As a result of the legislation change, which aims to resolve ownership issues, sections of drains and sewers currently owned by six million London and the Thames Valley homeowners will transfer to Thames Water, which will be responsible for the upkeep of the systems.

This will increase Thames Water’s network of sewers from 67,000km to around 107,000km, raising the 55,000 blockages a year the company currently deals with to 250,000.

Ahead of the move, Thames Valley has called on its customers to avoid ‘sewer abuse’ in a bid to limit the number of blockages it will have to deal with. It advises people not to dispose of waste such as oil, fat or other general waste such as nappies and sanitary products into the sewage system and bin it instead.

The disposable of fats down drains can lead to a build up of ‘fatbergs’, which block sewers and can in severe cases lead to sewage flooding.

Thames Water’s chief flusher, Rob Smith warned the increase in the company’s sewer network could lead to a “near fivefold increase in blockages”.

Smith said: “It’s really important people remember that just because certain sections of drainage are going to become water companies’ responsibility from 1 October does not mean that we can mistreat our sewers by putting the wrong things down them.

“Sewer abuse can lead to other people’s properties being sewer-flooded, which is a truly miserable experience and we are hell-bent on putting an end to it.”

Defra estimates that the transfer of ownership will result in an annual increase to household’s bills of between £4 and £14.

Carys Matthews

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