Environment Agency - Understanding data - https://environment.data.gov.uk/bwq/profiles/help-understanding-data.html

Interactive map with the latest British and Irish river level, flow and groundwater - https://www.gaugemap.co.uk/

Surfers Against Sewage - https://www.sas.org.uk/

Thames Water Storm Discharge Information - https://www.thameswater.co.uk/about-us/performance/river-health/storm-discharge-and-event-duration-monitoring