River Hiz Road Bridge Biggin Lane Hitchin
EA name: R.HIZ RD.BR. BIGGIN LANE HITCHIN
Environment Agency sampling point AN-13M30 · 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
- 3 Sep 2026, 10:5928 days ago · time as the Environment Agency records it (UK clock time; the source gives no time zone)
- Samples banked
- 26 since 16 Oct 2023 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 518532, 229015As published, to the nearest 1 m. Open in a map
- River, by its own name
- Hiz
- River, by the map
- River HizPlaced on the river its name gives, 1 m from the line.
- Next gauge downstream
- Arlesey On the River Hiz · 11 km along the riverARLESEY GS 11 km along the river
- Why it was sampled
- Monitoring (national agency policy) (20 samples)
Environmental monitoring statutory (EU directives) (6 samples)
Main measurements, river water
Dissolved oxygen
% saturation · code 9901 · %
87.7%
Sampled 3 Sep 2026, 28 days ago · 26 results banked
Every result (26)
| Sampled | Result as published | Reads as |
|---|---|---|
| 3 Sep 2026, 10:59 | 87.7 | 87.7% |
| 10 Aug 2026, 10:50 | 93.4 | 93.4% |
| 8 Jul 2026, 11:09 | 91.8 | 91.8% |
| 4 Jun 2026, 11:09 | 91.4 | 91.4% |
| 7 May 2026, 08:08 | 87.4 | 87.4% |
| 13 Apr 2026, 14:03 | 104.6 | 104.6% |
| 4 Mar 2026, 10:41 | 97.7 | 97.7% |
| 10 Feb 2026, 08:12 | 88.4 | 88.4% |
| 14 Jan 2026, 07:55 | 84.9 | 84.9% |
| 18 Mar 2025, 10:04 | 101.6 | 101.6% |
| 6 Feb 2025, 09:33 | 95.3 | 95.3% |
| 22 Jan 2025, 07:32 | 93.7 | 93.7% |
| 2 Dec 2024, 09:00 | 84.7 | 84.7% |
| 18 Nov 2024, 09:18 | 84.8 | 84.8% |
| 17 Oct 2024, 09:18 | 87.1 | 87.1% |
| 16 Sep 2024, 11:17 | 90.2 | 90.2% |
| 19 Aug 2024, 13:07 | 104 | 104% |
| 17 Jul 2024, 10:36 | 94.5 | 94.5% |
| 17 May 2024, 11:58 | 106 | 106% |
| 17 Apr 2024, 08:24 | 93.3 | 93.3% |
| 18 Mar 2024, 08:40 | 95.1 | 95.1% |
| 21 Feb 2024, 11:23 | 79.6 | 79.6% |
| 16 Jan 2024, 08:59 | 91.6 | 91.6% |
| 8 Dec 2023, 16:00 | 75.2 | 75.2% |
| 22 Nov 2023, 08:36 | 66.3 | 66.3% |
| 16 Oct 2023, 08:45 | 83.4 | 83.4% |
Dissolved oxygen
as O2 · code 9924 · mg/l
8.65 mg/l
Sampled 3 Sep 2026, 28 days ago · 26 results banked
Every result (26)
| Sampled | Result as published | Reads as |
|---|---|---|
| 3 Sep 2026, 10:59 | 8.65 | 8.65 mg/l |
| 10 Aug 2026, 10:50 | 9.25 | 9.25 mg/l |
| 8 Jul 2026, 11:09 | 8.72 | 8.72 mg/l |
| 4 Jun 2026, 11:09 | 9.48 | 9.48 mg/l |
| 7 May 2026, 08:08 | 9.75 | 9.75 mg/l |
| 13 Apr 2026, 14:03 | 11.5 | 11.5 mg/l |
| 4 Mar 2026, 10:41 | 11.4 | 11.4 mg/l |
