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Home › Rivers › River Nadder

River Nadder water levels

Live levels from 2 monitoring stations across Wiltshire, updated every 15 minutes.

2stations
0above typical high

Gauges

Monitoring stations, source to mouth

StationTownLevel nowStatusTrend
TisburyTisbury0.64 mASD 1h agoNormal—
22.6 km by river
WiltonWilton0.10 m 1h agoNormal—

Stations are listed from source to mouth as the water flows, traced on the river map (OS Open Rivers) and the Environment Agency’s own links between its gauges. A distance “by river” is along the river, and is shown only where the map traces the path.

Contains OS data © Crown copyright and database rights 2026.

Gauged tributaries

Streams and rivers with a gauge whose water joins the Nadder above one of its gauges, from the source down. Named streams without a gauge that have a page here are listed at the end.

No gauged tributary joins the Nadder above Wilton on the river map. Streams without a gauge are not counted here.

Where the Nadder goes

Below Wilton, its water next reaches Salisbury Harnham Bridge, a gauge on River Avon, 7.1 km by river downstream.

Tributaries and where they join are traced on the river map (OS Open Rivers, edition 2026-04) and the Environment Agency’s links between its gauges. The map holds distances between gauges, not the junctions themselves, so a junction is placed between two gauges, and no further up than the tributary’s own lowest gauge. Contains OS data © Crown copyright and database rights 2026.

Streams without a gauge

Named streams on the river map that flow into the Nadder and have no gauge of their own. Each has a page with what is known about it: the next gauge downstream, and any storm overflows or water-sampling points placed on it.

Storm overflows upstream

4 storm overflows are traced upstream of Wilton, the Nadder’s lowest gauge on the river map: on the Nadder itself, on its gauged tributaries, and on smaller streams that join above there.

  • 0 report discharging now
  • 4 not discharging
  • 0 offline or silent: 0 monitor offline, 0 status unknown, 0 no live feed

Official figures for 2025, for the overflows traced upstream of Wilton: 202 spills over 2,916 hours in total, across all 4.

Each overflow is listed in the stretch above the first gauge its water reaches, from the source down, as on the Gauges tab. A stretch of the Nadder includes the smaller streams that join it there.

Between Tisbury and Wilton4 overflows
  • Tisbury Combined Sewer Overflow Not discharging
    Wessex Water · into River Nadder Via Sws · 22.3 km by river above Wilton · 2025: 36 spills, 71 h · reaches the river through a sewer, so where it enters is approximate
  • Fovant Water Recycling Centre Not discharging
    Wessex Water · into Fovant Brook · 14.5 km by river above Wilton · 2025: 81 spills, 1,252 h
  • Barford St Martin Pumping Station Not discharging
    Wessex Water · into River Nadder · 5.6 km by river above Wilton · 2025: 4 spills, 42 h
  • Barford St Martin Wrc Not discharging
    Wessex Water · into River Nadder · 5.2 km by river above Wilton · 2025: 81 spills, 1,551 h

A status is the water company’s own monitor: it says whether an overflow is discharging, never how much or why, and a spill does not by itself explain a change in a river level. A status older than two hours is shown as unknown. Annual figures are the official returns: 12/24-hour spills for England and Wales, overflow events for Scotland (Scottish Water counts differently, so the two cannot be compared). “No data” means the monitor produced no usable data that year, not zero. Overflows are placed on OS Open Rivers (edition 2026-04), which leaves out many small channels: an overflow the map cannot place may still drain here. Contains OS data © Crown copyright and database rights 2026. Sewage in Britain’s rivers →

Live status: © Wessex Water storm overflow activity data, licensed under CC BY 4.0. Annual figures for England: Environment Agency Event Duration Monitoring return, © Environment Agency copyright and/or database right, Open Government Licence v3.0.

Water samples

Dated samples taken by the Environment Agency, not live readings. Results are published days to months after the sample is taken, and many points are sampled only a few times a year, or have not been sampled for years.

22 sampling points on the River Nadder and the streams that join it above Wilton, and below it. 7 have a sample from the last 12 months; 9 have any sample banked. Listed from the source down, grouped by the next gauge each one's water reaches.

