Downstream of Leeds sewage treatment works
EA name: D/S LEEDS STW (also listed as “RIVER LEN DOWNSTREAM LEEDS SEWAGE WORKS”)
Environment Agency sampling point SO-E0000504 · Freshwater - rivers · listed as open (“open” does not mean it is sampled now)
These are samples taken on a date, not live readings of the river. Results reach the Environment Agency's archive days to months after the sample is taken, so the newest here may be weeks or months old. FloodRadar does not grade them.
Where and when
- Last sampled
- 4 Mar 2026, 10:107 months ago · time as the Environment Agency records it (UK clock time; the source gives no time zone). Not sampled since, as far as the archive shows: the Environment Agency was asked up to 30 Sep 2026 and had nothing newer.
- Samples banked
- 7 since 1 Apr 2025 Imported periods: 1 Oct 2023 – 30 Sep 2026. Samples outside them are not shown here.
- Latest sample
- River / running surface water Environmental monitoring statutory (EU directives)
- Where
- National Grid 582381, 153740As published, to the nearest 1 m. Open in a map
- River, by its own name
- Len
- River, by the map
- River LenPlaced on the river its name gives, 318 m from the line.
- Next gauge downstream
- Maidstone On the River Medway · 8.6 km along the river
- Why it was sampled
- Environmental monitoring statutory (EU directives) (7 samples)
Main measurements, river water
Dissolved oxygen
% saturation · code 9901 · %
100.3%
Sampled 4 Mar 2026, 7 months ago · 7 results banked
Every result (7)
| Sampled | Result as published | Reads as |
|---|---|---|
| 4 Mar 2026, 10:10 | 100.3 | 100.3% |
| 17 Feb 2026, 10:45 | 100.6 | 100.6% |
| 8 Jan 2026, 12:57 | 100.6 | 100.6% |
| 5 Dec 2025, 10:19 | 99.3 | 99.3% |
| 18 Nov 2025, 11:41 | 98.8 | 98.8% |
| 17 Oct 2025, 11:57 | 101.8 | 101.8% |
| 1 Apr 2025, 12:30 | 102.7 | 102.7% |
Dissolved oxygen
as O2 · code 9924 · mg/l
11.2 mg/l
Sampled 4 Mar 2026, 7 months ago · 7 results banked
Every result (7)
| Sampled | Result as published | Reads as |
|---|---|---|
| 4 Mar 2026, 10:10 | 11.2 | 11.2 mg/l |
| 17 Feb 2026, 10:45 | 12 | 12 mg/l |
| 8 Jan 2026, 12:57 | 12.3 | 12.3 mg/l |
| 5 Dec 2025, 10:19 | 11.8 | 11.8 mg/l |
| 18 Nov 2025, 11:41 | 11.7 | 11.7 mg/l |
| 17 Oct 2025, 11:57 | 10.7 | 10.7 mg/l |
| 1 Apr 2025, 12:30 | 11 | 11 mg/l |
Water temperature
code 0076 · °C
10.4 °C
Sampled 4 Mar 2026, 7 months ago · 7 results banked
Every result (7)
| Sampled | Result as published | Reads as |
|---|---|---|
| 4 Mar 2026, 10:10 | 10.4 | 10.4 °C |
| 17 Feb 2026, 10:45 | 7.7 | 7.7 °C |
| 8 Jan 2026, 12:57 | 6.8 | 6.8 °C |
| 5 Dec 2025, 10:19 | 7.7 | 7.7 °C |
| 18 Nov 2025, 11:41 | 8 | 8 °C |
| 17 Oct 2025, 11:57 | 13.2 | 13.2 °C |
| 1 Apr 2025, 12:30 | 12.2 | 12.2 °C |
pH
code 0061
8.27
Sampled 4 Mar 2026, 7 months ago · 7 results banked
Every result (7)
| Sampled | Result as published | Reads as |
|---|---|---|
| 4 Mar 2026, 10:10 | 8.27 | 8.27 |
| 17 Feb 2026, 10:45 | 8.24 | 8.24 |
| 8 Jan 2026, 12:57 | 8.17 | 8.17 |
| 5 Dec 2025, 10:19 | 8.06 | 8.06 |
| 18 Nov 2025, 11:41 | 8.23 | 8.23 |
| 17 Oct 2025, 11:57 | 8.59 | 8.59 |
| 1 Apr 2025, 12:30 | 8.22 | 8.22 |
Ammonia
ammoniacal nitrogen as N · code 0111 · mg/l
below 0.03 mg/l (not detected above this)
Sampled 4 Mar 2026, 7 months ago · 6 results banked
Every result (6)
| Sampled | Result as published | Reads as |