| 10 Feb 2026, 08:12 | 10.4 | 10.4 mg/l |
| 14 Jan 2026, 07:55 | 10.9 | 10.9 mg/l |
| 18 Mar 2025, 10:04 | 12.3 | 12.3 mg/l |
| 6 Feb 2025, 09:33 | 11.9 | 11.9 mg/l |
| 22 Jan 2025, 07:32 | 11.4 | 11.4 mg/l |
| 2 Dec 2024, 09:00 | 9.7 | 9.7 mg/l |
| 18 Nov 2024, 09:18 | 9.86 | 9.86 mg/l |
| 17 Oct 2024, 09:18 | 9.22 | 9.22 mg/l |
| 16 Sep 2024, 11:17 | 9.55 | 9.55 mg/l |
| 19 Aug 2024, 13:07 | 10.6 | 10.6 mg/l |
| 17 Jul 2024, 10:36 | 9.67 | 9.67 mg/l |
| 17 May 2024, 11:58 | 11 | 11 mg/l |
| 17 Apr 2024, 08:24 | 10.9 | 10.9 mg/l |
| 18 Mar 2024, 08:40 | 10.8 | 10.8 mg/l |
| 21 Feb 2024, 11:23 | 8.97 | 8.97 mg/l |
| 16 Jan 2024, 08:59 | 12.1 | 12.1 mg/l |
| 8 Dec 2023, 16:00 | 9.05 | 9.05 mg/l |
| 22 Nov 2023, 08:36 | 7.84 | 7.84 mg/l |
| 16 Oct 2023, 08:45 | 10.1 | 10.1 mg/l |
Water temperature
code 0076 · °C
15.9 °C
Sampled 3 Sep 2026, 28 days ago · 26 results banked
Every result (26)
| Sampled | Result as published | Reads as |
|---|---|---|
| 3 Sep 2026, 10:59 | 15.9 | 15.9 °C |
| 10 Aug 2026, 10:50 | 15.7 | 15.7 °C |
| 8 Jul 2026, 11:09 | 17.7 | 17.7 °C |
| 4 Jun 2026, 11:09 | 13.6 | 13.6 °C |
| 7 May 2026, 08:08 | 10.4 | 10.4 °C |
| 13 Apr 2026, 14:03 | 10.9 | 10.9 °C |
| 4 Mar 2026, 10:41 | 8.7 | 8.7 °C |
| 10 Feb 2026, 08:12 | 8.2 | 8.2 °C |
| 14 Jan 2026, 07:55 | 4.9 | 4.9 °C |
| 18 Mar 2025, 10:04 | 7.1 | 7.1 °C |
| 6 Feb 2025, 09:33 | 5.7 | 5.7 °C |
| 22 Jan 2025, 07:32 | 6.8 | 6.8 °C |
| 2 Dec 2024, 09:00 | 9.3 | 9.3 °C |
| 18 Nov 2024, 09:18 | 8.7 | 8.7 °C |
| 17 Oct 2024, 09:18 | 12.7 | 12.7 °C |
| 16 Sep 2024, 11:17 | 12.7 | 12.7 °C |
| 19 Aug 2024, 13:07 | 14.4 | 14.4 °C |
| 17 Jul 2024, 10:36 | 14.2 | 14.2 °C |
| 17 May 2024, 11:58 | 13.7 | 13.7 °C |
| 17 Apr 2024, 08:24 | 8.5 | 8.5 °C |
| 18 Mar 2024, 08:40 | 9.7 | 9.7 °C |
| 21 Feb 2024, 11:23 | 10 | 10 °C |
| 16 Jan 2024, 08:59 | 3.7 | 3.7 °C |
| 8 Dec 2023, 16:00 | 7.3 | 7.3 °C |
| 22 Nov 2023, 08:36 | 8 | 8 °C |
| 16 Oct 2023, 08:45 | 7 | 7 °C |
pH
code 0061
7.92
Sampled 3 Sep 2026, 28 days ago · 26 results banked
Every result (26)
| Sampled | Result as published | Reads as |
|---|---|---|
| 3 Sep 2026, 10:59 | 7.92 | 7.92 |
| 10 Aug 2026, 10:50 | 8.19 | 8.19 |
| 8 Jul 2026, 11:09 | 8.09 | 8.09 |
| 4 Jun 2026, 11:09 | 8.04 | 8.04 |
| 7 May 2026, 08:08 | 7.97 | 7.97 |
| 13 Apr 2026, 14:03 | 8.61 | 8.61 |
| 4 Mar 2026, 10:41 | 8.1 | 8.1 |
| 10 Feb 2026, 08:12 | 8.01 | 8.01 |
| 14 Jan 2026, 07:55 | 8.08 | 8.08 |
| 18 Mar 2025, 10:04 | 8.04 | 8.04 |
| 6 Feb 2025, 09:33 | 8.19 | 8.19 |
