Water filters and reverse osmosis systems are sold with long lists of claims. This checklist uses Health Canada guidance, credited below, and applies it to a real retailer. It is general information, not health advice.
1. Ask whether you need one
Health Canada's questions and answers on drinking water treatment devices says water that meets the Guidelines for Canadian Drinking Water Quality does not usually require additional treatment for health-related reasons, and that well, lake or river users should test regularly and consult a qualified water treatment specialist if the water does not comply.
2. Buy a certified device
Health Canada strongly recommends buying a device certified to the applicable ANSI/NSF standard, looking for a certification mark and a statement of conformity, and reviewing packaging and promotional literature to see which performance claims were verified. Check the exact model on the certifier's listing.
3. Know what RO removes
The same page says reverse osmosis systems remove minerals like calcium and magnesium, and that water is a minor source of these compared with food. Some systems add minerals back, which is a design choice, not a health claim you can verify from a banner.
4. Plan for maintenance
Health Canada says maintenance is very important to ensure continued efficacy. Add up the annual filter costs and check how often cartridges must be replaced.
5. Read the return terms
Check the window, whether the system must be disassembled and repackaged, who pays return shipping and any restocking fee after the window.
An example: checking a retailer against the list
In our Waterdrop Canada review we applied these questions. The retailer offers a 30-day return with no restocking fee, but the buyer pays return shipping, the system must be repackaged and certification must be checked model by model.
A note on the sources
Health Canada is the Government of Canada's health department. We wrote this article in our own words and it is not health advice. Some links to brands on this site are affiliate links; see our affiliate disclosure.