Overall score is the average of the six scored spokes. Grey spokes are not included yet.
River Wey
A snapshot of river health from a year of community sampling by Guildford Zero. Water chemistry is tested on the riverbank and E. coli samples are processed at the Community Water Lab in Zero.
133
site visits
13
sites
40
E. coli samples
RIVER HEALTH SCALE
A
Excellent 80–100
B
Good 60–80
C
Fair 40–60
D
Poor 20–40
F
Very poor 0–20
ID
Not enough data
WHAT EACH SPOKE MEANS
PPhosphate. Phosphate as phosphorus. Score: share of samples at or under 0.05 mg/L.
NNitrate. Nitrate as nitrogen. Score: share of samples at or under 2 mg/L.
TDSDissolved solids. From conductivity. Score: share of samples at or under 400 µS/cm.
CLARClarity. Stands in for turbidity. Share of visual checks rated clear.
POLPollution. Share of surveys with no foam, scum, oily sheen, litter or odour. Storm overflow data still to add.
E. coliBacteria. E. coli counts. Share of samples at or under 1,000 CFU/100 ml, the England bathing water figure.
INNSInvasive species. Invasive non-native species. Not scored yet.
INVInvertebrates. Riverfly samples: share at or above each site's trigger level.
HABHabitat. Needs a River Habitat Survey or MoRPh (Modular River Physical) survey.
Data: 10 Oct 2025 to 9 Oct 2026
contact@riverweytrust.org.uk
River Wey
Monthly averages, Oct 2025 to Oct 2026 Gaps mean no samples that month
Is it safe to swim?
Share of samples at or under 1,000 CFU/100 ml, Nov to Oct 2026
St Catherines swimming spot
17% of 24 samples
Byfleet beach
12% of 16 samples
Also spotted: On the surface: foam (5), scum (5), floating algae (1); odour: sewage (4), other (4), muddy smelling (1), petroleum (1); suspected sources noted: urban discharge (19), other (9), cows have water access upstream (1), cows in field, drinking area about 40m upstream (1), industrial discharge (1).
Sources: Guildford Zero (Water Rangers)
contact@riverweytrust.org.uk
River Wey
The wider picture
Environment Agency (EA) Ecological Status
Ecological status is the Environment Agency's official assessment of river health, based on plants, animals, water quality and the shape of the river, on a five-point scale from high to bad. It uses different measures and timescales from this community scorecard, so the two will not always agree. Together they give a fuller picture.
