You can access the Water Quality Archive here:
The Water Quality Archive provides data on water quality measurements. Samples are taken at sampling points around England and can be from coastal or estuarine waters, rivers, lakes, ponds, canals or groundwaters. They are taken for a number of purposes including compliance assessment against discharge permits, investigation of pollution incidents or environmental monitoring. The archive provides data on measurements and samples dating from 2000.
The data is updated within two working days of a new sample being added. We also do a complete data refresh each month which may include corrections to earlier data.