Above Tisbury River Nadder 12 points, 2 with samples
Sampling pointWatercourse (map)Above the gaugeLast sampleLatest results (river water)
River Sem upstream of Glebe FarmRiver Sem9.7 kmLast sampled 2 Jan 2003, before the imported period
Nadder at Orchard HouseRiver Nadder9.1 km11 Dec 2023 · 2.8 years agoOxygen 98.6%Temp 8.8 °CpH 7.69Ammonia below 0.03 mg/l
Ferne Brook at Brook WaterFerne Brook9.0 kmLast sampled 31 Jan 2004, before the imported period
Ferne Brook at MilkwellFerne Brook8.9 kmLast sampled 23 Jan 2001, before the imported period
River Nadder at Donhead HallRiver Nadder8.7 kmLast sampled 23 Jan 2001, before the imported period
River Nadder at West End MillRiver Nadder8.2 kmLast sampled 16 Jan 2013, before the imported period
River Sem at Billhay BridgeRiver Sem7.5 kmLast sampled 17 Oct 2003, before the imported period
Nadder Donhead LodgeRiver Nadder7.2 kmNo sample published 1 Oct 2023 – 7 Oct 2026
Sem Gutch CommonRiver Sem6.2 kmNo sample published 1 Oct 2023 – 7 Oct 2026
River Nadder at Lower MillRiver Nadder6.1 kmLast sampled 16 Jan 2013, before the imported period
Sem WardourRiver Sem4.5 kmNo sample published 1 Oct 2023 – 7 Oct 2026
River Nadder at WardourRiver Nadder4.1 km15 Sep 2026 · 23 days agoOxygen 95.2%Temp 15.1 °CpH 8.26Ammonia below 0.03 mg/l
Above Wilton River Nadder 9 points, 6 with samples
Sampling pointWatercourse (map)Above the gaugeLast sampleLatest results (river water)
Nadder TisburyRiver Nadder22 km4 Mar 2024 · 2.6 years agoOxygen 95.3%Temp 7.2 °CpH 7.94Ammonia 0.043 mg/l
Swallowcliffe Stream upstream of Railwayunnamed stream22 km11 Aug 2026 · 58 days agoOxygen 93.5%Temp 15.5 °CpH 8.17Ammonia below 0.03 mg/l
River Nadder at Upper ChicksgroveRiver Nadder20 km2 Jul 2026 · 3 months agoOxygen 99.6% Mar 2024Temp 8.5 °C Mar 2024pH 8.2Ammonia below 0.03 mg/l Mar 2024
Chilmark Stream upstream confluenceunnamed stream17 kmLast sampled 1 Dec 2011, before the imported period
Fovant Brook downstream of Fovant Fish FarmFovant Brook15 kmLast sampled 6 Nov 2017, before the imported period
Teffont Stream at Teffont ManorTeffont Stream15 kmLast sampled 15 Nov 2017, before the imported period
Nadder at Fovant - Catherine Ford BridgeRiver Nadder13 km2 Jul 2026 · 3 months agoOxygen 110.1%Temp 17.3 °CpH 8.29Ammonia below 0.03 mg/l
River Nadder at Burcombe Road BridgeRiver Nadder3.4 km1 Sep 2026 · 37 days agoOxygen 100.9%Temp 15.7 °CpH 8.12Ammonia below 0.03 mg/l
River Nadder at WiltonRiver Nadder0.2 km15 Sep 2026 · 23 days agoOxygen 90.8%Temp 16.1 °CpH 8.06Ammonia below 0.03 mg/l
Below Wilton 1 point
Sampling pointWatercourse (map)Below the gaugeLast sampleLatest results (river water)
Nadder, BemertonRiver Nadder2.3 km22 May 2026 · 5 months agoOxygen 113.6%Temp 15.1 °CpH 8.23Ammonia below 0.03 mg/l

Distances are along the river to the gauge named. England's samples only.

FloodRadar does not grade these results: there is no overall score, and official river classifications are a separate dataset. A sample taken downstream of an overflow does not by itself show where anything in it came from. River connections and distances are traced on OS Open Rivers (edition 2026-04), which leaves out many small channels.

Water samples: Environment Agency Water Quality Archive, © Environment Agency and/or database right 2026, Open Government Licence v3.0.

Contains OS data © Crown copyright and database rights 2026.

Wave tracker for this river → Wiltshire rivers → All UK rivers