A quarter of a million people living around Plymouth are now drinking water produced from a new state-of-the-art treatment works.
South West Water has started operating its £60 million Mayflower Water Treatment works at Roborough, replacing the old works at Crownhill.
The water company says it is the first of its kind in the world.
The new technology uses fewer chemicals to produce more water more efficiently and at a lower cost than before.
It works by combining suspended ion exchange, inline coagulation and ceramic membrane microfiltration.
South West Water says it is the first time that these combined technologies have been used to produce high quality drinking water anywhere in the world.
WATCH: How does it work?
The project has been ten years in the making, with expertise coming from the Netherlands.
The Crownhill works was originally constructed in open fields during the 1950s.
It was overtaken in the 21st century by construction, housing development and technology.
The new setup at Roborough is guaranteed to last for 20 years but project leaders believe it should last last indefinitely.