Installing water filtration in the Paddy Ryan Reservoir would come with a price tag running into the millions of dollars.

During discussion in a recent District of Invermere council meeting, chief administrative officer Chris Prosser had brought up the cost in response to points raised by Invermere councillor Paul Denchuk, who had suggested (before learning of the costs) that installing filtration at Paddy Ryan would be more effective than offering rebates for filter installation in individual homes in Invermere that have water problems.

Prosser later clarified to The Valley Echo that he had referred to estimates for various options of municipal water treatment included in a cost-benefits analysis in the 2011 Water Treatment and Supply Report prepared for the district by planning company Urban Systems.

The report puts the cost of water filtration for the Paddy Ryan Reservoir somewhere in the neighbourhood of $15 million to $18 million, rising to more than $20 million dollars by 2023.

It puts the cost of installing UV disinfection at reservoir (which is the option the district has chosen to proceed with) at just over one million dollars (the figure mentioned at the council meeting was $1.3 million). Another table in the report translates the cost of the different water treatment options into a per-cubic-metre basis, with water filtration at Paddy Ryan costing $1.67 per cubic metre and UV disinfection at Paddy Ryan costing$0.31 per cubic metre.

Not only does filtration come with significantly higher capital costs, Prosser said, but also operating costs would be almost three times what the district currently pays.

The UV disinfection to be set up at Paddy Ryan will be in addition to the chlorine disinfection already in place.