NRW’s water quality archive provides data from samples collected around Wales, including coastal, estuary, rivers, lakes, ponds, canals, sewage discharges, trade discharges, pollution investigation points and waste sites.
NRW holds data goes back to 1962 whereas the open data product contains data from 2000 onwards. The open data product is extracted from NRW’s Water Quality database (KiWQM) and updated every month.
Some field measurements are taken in situ at the sampling station, whereas some samples are analysed in laboratories to measure aspects of the water quality. Once samples are taken, they must be processed and verified before they are added to the water quality archive. Therefore, there is a delay between samples being taken and the data being made available. Data may also be subject to change after publication, but the archive will be updated each month to include corrections.