|---|---|---|
| 4 Mar 2026, 10:10 | <0.03 | below 0.03 mg/l (not detected above this) |
| 17 Feb 2026, 10:45 | <0.03 | below 0.03 mg/l (not detected above this) |
| 8 Jan 2026, 12:57 | <0.03 | below 0.03 mg/l (not detected above this) |
| 5 Dec 2025, 10:19 | <0.03 | below 0.03 mg/l (not detected above this) |
| 18 Nov 2025, 11:41 | <0.03 | below 0.03 mg/l (not detected above this) |
| 17 Oct 2025, 11:57 | <0.03 | below 0.03 mg/l (not detected above this) |
Nitrate
as nitrogen (N) · code 0117 · mg/l
15 mg/l
Sampled 4 Mar 2026, 7 months ago · 6 results banked
Every result (6)
| Sampled | Result as published | Reads as |
|---|---|---|
| 4 Mar 2026, 10:10 | 15 | 15 mg/l |
| 17 Feb 2026, 10:45 | 13 | 13 mg/l |
| 8 Jan 2026, 12:57 | 7.79 | 7.79 mg/l |
| 5 Dec 2025, 10:19 | 15 | 15 mg/l |
| 18 Nov 2025, 11:41 | 16 | 16 mg/l |
| 17 Oct 2025, 11:57 | 17 | 17 mg/l |
Phosphate
orthophosphate, reactive, as P · code 0180 · mg/l
0.19 mg/l
Sampled 4 Mar 2026, 7 months ago · 6 results banked
Every result (6)
| Sampled | Result as published | Reads as |
|---|---|---|
| 4 Mar 2026, 10:10 | 0.19 | 0.19 mg/l |
| 17 Feb 2026, 10:45 | 0.19 | 0.19 mg/l |
| 8 Jan 2026, 12:57 | 0.1 | 0.1 mg/l |
| 5 Dec 2025, 10:19 | 0.19 | 0.19 mg/l |
| 18 Nov 2025, 11:41 | 0.17 | 0.17 mg/l |
| 17 Oct 2025, 11:57 | 0.18 | 0.18 mg/l |
Conductivity
at 25 °C · code 0077 · µS/cm
733 µS/cm
Sampled 4 Mar 2026, 7 months ago · 7 results banked
Every result (7)
| Sampled | Result as published | Reads as |
|---|---|---|
| 4 Mar 2026, 10:10 | 733 | 733 µS/cm |
| 17 Feb 2026, 10:45 | 703 | 703 µS/cm |
| 8 Jan 2026, 12:57 | 670 | 670 µS/cm |
| 5 Dec 2025, 10:19 | 721 | 721 µS/cm |
| 18 Nov 2025, 11:41 | 754 | 754 µS/cm |
| 17 Oct 2025, 11:57 | 781 | 781 µS/cm |
| 1 Apr 2025, 12:30 | 737 | 737 µS/cm |
Everything measured here
12 determinands, each kept by its code, unit and sample material: results in different units or on different materials are never mixed. A “below” result is under the laboratory's detection limit, not zero.
Show all 12 rows
| Determinand | Material | Results | First – last | Latest result |
|---|---|---|---|---|
| Oxygen, Dissolved, % Saturation 9901 | River water | 7 | Apr 2025 – Mar 2026 | 100.3% 4 Mar 2026 |
| Oxygen, Dissolved as O2 9924 | River water | 7 | Apr 2025 – Mar 2026 | 11.2 mg/l 4 Mar 2026 |
| Temperature of Water 0076 | River water | 7 | Apr 2025 – Mar 2026 | 10.4 °C 4 Mar 2026 |
| pH 0061 | River water | 7 | Apr 2025 – Mar 2026 | 8.27 4 Mar 2026 |
| Ammoniacal Nitrogen as N 0111 | River water | 6 | Oct 2025 – Mar 2026 | below 0.03 mg/l 4 Mar 2026 |
| Nitrate as N 0117 | River water | 6 | Oct 2025 – Mar 2026 | 15 mg/l 4 Mar 2026 |
| Orthophosphate, reactive as P 0180 | River water | 6 | Oct 2025 – Mar 2026 | 0.19 mg/l 4 Mar 2026 |
| Conductivity at 25 C 0077 | River water | 7 | Apr 2025 – Mar 2026 | 733 µS/cm 4 Mar 2026 |
| Alkalinity to pH 4.5 as CaCO3 0162 | River water | 6 | Oct 2025 – Mar 2026 | 220 mg/l 4 Mar 2026 |
| Ammonia un-ionised as N 0119 | River water | 6 | Oct 2025 – Mar 2026 | below 0.00056 mg/l 4 Mar 2026 |
| Nitrite as N 0118 | River water | 6 | Oct 2025 – Mar 2026 | 0.0094 mg/l 4 Mar 2026 |
| Nitrogen, Total Oxidised as N 0116 | River water | 6 | Oct 2025 – Mar 2026 | 15 mg/l 4 Mar 2026 |
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.