Campaigns · · 6 min read
Emergency overflows: the sewage spills nobody is shown
The Dart’s 18 emergency overflows discharged for about 5,171 hours between 2020 and 2025, and none of it appears in the public spill data. Part two of our series on what River Hub can show.
This is the second post in our series on what River Hub can show about the Dart. Part one looked at storm overflows spilling when it hadn’t rained. This time we look at a kind of overflow that doesn’t appear in the public data at all: the emergency overflow.
Between 2020 and 2025, the 18 emergency overflows on the Dart discharged for about 5,171 hours. That is more than 215 days. None of it showed up on South West Water’s WaterFit Live map, and none of it is in the Environment Agency’s annual storm overflow figures. We only know because we asked.
What an emergency overflow is
Much of the Dart’s sewage has to be pumped uphill to reach a treatment works. An emergency overflow is a relief outlet at a pumping station. If the pumps fail, through a power cut, a mechanical fault or a blockage, it lets raw sewage out into the river rather than back up into homes and streets. That is its only permitted use: a genuine emergency, for as short a time as it takes to fix the fault.
Emergency overflows carry the same monitors as storm overflows, recording every start and stop at 2-minute intervals. But their data sits in a different category. It is not in the near-real-time feed that powers WaterFit Live and River Hub’s live board, and it is not in the Environment Agency’s annual storm overflow return. So when one discharges, nobody downstream is told.
In June 2026 we asked South West Water for the records under the Environmental Information Regulations (reference EIR26209). The company replied on 12 August with a list of the 18 emergency overflows in the catchment and their spill data for 2020 to 2025. It also told us two things it does not record: how much sewage each discharge releases, and whether a discharge happened in dry weather or outside emergency conditions.
What the records show
Three overflows account for almost all of it. Warfleet No2 in Dartmouth, and Dart Bridge and Blackrock near Buckfastleigh, discharged for about 4,566 of the 5,171 hours between them. Most of the Dart’s emergency overflows only had monitors fitted in 2022, so the earlier years show little.
Emergency overflow | Monitor fitted | 2022 | 2023 | 2024 | 2025 | Total hours |
|---|---|---|---|---|---|---|
Warfleet No2 pumping station, Dartmouth | 2023 | 0 | 2,514 | 0 | 0 | 2,514 |
Dart Bridge pumping station, Buckfastleigh | 2022 | 186 | 920 | 14 | 19 | 1,140 |
Blackrock pumping station, Buckfast | 2022 | 131 | 375 | 189 | 217 | 913 |
South Town, Dartmouth | 2022 | 55 | 128 | 35 | 7 | 225 |
Nelson Close pumping station, Staverton | 2022 | 18 | 164 | 0 | 0 | 182 |
Warfleet Creek pumping station, Dartmouth | 2016 | 5 | 78 | 2 | 3 | 88 |
Darthaven Marina pumping station, Kingswear | 2022 | 1 | 28 | 22 | 2 | 54 |
11 other emergency overflows | 0 | 18 | 35 | 2 | 56 | |
All 18 | 396 | 4,226 | 298 | 250 | 5,171 |
Hours of discharge each year, rounded. 2020 and 2021 are left out: they add about one hour between them. Source: South West Water, EIR26209, from its emergency overflow annual returns.
An emergency overflow should fire for minutes, a handful of times, when something breaks. Warfleet No2’s 2,514 hours in 2023 is about 105 days of continuous discharge, in the year its monitor was fitted. Dart Bridge’s 920 hours that year is about 38 days. These are not emergencies in any ordinary sense of the word.
Blackrock: a fault, not an emergency
Blackrock pumping station at Buckfast sends sewage on to Kilbury treatment works at Buckfastleigh. Its emergency overflow has discharged heavily in every year since its monitor was fitted:
- 2022: 131 hours
- 2023: 375 hours
- 2024: 189 hours, the most of any emergency overflow on the Dart that year
- 2025: 217 hours, more than in 2024
One bad year could be bad luck. Four years of long, repeated discharges looks like a fault that has not been fixed. Its neighbour, Dart Bridge pumping station, feeds the same works and discharged for 920 hours in 2023. Kilbury also appeared in part one: its storm-tank overflow has spilled in dry weather every year since 2020.
The missing impact assessments
When an emergency overflow discharges, South West Water can file a “No Impact Statement” with the Environment Agency, setting out why it thinks the discharge did no harm. Its response to us included nine of them, covering discharges between February 2020 and December 2025. Every one is for an overflow at the mouth of the estuary in Dartmouth: Mayors Avenue, Warfleet Creek and Dartmouth treatment works. Several describe discharges that lasted a few hours, and some were of treated effluent rather than raw sewage.
There is no statement for Blackrock, Dart Bridge or Warfleet No2, the three overflows that discharged the longest. The company has documented short discharges near the sea, but not the longest-running emergency overflows on the river. South West Water also told us it does not record whether its emergency overflow discharges happen in dry weather, so it cannot say whether any of these were genuine emergencies.
What we have asked the Environment Agency
On 7 October 2026 we wrote to the Environment Agency with these figures and the full dataset, overflow by overflow and year by year. Because the data comes from monitoring the Agency already receives, our questions are about what it knows and what it is doing:
- Is the Agency aware of these discharges, and of the pattern at Blackrock in particular?
- Has anyone, the company or the Agency, ever assessed the impact of Blackrock’s discharges? If short discharges in Dartmouth warranted a No Impact Statement, why hasn’t the river’s longest-running emergency overflow?
- Does the Agency regard repeated discharges of this length as consistent with a permit that allows them only in genuine emergencies?
- Is any investigation or enforcement under way at Blackrock, Dart Bridge or Warfleet No2?
- Are any of these overflows in an improvement scheme, and if so, by when?
- What is the Agency doing to bring these discharges back within their permits?
We asked for any investigation reports, impact assessments and correspondence with South West Water under the Environmental Information Regulations. We’ll report what comes back.
Why River Hub, and why it needs to go national
Emergency overflows show why open data on its own is not enough. The figures exist. They come from monitors the public has paid for, and they are reported to the regulator every year. But because they sit outside the published storm overflow data, nobody outside the company and the Agency looks at them unless a volunteer group thinks to ask.
River Hub now puts them in the open. Its emergency overflows page lists all 18 on the Dart, year by year, next to the live storm overflow data. It is a snapshot rather than a live feed, and we will update it each time we get a new disclosure.
Every water company in England has emergency overflows, and the same gap applies everywhere. If River Hub ran nationally, river groups could request the same records for their own rivers and put them alongside the storm overflow data in a consistent way, instead of each starting from scratch. But the real fix is for the data not to be hidden in the first place. Friends of the Dart will push South West Water, the Environment Agency and the government to publish emergency overflow data alongside storm overflow data, ideally as a live feed on WaterFit Live, so that people know when raw sewage is going into their river.
If you’re part of a river group and would like River Hub for your river, or you’d like to help us build it, please get in touch at hello@friendsofthedart.org.
Coming up in the series
Future posts will look at overflows that spill before their treatment works is full, whether the works can cope with the homes they serve, and which problem overflows have no improvement planned.
