Episode 1
In Cumbria, an army of engineers are replacing parts of an ageing monster underground pipeline that transports millions of litres of water from Haweswater Reservoir to 2 million people every day.
Episode 2
Waste Warriors James and Andy battle to clear a newly formed fatberg underneath a busy street in Manchester. It is a monstrous mass of waste and fat that is 50 metres in length
Episode 3
In Cumbria, John and his army of engineers are midway through a mammoth plumbing job, replacing parts of an ageing monster underground pipeline
Episode 4
Geoff and his elite squad of sewage cleaners must scour the pumps deep inside a holding tank at Southport Treatment works, to ensure the waste doesn't back up into people's homes
Episode 5
Project director John and his team undertake a crucial test at a fresh water pipeline in the Lake District, and a garden in Rucorn, Cheshire, is being slowly submerged in sewage.
Episode 6
Steve and Mark face one of their toughest jobs ever and Stu and Ian tackle a potential pollution emergency.
Episode 7
Stuart tackles a 200-metre fatberg in Manchester, newly qualified "leak listener" Dan detects holes in the water company's network, and the Steves attract donkey attention.
Episode 8
The largest fatberg ever seen in the North West is proving an unbeatable enemy. At 400 tonnes and 350m long, it fills 40% of the main sewer system in the docks area of Liverpool.
Episode 9
In North Wales, engineer Luke and his team of mega plumbers are mid way through a project to replace a problematic two km section of pipe that has a history of large bursts.
Episode 10
In Liverpool city centre, a crack team of drainage engineers goes underground to clear a blocked sewer.
Episode 11
Docuseries following the workers who maintain Britain's water systems.
Episode 12