| 22 Jan 2025, 07:32 | 7.91 | 7.91 |
| 2 Dec 2024, 09:00 | 7.85 | 7.85 |
| 18 Nov 2024, 09:18 | 7.81 | 7.81 |
| 17 Oct 2024, 09:18 | 7.8 | 7.8 |
| 16 Sep 2024, 11:17 | 7.98 | 7.98 |
| 19 Aug 2024, 13:07 | 8.26 | 8.26 |
| 17 Jul 2024, 10:36 | 8.04 | 8.04 |
| 17 May 2024, 11:58 | 8.02 | 8.02 |
| 17 Apr 2024, 08:24 | 7.94 | 7.94 |
| 18 Mar 2024, 08:40 | 7.89 | 7.89 |
| 21 Feb 2024, 11:23 | 8.04 | 8.04 |
| 16 Jan 2024, 08:59 | 8.12 | 8.12 |
| 8 Dec 2023, 16:00 | 7.99 | 7.99 |
| 22 Nov 2023, 08:36 | 7.83 | 7.83 |
| 16 Oct 2023, 08:45 | 8.03 | 8.03 |
Ammonia
ammoniacal nitrogen as N · code 0111 · mg/l
0.067 mg/l
Sampled 3 Sep 2026, 28 days ago · 26 results banked
Every result (26)
| Sampled | Result as published | Reads as |
|---|---|---|
| 3 Sep 2026, 10:59 | 0.067 | 0.067 mg/l |
| 10 Aug 2026, 10:50 | 0.07 | 0.07 mg/l |
| 8 Jul 2026, 11:09 | 0.049 | 0.049 mg/l |
| 4 Jun 2026, 11:09 | 0.054 | 0.054 mg/l |
| 7 May 2026, 08:08 | 0.032 | 0.032 mg/l |
| 13 Apr 2026, 14:03 | <0.03 | below 0.03 mg/l (not detected above this) |
| 4 Mar 2026, 10:41 | <0.03 | below 0.03 mg/l (not detected above this) |
| 10 Feb 2026, 08:12 | 0.043 | 0.043 mg/l |
| 14 Jan 2026, 07:55 | 0.055 | 0.055 mg/l |
| 18 Mar 2025, 10:04 | <0.03 | below 0.03 mg/l (not detected above this) |
| 6 Feb 2025, 09:33 | <0.03 | below 0.03 mg/l (not detected above this) |
| 22 Jan 2025, 07:32 | 0.051 | 0.051 mg/l |
| 2 Dec 2024, 09:00 | 0.031 | 0.031 mg/l |
| 18 Nov 2024, 09:18 | <0.03 | below 0.03 mg/l (not detected above this) |
| 17 Oct 2024, 09:18 | <0.03 | below 0.03 mg/l (not detected above this) |
| 16 Sep 2024, 11:17 | 0.034 | 0.034 mg/l |
| 19 Aug 2024, 13:07 | <0.03 | below 0.03 mg/l (not detected above this) |
| 17 Jul 2024, 10:36 | 0.049 | 0.049 mg/l |
| 17 May 2024, 11:58 | <0.03 | below 0.03 mg/l (not detected above this) |
| 17 Apr 2024, 08:24 | <0.03 | below 0.03 mg/l (not detected above this) |
| 18 Mar 2024, 08:40 | <0.03 | below 0.03 mg/l (not detected above this) |
| 21 Feb 2024, 11:23 | 0.04 | 0.04 mg/l |
| 16 Jan 2024, 08:59 | 0.053 | 0.053 mg/l |
| 8 Dec 2023, 16:00 | 0.063 | 0.063 mg/l |
| 22 Nov 2023, 08:36 | 0.034 | 0.034 mg/l |
| 16 Oct 2023, 08:45 | 0.075 | 0.075 mg/l |
Nitrate
as nitrogen (N) · code 0117 · mg/l
5.28 mg/l
Sampled 3 Sep 2026, 28 days ago · 26 results banked
Every result (26)
| Sampled | Result as published | Reads as |
|---|---|---|
| 3 Sep 2026, 10:59 | 5.28 | 5.28 mg/l |
| 10 Aug 2026, 10:50 | 5.98 | 5.98 mg/l |
| 8 Jul 2026, 11:09 | 4.67 | 4.67 mg/l |
