Drinking water from Metro Vancouver's Coquitlam reservoir is now being disinfected using ultraviolet light.
The $100-million project has been in operation for six months and officially opened Wednesday, but residents are unlikely to have tasted any difference.
"You will not notice a thing," Metro Vancouver utilities committee chair Darrell Mussatto said. "It doesn't change the taste, the colour – anything at all."
The Coquitlam reservoir typically serves the eastern third of the region – Coquitlam, Port Coquitlam, Maple Ridge and parts of Surrey and Langley.
Previously, a combination of ozonation and chlorination was used for the Coquitlam reservoir water.
It now passes under eight banks of ultraviolet lights that zap chlorine-resistant organisms like cryptosporidium and giardia that can make people sick.
Some chlorine will still be added at the end of the process to prevent pathogens from re-growing further along in the Metro water main system, but less will be used than in the past.
The disinfection upgrade was made to comply with revised federal drinking water standards that required a higher level of treatment.
"This will greatly exceed the regulations," Mussatto said, but added Metro had no option.
He said the old system was "perfectly safe" but new standards extended to Metro's protected reservoirs even though they were mainly geared to protect more vulnerable well water systems from a repeat of the deadly drinking water contamination tragedy of 2000 in Walkerton, Ontario.
The region previously opened a much more costly filtration plant to treat water from the Seymour and Capilano reservoirs.
Two years ago, Metro reps worried that a further rule change might be ordered by Ottawa forcing a filtration system at Coquitlam as well, but Mussatto is no longer concerned that will happen.
"The Coquitlam is a much bigger watershed and they get much less sediment in their water," he said. "There's no need for filtration there and we don't anticipate any in the future."
The reservoir's main challenge will eventually be serving the demand of the growing region.
The dam may need to be raised eventually, but Mussatto said that may be up to 50 years away.
The UV project came in somewhat under the original $110 million budget.
Metro Vancouver provides a billion litres of water each day to about half of B.C.'s population.
Coquitlam reservoir