The Ins and Outs of Home Water Purification Systems

There are at least a half-dozen different ways to purify your water at home, but what are the differences between various devices and what method fits your water needs the best? From charcoal filters to reverse osmosis to ultraviolet light, the choices can bewilder.Here’s a quick guide to some of the most common at-home water purification systems, from those that attach to your tap to devices that work off-faucet.

Whole House Filtration:

For a unit that costs about $800 and comes with an average installation price of $250–$350 (according to, you can introduce a filter – usually one that uses coconut-carbon technology – between your water source’s point of entry and every tap in your house. The folks at recommend that homeowners using this system still filter their kitchen water with a second method.


At an average price of $150 (, these units connect to your pipes just before the water comes out of your sink’s faucet. Typically used in the kitchen, they tend to terminate in a separate dispenser attached at the sink’s sprayer hole. The technology available varies:

A) Reverse Osmosis:

These devices are meant to filter out minerals. The water is drawn through a membrane, then pressurized and redistributed, leaving solids behind. One drawback, according to some scientists, is that this process takes out good minerals as well as those that may be undesirable.

B) Ultraviolet:

This under-sink unit uses ultraviolet light to kill the organisms that live in water. It’s key to get one with an hour-counter that will tell you when the lighting element needs replacing.

C) Ionizers:

There is some debate surrounding the benefits created by these units. After electrolyzing the water that passes through them, and then separating it into two chambers – acidic and alkaline – the idea is to use the alkaline water for cooking and drinking and the acidic for washing fruits, vegetables, and kitchen items. They are typically installed either under the sink or as a countertop model, but portable units exist as well. The price can run to more than $1,500.


Connecting to the faucet at its aeration point, water is either delivered directly (Aquasana makes these, for example) or it is diverted to a filter (or series of filters). Depending on the complexity of the system, these can range from $99 to about $350. See a selection of companies and products at

Water Pitcher Filtration:

This most commonly comes in the form of a plastic pitcher with a replaceable charcoal filter. From Brita to PUR to 3M, a variety of sizes and designs average $20 to $25 for the base unit, and about $6-$8 per replacement cartridge.

One step to consider before you spend any money is ordering a home water-quality test. The idea is to find out what you want filter out of your drinking water before you select a system.

Lists of accredited water testers can usually be obtained from your local office of the Ministry of Environment (here, for example). You can also stop by the Health Canada website for more information about tap-water safety.

By James O’Brien