| 4 Jun 2026, 11:09 | 4.07 | 4.07 mg/l |
| 7 May 2026, 08:08 | 4.57 | 4.57 mg/l |
| 13 Apr 2026, 14:03 | 5.28 | 5.28 mg/l |
| 4 Mar 2026, 10:41 | 5.49 | 5.49 mg/l |
| 10 Feb 2026, 08:12 | 4.88 | 4.88 mg/l |
| 14 Jan 2026, 07:55 | 4.48 | 4.48 mg/l |
| 18 Mar 2025, 10:04 | 7.79 | 7.79 mg/l |
| 6 Feb 2025, 09:33 | 7.49 | 7.49 mg/l |
| 22 Jan 2025, 07:32 | 6.98 | 6.98 mg/l |
| 2 Dec 2024, 09:00 | 6.07 | 6.07 mg/l |
| 18 Nov 2024, 09:18 | 6.57 | 6.57 mg/l |
| 17 Oct 2024, 09:18 | 6.17 | 6.17 mg/l |
| 16 Sep 2024, 11:17 | 4.78 | 4.78 mg/l |
| 19 Aug 2024, 13:07 | 4.69 | 4.69 mg/l |
| 17 Jul 2024, 10:36 | 4.38 | 4.38 mg/l |
| 17 May 2024, 11:58 | 6.46 | 6.46 mg/l |
| 17 Apr 2024, 08:24 | 7.08 | 7.08 mg/l |
| 18 Mar 2024, 08:40 | 7.28 | 7.28 mg/l |
| 21 Feb 2024, 11:23 | 5.48 | 5.48 mg/l |
| 16 Jan 2024, 08:59 | 6.38 | 6.38 mg/l |
| 8 Dec 2023, 16:00 | 3.87 | 3.87 mg/l |
| 22 Nov 2023, 08:36 | 3.26 | 3.26 mg/l |
| 16 Oct 2023, 08:45 | 4.08 | 4.08 mg/l |
Phosphate
orthophosphate, reactive, as P · code 0180 · mg/l
0.041 mg/l
Sampled 3 Sep 2026, 28 days ago · 26 results banked
Every result (26)
| Sampled | Result as published | Reads as |
|---|---|---|
| 3 Sep 2026, 10:59 | 0.041 | 0.041 mg/l |
| 10 Aug 2026, 10:50 | 0.011 | 0.011 mg/l |
| 8 Jul 2026, 11:09 | 0.03 | 0.03 mg/l |
| 4 Jun 2026, 11:09 | 0.032 | 0.032 mg/l |
| 7 May 2026, 08:08 | 0.024 | 0.024 mg/l |
| 13 Apr 2026, 14:03 | 0.018 | 0.018 mg/l |
| 4 Mar 2026, 10:41 | 0.033 | 0.033 mg/l |
| 10 Feb 2026, 08:12 | 0.027 | 0.027 mg/l |
| 14 Jan 2026, 07:55 | 0.033 | 0.033 mg/l |
| 18 Mar 2025, 10:04 | 0.016 | 0.016 mg/l |
| 6 Feb 2025, 09:33 | 0.031 | 0.031 mg/l |
| 22 Jan 2025, 07:32 | 0.033 | 0.033 mg/l |
| 2 Dec 2024, 09:00 | 0.031 | 0.031 mg/l |
| 18 Nov 2024, 09:18 | 0.03 | 0.03 mg/l |
| 17 Oct 2024, 09:18 | 0.034 | 0.034 mg/l |
| 16 Sep 2024, 11:17 | 0.02 | 0.02 mg/l |
| 19 Aug 2024, 13:07 | 0.035 | 0.035 mg/l |
| 17 Jul 2024, 10:36 | 0.03 | 0.03 mg/l |
| 17 May 2024, 11:58 | 0.027 | 0.027 mg/l |
| 17 Apr 2024, 08:24 | 0.025 | 0.025 mg/l |
| 18 Mar 2024, 08:40 | 0.035 | 0.035 mg/l |
| 21 Feb 2024, 11:23 | 0.04 | 0.04 mg/l |
| 16 Jan 2024, 08:59 | 0.057 | 0.057 mg/l |
| 8 Dec 2023, 16:00 | 0.031 | 0.031 mg/l |
| 22 Nov 2023, 08:36 | 0.031 | 0.031 mg/l |
| 16 Oct 2023, 08:45 | 0.04 | 0.04 mg/l |
Conductivity
at 25 °C · code 0077 · µS/cm
657 µS/cm
Sampled 3 Sep 2026, 28 days ago · 26 results banked
Every result (26)
| Sampled | Result as published | Reads as |
|---|---|---|
