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On Tap
by author Josie Padro

A tall glass of ice water: clear and simple. Whether it’s safe to drink, however, has become a complicated issue.

Municipal water in Canada is regularly tested for microbial contamination and must meet standards for taste, odour, and chemicals. Even so, city water may taste like sulphur, may contain iron that stains clothing, or may have picked up harmful elements such as lead from aging pipe systems.

Public confidence in water quality was shaken after the Walkerton, Ontario tragedy in which municipal water contaminated with E. coli led to seven deaths and over 2,000 illnesses. Especially vulnerable to poor water quality are small children, pregnant women, people with lowered disease immunity, and the elderly.

Residents of smaller communities or those who depend on well water have additional quality concerns. According to Associate Professor of Chemical and Biological Engineering at the University of British Columbia, Madjid Mohseni, water quality in some rural areas of Canada can be “as bad or worse than that in developing countries.” Whether in the city or the countryside, many consumers are turning to water purification and filtration systems.

Navigating water purification systems

Since no one system removes all contaminants, you’ll want to buy the one best suited to your home water supply. The water authority in your municipality or territory can provide information about water quality in your area; some post regular water quality reports on their websites. To find out exactly what’s in the water coming out of your tap, however, you will need to have a sample tested. Check the local phone directory or the Internet to find an independent laboratory to analyze your water.

As you explore water treatment alternatives, it’s important to ensure that whichever system you choose is certified by one of three organizations:

• The Canadian Standards Association (CSA)
• Underwriters Laboratory (UL)
• NSF International

Water treatment systems can be as simple as a refillable carafe that requires an occasional filter change, or as sophisticated as a large plumbed-in system that treats all the water entering your home. Here are some of the more common technologies used to remove impurities from drinking water.

Filtration

Water filters are made from a number of materials. Each is effective for removing some, but not all impurities, so they are often used in combination. Filters improve the taste, smell, and appearance of drinking water but are not intended to remove infectious organisms. For this reason they should be used with treated water, such as that from a municipal system.

Type of filter	Uses
activated charcoal	used in most refillable pitcher systems; charcoal attracts contaminants to its porous surface, removing them from the water; it can filter out chlorine, lead, asbestos, mercury, and copper
ceramic and fibre	both effective for removing particles from water; available in different pore sizes, which are measured in microns; cannot remove dissolved chemicals such as lead, mercury, and sodium
resin	remove lead; useful for treating hard water (while hard water is not harmful, it is high in dissolved minerals such as calcium and magnesium which can build up in appliances)

It is important to change filters according to instructions, since bacteria can grow in accumulated material, and in the end, create extremely contaminated water.

Reverse osmosis

Reverse osmosis forces water through a membrane which filters out bacteria and minerals such as chromium, mercury, copper, chloramines, and arsenic. It will also remove sodium and potassium, making a reverse osmosis unit handy for those whose diets must limit these elements. Since it does not sterilize water, it should be used with water that has been deemed safe to drink.

For every litre of filtered water, reverse osmosis systems produce 2 to 5 litres of waste water called brine. Also to function properly, water pressure in the system must be greater than 45 psi (pounds per square inch). Homes with lower water pressure may need a booster pump.

UV water treatment

UV systems come in all sizes—from small countertop units to larger ones that can treat all water entering the house. UV systems, which require a 110-volt outlet, expose water to ultraviolet light that inactivates any bacteria, molds, parasites, and viruses that might be present. A pre-filter is often installed to remove particles and metals from the water. Pre-filtration will also improve the water’s clarity, making UV treatment more effective.

Maintaining a UV system is fairly straightforward. The bulb should be changed once a year as it loses its effectiveness even if it hasn’t burned out. The quartz sleeve that surrounds the bulb should be checked every month to make sure it stays clean and clear. While UV inactivates troublesome critters in the water, it is not meant to be used on wastewater or water that is obviously contaminated.

Water works

Purified water can be delivered through a number of devices.

Device	Uses and benefits
refillable carafes	cheapest and simplest way to filter water; most have built-in indicators that remind you when to insert a new filter
faucet-mounted systems	easily installed on most faucets; water is filtered as it flows through the tap
countertop systems	filter large amounts of water on demand; take up counter space, but many are quite compact and less cumbersome than faucet-mounted filters
under-sink systems	filter large quantities of water on demand; must be plumbed into existing water pipes, reducing countertop clutter
whole-house systems	designed to treat a large amount of water; plumbed into the main water supply; costly to buy and install

If you decide you need a water purification system, selecting one that’s right for you takes a little research. It’s a matter of finding out what’s in your water and then choosing a system that fits within your budget and lifestyle. 

Josie Padro is a health and lifestyles writer.

Source: alive #322. August 2009