborating with the EA

Our ORCA team continues to work with Richard Foord, MP, and the River Otter Fisheries Association (ROFA) to engage with both South West Water (SWW) and the Environment Agency (EA). Our latest meeting was a positive and engaging meeting with Richard Foord, ROFA and the EA in order to review all of the data sets relating to phosphate attribution data, ie: apportion where the phosphate in the river comes from. This is important as the Environment Agency use this attribution data to ‘inform where action is most needed and support investment decisions aimed at improving water quality’.

OVA/ROFA’s analysis suggests that sewage works remain the primary source of phosphorus in the Lower Otter, and supports the data published by the EA in 2024.

Our requests from the Environment Agency:

1. A further meeting with EA’s technical team to review EA and ORCA detailed data sets with EA staff in relation to the attribution models, and confirm an attribution model which aligns with measured Phosphate data and timeline of known changes to sewage system.

2. We are asking EA to review the operation and permit for Honiton STW in light of environmental harm being caused to a river which is already classified as being `at risk due to phosphate’, plus East Devon District Council’s damning Water Cycle Study and Honiton’s sewage treatment capacity vs demand today and after a planned 980-home increases. These are just some of the many issues currently affecting Honiton STW. We are asking EA to consider placing a requirement for increased treatment capacity and a state-of-the-art Phosphorous removal scheme and permit.

3. To improve the Feniton STW upgrade which is due in 2030. SWW state that the primary objective is Nitrogen removal, rather than Phosphate. During our discussions with EA, it seems that this upgrade will also now include a (new?) minor form of phosphate removal. However, in view of the clear evidence of environmental harm in the river due to high phosphate levels, we are asking that consideration be given to an amendment to the permit, such that it requires a high-level of phosphate removal, similar to that which has been highly successful at Fluxton.

4. Request that EA add a regular sampling point to the Middle Otter section, somewhere just downstream of Honiton STW. Currently EA have no routine visibility of water quality in the middle or lower Otter, until the sampling point at Dotton.