Concrete dumping by firms blocking sewers in the Thames Valley

A water company has called on construction firms to be more responsible when disposing of concrete because of blockages in the sewer system.

Thames Water says the equivalent of 300 bathtubs of concrete is being discharged into its sewers each year, and it has to spend about £1.6m clearing it from pipes.

The practice is illegal and can result in enforcement action, offenders have been warned.

Tim Davies, from Thames Water, urged firms to be more "vigilant" to prevent damage as it was taking "valuable time and resource away from essential infrastructure upgrades".

The utility company said it has 60 concrete abstraction jobs running at any one time, using specialist high-power water jets to break down the waste into small pieces so it can be safely sucked out.

"The pressure is equivalent to placing the weight of a large SUV onto an area the size of a thumbnail," the company said.

Over the past 12 months engineers had spent "thousands of hours removing solidified concrete from pipes across London and the Thames Valley region", it claimed.

When left untreated, the blockages restrict wastewater flow, which can cause it to back up on to streets and in buildings, causing significant damage to pipework.

In 2019 a "concreteberg" weighing as much as 20 elephants blocked three sewers.

Davies said: "The concrete removal process can be extremely complex.

"This work requires significant investment with expensive equipment, a large team of skilled engineers, and a considerable amount of time to complete."

Investigation teams are able to trace concrete back to construction companies, which can be liable for the cost of repairs and potential prosecution.

Davies added: "My message to businesses and contractors is simple: please ensure concrete is disposed of correctly.

"Preventing this issue in the first place is far more effective than dealing with the consequences later."