Question 1

Which UK water companies does WaterWatch cover?

Accepted Answer

WaterWatch covers all 9 major UK water companies: Thames Water, Yorkshire Water, Severn Trent, United Utilities, Northumbrian Water, South West Water, Southern Water, Wessex Water, and Anglian Water — totalling over 5,000 storm overflow (CSO) monitoring sites across England.

Question 2

How often is the sewage discharge data updated?

Accepted Answer

Discharge status is updated every 15 minutes from each water company's official Event Duration Monitoring (EDM) sensor network. You can see which sites are actively discharging right now on the live map.

Question 3

Is WaterWatch free to use?

Accepted Answer

Yes — WaterWatch is completely free to use. You can view the live map, browse site histories, read analysis, download data, and set up email alerts at no cost.

Question 4

What is a combined sewer overflow (CSO)?

Accepted Answer

A combined sewer overflow (CSO) is a point where untreated sewage and storm water can be released into a river or watercourse during heavy rainfall, when the combined sewer system becomes overwhelmed. UK water companies are legally required to monitor and report these events.

Question 5

How do I get free sewage discharge alerts near me?

Accepted Answer

Visit water-watch.co.uk/account to set up free email alerts. Search for monitoring sites near your river or location, subscribe, and you will receive a notification the moment a discharge starts or stops.

Question 6

How do I find sewage discharges near me?

Accepted Answer

Use the live map at water-watch.co.uk/map to see all active and recent discharges across the UK. You can also visit the Sites directory at water-watch.co.uk/sites to search by location, watercourse, or water company.

Question 7

What is Event Duration Monitoring (EDM)?

Accepted Answer

Event Duration Monitoring (EDM) is a system of electronic sensors installed at combined sewer overflow sites by UK water companies. The sensors detect when an overflow is active and report the duration electronically. Water companies are required to publish this data publicly.

Question 8

Is it safe to swim in rivers near a sewage discharge?

Accepted Answer

WaterWatch tracks which overflow sites are currently discharging and shows recent discharge history for every monitored site. This can help you make an informed decision before swimming or paddling in rivers. As a general precaution, avoid contact with water near a CSO site during or shortly after an active discharge.

Question 9

Can I download the sewage discharge data?

Accepted Answer

Yes — WaterWatch provides CSV exports of discharge data for individual sites, available from each site's page. The data includes event start times, end times, and cumulative hours.

Question 10

Is wild swimming safe near a sewage overflow?

Accepted Answer

Wild swimming carries elevated health risks during or shortly after a sewage discharge from a Combined Sewer Overflow (CSO). WaterWatch shows you exactly which sites are currently discharging and their recent discharge history, so you can make an informed decision before entering the water. As a general rule, avoid any river section downstream of an active or recently active CSO and wait at least 48 hours after a discharge has stopped before swimming.

Question 11

Which rivers have the most sewage discharges in England?

Accepted Answer

Rivers with large numbers of CSO monitoring sites — such as the Thames, Severn, Trent, Wye, Exe, and Aire — can receive significant discharge volumes during wet weather. The WaterWatch rankings and map pages let you filter by watercourse to see cumulative discharge hours for any river in England. The worst-offending sites in terms of annual spill hours are also listed on the WaterWatch Worst Offenders page.