Tees Cottage Pumping Station in Darlington was built in 1849 to provide clean drinking water to Darlington and the surrounding areas of Teesside.
Featuring its 1904 beam engine, and the largest fully operational historic gas engine in Europe, the Scheduled Ancient Monument was converted into a museum in 1980, run by volunteers.
This weekend, visitors will be able to take a look behind the scenes - seeing first-hand the mechanical marvels such as the giant engines and water pumps in action, as well as the iron work demonstrations in the smithy.
A small number of vintage vehicles will also be on display and people can even take a ride on the miniature railway, or relax in the tearoom with a cake and a cup of tea.
Ross Smith, Partnerships Manager at Northumbrian Water, said: "Tees Cottage Pumping Station is a fantastic example of heritage right here on our doorstep.
“We’re immensely proud of this historic monument and of the longstanding partnership we have with the volunteers of Tees Cottage Pumping Station, who work exceptionally hard helping us to preserve it for generations to come.”
Chairman and Operations Director David Smart, who has been volunteering at Tees Cottage Pumping Station for the last nine years, said: "The team of volunteers are working hard to get everything ready for our opening weekend and we are very excited to welcome visitors through the doors.
“It’s a great opportunity for people to get a glimpse of how this Victorian waterworks operated and there is so much to see and do.”
Tees Cottage Pumping Station is open to the public on Saturday 25 and Sunday 26 June between 11am and 5pm - with last entry at 4pm. The site is located next to the River Tees on Coniscliffe Road, Darlington DL3 8FT.
There is a small entrance charge of £5.00 for adults, £4.00 for concessions and children under 16 go free when accompanied by an adult. All money raised during opening days is invested into the continued improvements to this historic monument. There is a small charge for train rides on the miniature railway operated by Tees Cottage Miniature Railway.
For more information about Tees Cottage Pumping Station visit, www.teescottage.co.uk