| 3 Sep 2026, 10:59 | 657 | 657 µS/cm |
| 10 Aug 2026, 10:50 | 638 | 638 µS/cm |
| 8 Jul 2026, 11:09 | 651 | 651 µS/cm |
| 4 Jun 2026, 11:09 | 648 | 648 µS/cm |
| 7 May 2026, 08:08 | 639 | 639 µS/cm |
| 13 Apr 2026, 14:03 | 638 | 638 µS/cm |
| 4 Mar 2026, 10:41 | 670 | 670 µS/cm |
| 10 Feb 2026, 08:12 | 752 | 752 µS/cm |
| 14 Jan 2026, 07:55 | 789 | 789 µS/cm |
| 18 Mar 2025, 10:04 | 655 | 655 µS/cm |
| 6 Feb 2025, 09:33 | 647 | 647 µS/cm |
| 22 Jan 2025, 07:32 | 850 | 850 µS/cm |
| 2 Dec 2024, 09:00 | 655 | 655 µS/cm |
| 18 Nov 2024, 09:18 | 647 | 647 µS/cm |
| 17 Oct 2024, 09:18 | 641 | 641 µS/cm |
| 16 Sep 2024, 11:17 | 700 | 700 µS/cm |
| 19 Aug 2024, 13:07 | 644 | 644 µS/cm |
| 17 Jul 2024, 10:36 | 652 | 652 µS/cm |
| 17 May 2024, 11:58 | 650 | 650 µS/cm |
| 17 Apr 2024, 08:24 | 644 | 644 µS/cm |
| 18 Mar 2024, 08:40 | 655 | 655 µS/cm |
| 21 Feb 2024, 11:23 | 647 | 647 µS/cm |
| 16 Jan 2024, 08:59 | 677 | 677 µS/cm |
| 8 Dec 2023, 16:00 | 806 | 806 µS/cm |
| 22 Nov 2023, 08:36 | 771 | 771 µS/cm |
| 16 Oct 2023, 08:45 | 746 | 746 µS/cm |
Everything measured here
13 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 13 rows
| Determinand | Material | Results | First – last | Latest result |
|---|---|---|---|---|
| Oxygen, Dissolved, % Saturation 9901 | River water | 26 | Oct 2023 – Sep 2026 | 87.7% 3 Sep 2026 |
| Oxygen, Dissolved as O2 9924 | River water | 26 | Oct 2023 – Sep 2026 | 8.65 mg/l 3 Sep 2026 |
| Temperature of Water 0076 | River water | 26 | Oct 2023 – Sep 2026 | 15.9 °C 3 Sep 2026 |
| pH 0061 | River water | 26 | Oct 2023 – Sep 2026 | 7.92 3 Sep 2026 |
| Ammoniacal Nitrogen as N 0111 | River water | 26 | Oct 2023 – Sep 2026 | 0.067 mg/l 3 Sep 2026 |
| Nitrate as N 0117 | River water | 26 | Oct 2023 – Sep 2026 | 5.28 mg/l 3 Sep 2026 |
| Orthophosphate, reactive as P 0180 | River water | 26 | Oct 2023 – Sep 2026 | 0.041 mg/l 3 Sep 2026 |
| Conductivity at 25 C 0077 | River water | 26 | Oct 2023 – Sep 2026 | 657 µS/cm 3 Sep 2026 |
| Alkalinity to pH 4.5 as CaCO3 0162 | River water | 26 | Oct 2023 – Sep 2026 | 270 mg/l 3 Sep 2026 |
| Ammonia un-ionised as N 0119 | River water | 26 | Oct 2023 – Sep 2026 | 0.00157 mg/l 3 Sep 2026 |
| BOD : 5 Day ATU 0085 | River water | 18 | Feb 2024 – May 2026 | 1.3 mg/l 7 May 2026 |
| Nitrite as N 0118 | River water | 26 | Oct 2023 – Sep 2026 | 0.025 mg/l 3 Sep 2026 |
| Nitrogen, Total Oxidised as N 0116 | River water | 26 | Oct 2023 – Sep 2026 | 5.3 mg/l 3 Sep 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.