Turning the Tide: Real-Time Sewer Spill Alerts and a Cleaner Future for the Thames

How We Pushed Thames Water to Publish Real-Time Sewer Alerts

The Thames Water sewer overflow map.

Four years of campaigning and the support of more than 700 people saw the company give in and publish the data live.

We were the first organisation to spot and use a clause in the Environmental Information Regulations 2004 that legally required the data to be put online.

We took the company to the brink of a Judicial Review to make them change their position.

Working on real-time information since 2015

In 2013 the Secretary of State told water companies to fit monitors on all of their sewer overflows. We waited a few years and then sent an information request to Thames Water in December 2016. We asked them how many sewer overflows to the Tidal Thames there had been the previous year. This revealed that of the 36 sites that discharged they had no idea what was happening at two thirds of them. This was a surprise, but it also exposed that the company had very little data to base investment decisions on.

The number of monitors gradually increased, and once it exists, this data is required by law to be available to the public on request. Our innovation was to identify a clause within the Environmental Information Regulations that required the overflows to be published online, in real-time. No one had made this connection before - organisations and individuals used an earlier clause that gives a public body 20 working days to reply to an information request (not much use if you want to know if a sewer is spilling now). We checked with pro bono lawyers from Leigh Day (via the Environmental Law Foundation) and they confirmed our interpretation of the law. It was clear that the system wasn’t functioning properly, there was a lack of accountability, poor data and the law not being applied.

In the early stages of this process Thames Water refused to engage with us. They ignored our emails. We had made it clear to them that they were not obeying the law. No company gets to choose which laws they abide by and which they ignore.

Pressurising Thames Water

In 2017 we set up an email on our website that members of the public could send. It asked Thames Water how many of their sewers had overflowed and to meet their legal obligations re data display. More than 700 people sent them and it overwhelmed their information department. This was to make the point that it would be easier for them to put the spills online rather respond to every request.

Soon after that we met with their Director of Sustainability and their Director of Wastewater in 2018. They said they would do it voluntarily, but after a few years they had not, so we formally complained to the company, they responded rejecting our complaint so we complained to the Information Commissioner’s Office. They backed Thames Water, so we then said we would take the company to Judicial Review. We kept asking people to send EIR requests every time it rained.

When the Environment Bill was first introduced by the Government in January 2020 there was no reference to overflows having to be put online in real-time. We had been campaigning on this issue for almost 4 years, and more people were now aware of it. In June 2021 we met with Thames Water and they committed to putting their overflows online.

The requirement for all water companies to do this was first added as an amendment to the Environment Bill in the September 2021 version by the House of Lords. In October of that year the Thames Water CEO told the Environmental Audit Committee that they were going to do it by the end of 2022. It appeared online in January 2023.