This guide has moved
Our reverse osmosis guide has been expanded with named systems, current Canadian prices, a contaminant comparison table and running costs.
Reverse osmosis pushes water through a membrane fine enough to block dissolved solids, reducing nitrate, arsenic, fluoride, sodium and total dissolved solids — none of which activated carbon removes. It wastes some water to drain, works slowly, and strips beneficial minerals unless the system remineralises. For most Canadians on treated municipal water, a carbon block filter is the better buy.