Bowerhill Wastewater Treatment Work

Storm overflow run by Wessex Water, discharging into Berryfield Stream.

Storm tank at sewage treatment works Melksham and Devizes constituency
Right now
Not discharging
Last discharge ended on (21 hours ago).
Times are UK time. Company feed updated 1 min ago

"Not discharging" means the company's monitor reports no discharge right now — not that the water is clean. The feed publishes status only; no discharge volume is measured.

2026 so far
33spills
at least 494 h discharging on 31 days · counted by us, not yet official · 4 discharges whose end the feed did not report (counted, no hours)
2025 official
33spills
373 h · −50% on 2024
Rank in Wessex Water
#256
of 1,285 overflows by 2025 spills (1 = most)
Monitor in 2025
100% working
Long-term average 41.3 spills a year

Year by year

The Environment Agency's official annual returns, counted the EA's way (12/24-hour spills). 2026 is our own running count, the same way, from Wessex Water's monitor log and the live feed. The feed reports only each overflow's latest discharge, so a discharge it moved past before we saw it end is counted as one spill with no hours: the hours are a floor. The official figure is published next spring.

2024
66 spills · 853 hmonitor 100%
2025
33 spills · 373 hmonitor 100%
2026so far
33 spills · at least 494 h

A spill is the EA's 12/24-hour count: the first 12 hours of a discharge count as one, each further 24 hours with discharge as one more. "Monitor" is the share of that year the monitor was working, so a 0 beside a working monitor is a real zero; "no data" means the monitor produced no usable data that year — not zero. Years before 2024 are matched to this site by name and location, because the EA's site IDs changed that year; a monitor figure beside one of them means the outlet's permit confirms the match.

Twin outlet

Wessex Water runs another overflow within 300 m that also discharges into Berryfield Stream. They share the sewer and the storm, so one outlet's figures are only part of what reaches the water.

0m Bowerhill Wastewater Treatment WorkWXW00159Bowerhill Shails Lane Inlet 12spills in 2025

This overflow (Bowerhill Shails Lane Storm Tank): 33 spills in 2025. Distances are between the published outlet points. The names in brackets are Wessex Water's own, from its return.

What the 2025 return says

From Wessex Water's annual return to the Environment Agency for this overflow.

High-spill review
Not Applicable - Ongoing investigation
Long-term review
Performance - GW inundation
Investigation
No investigation activity in reporting period
Improvement work
No improvement action in reporting period
Monitored since
2019
Water body
Avon (Brist) conf R Marden to conf Semington Bk

This overflow spilled often enough to trigger the EA's high-spill review; the review line is the company's own stated reason.

Discharges we have recorded

45 discharge periods since 5 Jan 2025, 4 whose end the feed never gave. 39 of them come from Wessex Water's own event-duration-monitoring records (published on Stream, Jan 2025 – Jun 2026); the live feed adds anything after that. The official annual count is the figure to quote.

Show 30 earlier (of 45)
StartedEndedDischarge time
11 h 16 min
4 d 10 h
2 d 2 h
3 h 8 min
1 d 0 h
1 d 4 h
1 d 23 h
1 d 1 h
3 d 15 h
2 d 7 h
1 d 3 h
1 d 12 h
1 d 0 h
17 h 6 min
3 h 4 min
1 h 26 min
4 h 8 min
19 h 40 min
5 h 38 min
1 d 16 h
5 h 32 min
2 h 34 min
5 h 44 min
1 h 0 min
20 min
2 h 32 min
1 d 2 h
23 h 16 min
13 h 20 min
3 h 28 min

The year figures above use the EA's 12/24-hour counting method, so they are comparable with the official figures; the monitor log's 94 raw blocks were merged into 45 continuous discharge periods (gaps under 15 min joined).

What the feed showed

FloodRadar's own record of every change of state Wessex Water's live feed has shown for this overflow, kept since : 8 states. The feed publishes its status now and its latest discharge, nothing older; the discharges above are read from this. It is here so the figures can be checked.

Show the last 8 states
SeenStatusSinceLatest discharge
Not discharging →
Discharging → no end yet
Discharging → no end yet
Discharging → no end yet
Discharging → no end yet
Discharging → no end yet
Not discharging →
Discharging → no end yet

Rain nearby last 30 days

Nearest live rain gauge: Rainfall gauge nr Melksham, 0.1 km away. Brown shading = when this overflow was discharging; ▼ = a discharge start.

Overflow shading is a timing match, not proof of cause — heavy rain and spills share a trigger. Times come from the water company’s event-duration monitor (site status only; no discharge volume is published).

Where it is

Nearest river gauge
Semington (Semington Brook) · 1.9 km
Nearest rain gauge
Council area
Wiltshire
Wessex Water's own name for it
Bowerhill Shails Lane Storm Tank
Site reference
WXW00160 · permit 102735
Coordinates
51.36025, -2.14057

Tell me when this overflow discharges

One message when the company's monitor reports a new discharge here. At most one every 6 hours.

Setting this alert needs JavaScript. The alerts you already have are on your alerts page.

The alert repeats the monitor's status: whether the overflow is discharging, not how much or why. It can only tell you about a discharge that starts after you turn it on.

Concerned about this overflow?

Report pollution you can see or smell to the regulator straight away; the company handles complaints about the overflow itself.

Write to the MP

The Environment Agency's return places this overflow in the Melksham and Devizes constituency. An MP can ask the company and the regulator questions on a constituent's behalf. These words carry the official figures; change them as you like.

The link opens Parliament's own "Find your MP", which gives the MP's name and how to write to them. FloodRadar sends nothing and keeps nothing you write. Check the constituency against your own address: an MP acts only for people who live in it.

Live status: © Wessex Water storm overflow activity data, licensed under CC BY 4.0. Annual spill figures: Environment Agency Event Duration Monitoring return, © Environment Agency copyright and/or database right, Open Government Licence (OGL) v3.0. Storm-overflow spill events: © the respective water company, published on Stream (data.streamwaterdata.co.uk) under CC BY 4.0. Discharges marked "via Top of the Poops", come from Top of the Poops' record of the same company feed, used under CC BY-SA 4.0: the feed's own start and end times as its pages print them, not their derived hours. Times are shown in UK local time. FloodRadar republishes the monitor's status and the EA's figures; it does not measure discharges itself. Constituency and council area from the EA's return: contains OS data © Crown copyright and database right 2026.