The biggest water mains cleaning programme yet in the North-East begins next week.
Northumbrian Water is planning to clean the inside of 156 km of trunk water mains.
The £25m scheme, which will take up to four years to complete, is aimed at improving tap water quality to customers living in South East Northumberland, North Tyneside and the north of Newcastle.
Trunk water mains are large diameter pipes which transfer water around the network. Smaller diameter water pipes, known as distribution mains, then supply tap water to customers' properties.
Some of the trunk mains which will be cleaned have a diameter of up to one metre.
The first phase of preparation work, which will begin on Monday, and take up to seven months to complete, will be carried out on the trunk water mains which supply 60,000 properties in Amble, Morwick near Warkworth, Acklington, Newbiggin, Morpeth, Ashington, Blyth, Cramlington and surrounding areas.
Graham Neave, Northumbrian Water's operations director, said: "This work is in addition to upgrading 1,600km of distribution mains throughout our supply area between 2005 and 2010.
"Although discoloured water is not harmful to health we appreciate that it is not pleasant and this work will significantly reduce the risk of discoloured water to more than half a million customers."
If it is necessary to turn off the water supply prior notification will be given.
* People falsely claiming to be water company employees operate in Northumbrian Water's supply area. It is unlikely that anyone from the company will need access into a customer's property while this work is carried out.
Customers who doubt the authenticity of any caller claiming to be from Northumbrian Water or the `water board' should ring Northumbrian Water Customer Centre on 0845 717 1100.