The company is planning to replace an existing pipe that runs from Lemon Grove to North Road.
Working with Darlington Borough Council, Northumbrian Water will also be completing localised surface water drainage work at the junction of Lime Avenue and Mayfair Road. This will help improve the way rain water is dispersed from the area, reducing the chances of flooding during storm conditions.
While some road closures will be necessary during the course of the project, which is expected to begin in the summer and run for approximately seven months, this will be minimised by the use of trenchless techniques, where possible.
This involves digging small pits and drilling horizontally, rather than having to dig a trench. This will remove the need for lane or road closures as the work crosses the A167 and the entrance to Lemon Grove.
Customers in the area will be given advance notice of further details of the project, including traffic management and road closures, and this information will also be available on Northumbrian Water's online community portal at www.nwlcommunityportal.co.uk. Once on the site, visitors should follow the link to the Harrowgate Hill Rising Main page.
Project Manager Paul Davison said: "Upgrading the local sewer network will help to reduce the risk of flooding or pollution, so this investment is good news for customers and the environment.
"The use of trenchless technology will help to reduce impact for customers and commuters in the area, and we will work wherever possible to minimise disruption throughout the project."