Middle Marwood WwTW

Storm overflow run by South West Water, discharging into Knowle Wter & Mid Marwood Strm.

Storm tank at sewage treatment works North Devon constituency
Right now
No live feed
South West Water does not publish a live status for this overflow; only the annual figures below are available.

"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.

2025 official
38spills
744 h · −62% on 2024
Rank in South West Water
#455
of 1,357 overflows by 2025 spills (1 = most)
Monitor in 2025
100% working
Long-term average 91.3 spills a year

Year by year

The Environment Agency's official annual returns, counted the EA's way (12/24-hour spills).

2021
92 spills · 2,031 hmonitor 100%
2022
44 spills · 749 hmonitor 100%
2023
120 spills · 2,637 hmonitor 100%
2024
101 spills · 2,284 hmonitor 98.1%
2025
38 spills · 744 hmonitor 100%

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

South West Water runs another overflow within 300 m that also discharges into Knowle Wter & Mid Marwood Strm. They share the sewer and the storm, so one outlet's figures are only part of what reaches the water.

10m Middle Marwood WwTWSBB00769 —no 2025 figure

This overflow (MIDDLE MARWOOD STW_SSO_MARWOOD): 38 spills in 2025. Distances are between the published outlet points. The names in brackets are South West Water's own, from its return.

What the 2025 return says

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

High-spill review
Performance - SW Infiltration
Investigation
Env Act (SODRP) investigation ongoing, UWWTR investigation completed
Improvement work
No improvement action in reporting period
Monitored since
2018
Water body
Knowl Water

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

We hold no discharge periods for this overflow: it has no live feed, and South West Water has published no event-level log for it that we hold. The official annual figure above is the record to rely on.

Rain nearby last 30 days

Nearest live rain gauge: Rainfall gauge nr Ilfracombe, 6.9 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
Plaistow Mill (Bradiford Water) · 3.4 km
Nearest rain gauge
Council area
North Devon District
South West Water's own name for it
MIDDLE MARWOOD STW_SSO_MARWOOD
Site reference
SBB00770 · permit 203312
Coordinates
51.11692, -4.09725

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 North Devon 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.

Annual spill figures: Environment Agency Event Duration Monitoring return, © Environment Agency copyright and/or database right, Open Government Licence (OGL) v3.0. 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.