The Mayflower site, which cost £60 million, will replace the company’s Crownhill treatment works, which has served the area since the 1950s.
The new plant uses a novel process to treat water, featuring suspended ion exchange, inline coagulation and ceramic membrane microfiltration. South West said this is the first instance of these technologies being used together.
The system treats up to 90megalitres of water daily and uses an ozone system for cleaning membranes to keep them working efficiently.
A prototype installation of the system was trialled at the Crownhill works between 2013 and 2015 after being developed by Dutch company PWNT.
Since August, Mayflower has been treating water blended with output from Crownhill, with the proportion gradually increased for a smooth transition of public supply.
James King, South West’s director of operations for drinking water services, described this as a “truly significant milestone” for the company, customers and water industry.
“We already produce some of the highest quality drinking water in the UK, but Mayflower does so extremely consistently and efficiently,” King said. “Mayflower will meet the needs of Plymouth’s growing population and provide a secure, high-quality drinking water supply for the wider Plymouth area for generations to come.”