311 days of sewage in six years

The two gaps, and what they actually are

Two years show fewer than seven outfalls reporting, and neither gap is a hidden number. Both Milnhay monitors were installed in 2021, so 2020 has five outfalls simply because the other two were not yet being measured.

2025 is different. The inlet overflow at Milnhay works, on its own responsible for 1,757 hours of discharge since 2021, was decommissioned in January 2025. Severn Trent’s return records it as “no longer operational as an overflow, permit revoked or to be revoked” and “no longer spilling to environment”. That one really is gone, and this page says so, because a page that only reports bad news is not worth reading.

It was part of something bigger. Between 2022 and 2024 Severn Trent spent around £35.8 million rebuilding Newthorpe works, south of Eastwood, and shut Milnhay down as a treatment works altogether. Milnhay is now a pumping station: what it collects is pumped 2.5 km to Newthorpe and treated there. Only the storm tanks were kept here, and their capacity was raised from 2 megalitres to 7.

That scheme was built to meet the Water Framework Directive and, specifically, tighter limits on phosphate that came into force in December 2024. This river was classified Poor in 2016 and has been Poor at every assessment since. The works discharged into it throughout those eight years. What changed was not the state of the Erewash, which was on the record the whole time. What changed was the law.

And it has not fixed it. The storm tank they enlarged discharged for 305 hours in 2025, the first full year after the work was finished. By 1 September 2026 it had already discharged for 266 hours, with four months of the year still to run. It remains the largest single source in the parish, and the live feed above records it discharging into the Erewash within the last few days. Across the parish as a whole the shape is the same: 700 hours in 2025, and 606 so far this year.

So one of the two outfalls at Milnhay has stopped, and the other has not. The decommissioned one no longer appears on Severn Trent’s live map at all, which is the clearest confirmation that it really has gone.

“It was just a wet year”

That is the first thing you will be told, so it is worth checking. Rainfall measured at six Environment Agency gauges around the parish, averaged, against discharge, year by year:

Rain explains some of it: 2023 was the wettest year and one of the worst. But it does not explain most of it. 2021 was drier than 2020 and produced six times as much discharge. The correlation across the six years is 0.52, real but far from the whole story. The rest is what condition the network is in and how much is being asked of it. Severn Trent’s own return names the cause at Milnhay: “hydraulic capacity”. The works cannot take what is being put into it.

Six of the seven outfalls discharge into the River Erewash. The seventh, at Lee Lane, goes into Bailey Brook, which joins the Erewash a little downstream. The Erewash is the county boundary here, and it runs the length of the parish, past the Great Northern Basin at Langley Mill where the Erewash, Cromford and Nottingham canals meet.

This is water people walk their dogs beside, fish in, and moor boats on.

One thing this page does not claim: that the sewage gets into the canal. The pump house at Langley Mill Basin does back-pump, but it lifts water from the Erewash Canal below Langley Bridge Lock up into the basin above it: canal water, recirculated round a lock, not water taken from the river. The basin above is fed from the Nottingham Canal feeder off Moorgreen reservoir. The river and the canal run side by side here and are easy to conflate, which is exactly why it is worth being precise about it. (The pump house itself is a Victorian sewage pumping station that Severn Trent were going to demolish; canal volunteers hold it on a 99-year lease.)

The official assessment

The Environment Agency classifies every stretch of river in England. Our reach, the Erewash from Nethergreen Brook down to Gilt Brook, the water that runs past Langley Mill, is classified Poor.

It was Moderate in 2013, 2014 and 2015. It dropped to Poor in 2016 and has stayed there through every assessment since. Four measures are below good: phosphate and the plant life are Poor, the invertebrates and the dissolved oxygen are Moderate. Invertebrates are the ones that tell you most: they live in the riverbed and cannot swim away from a bad week.

The Agency also records why, pressure by pressure, with a certainty against each. For this stretch it lists twenty reasons. Farming and urban run-off appear, marked Probable. Two are marked Confirmed, the Agency’s highest level, and both are sewage:

“Sewage discharge (intermittent)” is the Agency’s term for a storm overflow. So the regulator has already concluded, and published, that the overflows on this page are one of the confirmed reasons this river is in poor condition. That is not my claim. It is theirs.

One thing to be straight about. The river also fails its chemical status, and has since 2019, but not because of sewage: the substances responsible are PBDEs, PFOS and mercury compounds, which are persistent industrial pollutants found in nearly every river in England. That failure is real and it is not Severn Trent’s. The ecological failure, the one the Agency attributes in part to sewage, is the one this page is about.

