This chart is compiled from weekly analyses which are averaged to produce quarterly results for each of the sampling sites. You can find all our previous years’ quarterly results on our Data Logger – just scroll down for the link to this.

Measurement units: milligrams per litre of sampled water (mg/l).

For phosphates (expressed as elemental phosphorus P) good quality is at or below the level of 0.1 mg/l and is shown as the horizontal line on the chart.