Water Framework Directive classification for water body GB104028052511, from the Environment Agency’s Catchment Data Explorer, latest data updated 17 March 2025. Element results are the 2022 assessment. Certainty levels are the Agency’s own: Confirmed, Probable, Suspected.

And what comes out of a bottle

The classification is an assessment. This is measurement. The Environment Agency samples these waters roughly monthly and publishes every result, so the parish’s own brook can be looked at rather than a reach average.

Bailey Brook, sampled at Milnhay Road, a few hundred metres below the Lee Lane outfall, normally carries about 0.10 mg/l of ammonia. That was its average every year from 2015 to 2021. Then:

In 2022 the average was seven times that, with a single sample at 3.50 mg/l. In 2025 it was eight times, peaking at 2.60. And in 2025 the dissolved oxygen in the same brook fell to its lowest in the record.

Ammonia rising while oxygen falls is what sewage does to a watercourse. Ammonia is the sharpest chemical signal of it in freshwater, and the oxygen goes because breaking it down consumes it. That is also the pairing the Environment Agency lists sewage against, above.

These are monthly spot samples, so a peak is a snapshot of one morning rather than a measure of how long anything lasted, and this page does not claim a particular discharge caused a particular reading. What it shows is that the brook running through this parish has twice in four years carried many times its normal ammonia load. Figures are annual means of all results at that point, from the Environment Agency’s Water Quality Archive.

There is a sampling point on the Erewash immediately upstream of Milnhay works, which would let anyone compare the river above and below the works directly. It has recorded nothing since 2015. If you write to the Environment Agency, that is a good question to put to them.

Everything upstream comes through here

The Erewash rises near Kirkby-in-Ashfield and runs about 40 km south to the Trent, forming the Derbyshire and Nottinghamshire border for most of that. Our parish holds 8.3 km of it, and the seven outfalls on the map above are the ones inside that stretch. They are nowhere near all of them.

Severn Trent operate 83 monitored storm overflows in this river’s catchment. Thirty-seven of them are upstream of us: nineteen on the Erewash above us, fourteen on Bailey Brook, four on Nethergreen Brook. Every one of those drains into water that then flows through this parish.

So the river reaching Langley Mill has already taken the discharges of Pinxton, Somercotes, Ironville, Pye Bridge, Jacksdale, Brinsley and Eastwood on the Erewash, and of Codnor, Loscoe and Heanor down Bailey Brook. By the time it gets to us it is carrying more than five times as many outfalls’ worth of sewage as we add to it.

That cuts both ways and both ways are worth saying. We are not only producing this: we are receiving a great deal of it. And what leaves here does not stop at the boundary either: another 40 outfalls discharge into the Erewash below us, and all of it goes to the Trent.

Worked out hydrologically, not by looking at the map. Each outfall carries a Water Framework Directive waterbody reference in the Environment Agency’s return, the Agency’s own division of the river into reaches, and those are placed along the river’s actual course, taken from OpenStreetMap, to give every outfall and every point of our boundary a distance downstream. Upstream means the water enters above the point the river enters the parish, which puts our own Lee Lane outfall in the upstream count: it discharges into Bailey Brook a few metres before the brook reaches us. Counts monitored Severn Trent storm overflows only, so it is a floor: not unmonitored assets, not other companies, not farm or road runoff.

And storm overflows are not the only things discharging

Everything above is about storm overflows, because those are the ones with an Event Duration Monitor on them and therefore a published number of hours. The Environment Agency’s public register of permitted discharges shows what else is licensed to go into the water here. Inside the parish there are nine permitted discharge points across seven permits, and two of them are not in anything counted on this page.

The register still lists a continuous discharge of treated final effluent at Milnhay. That is what a sewage works is for, it is properly permitted, and it is not a spill. It is also very likely out of date, for the reason above: Milnhay stopped being a treatment works in 2024. When the register and the ground disagree, the register does not tell you which is which.

There is also a permitted sewage discharge into the Erewash at the Cornwood Meadows industrial site, roughly a kilometre north of Langley Mill. It is a Severn Trent pumping station, the permit is active, and it discharges to the river. It does not appear in the Environment Agency’s Event Duration Monitoring return for any year from 2021 to 2025. There is no monitor on it, so there is no number for it: not zero, just nobody counting.

The remaining permit is a private septic tank, and it discharges to ground through a soakaway rather than to the river, so it is not part of this.

From the Environment Agency’s public register, “Consented Discharges to Controlled Waters with Conditions”, filtered to the parish boundary by the grid reference of each discharge point. Active permits only. One outfall sits close enough to the boundary that its permitted discharge point falls just outside it while the monitor itself is inside; it is counted as ours throughout, because it discharges into Bailey Brook a few metres before the brook reaches us.