How clean is clean? How pure is pure? Answers generally vary, especially when it comes to what flows out of a home’s faucets.
Few topics elicit the kind of public reaction sparked by the issue of residential drinking water. The response is a natural one given the inexact science of . . . science. We know water considered safe just five or 10 years ago might not be today. Who’s to say that what looks harmless in today’s test tube might not be deemed harmful later?
As a result, water termed “clean” by a lab may not be clean enough for many homeowners’ tastes. “Safe” water sounds even murkier to those fed up with the odd odors of some city water or the lingering taste of wells.
What’s in your pipes? Your well? What has the city left in or taken out? Most homeowners can’t be sure, perhaps giving reason to the fact that sales of bottled water have never been higher. According to a recent local study done by the Water Quality Association in Lisle, one in three people believe their water is not as safe as it should be.
More and more homeowners, however, are looking to add on or build-in home filtration systems as a cost-effective way to improve water for drinking, laundry and bathing. While more than 500 brands of filters are available, up to now most have been based on a handful of basic systems costing anywhere from $20 to $1,500-plus:
– Distillation: Heating water to the point of vapor to remove minerals. This process can leave water tasting flat and does not remove many non-mineral impurities.
– Activated carbon: Carbon is “activated” by firing it in a furnace to increase its surface area, not unlike the physics of popcorn. Water passed though activated carbon powder (in conjunction with a solid filter) is the most common form of filtration found in home units, such as those that attach directly to a faucet. While carbon does trap many impurities, bacteria caught can multiply in the warm, moist environment of the filter, which must be changed regularly.
– Reverse osmosis (or RO): Uses a semi-permeable (often ceramic) membrane to filter water at a very fine level. RO does result in better tasting water but is not terribly efficient. Considerable water can be wasted in treatment and, again, impurities may sneak through.
– Ion exchange: Uses microscopic spheres of plastic coated with charged particles to attract and remove targeted impurities. Such resin applications have been the basis for water softener systems for years. Consumer systems such as Brita use ion exchange in combination with activated carbon. Not all impurities are removed and the resin has a finite lifespan, again requiring regular filter replacement.
Many of these systems continue to enjoy mass market popularity in one form or another. However, there are new consumer systems on the horizon based on technology that might seem more at home on board the space shuttle than under your sink.
There is still no magic bullet, no single “clean-all” system. However, used in combination the following systems do seem to promise new levels of performance:
– Carbon block filters (cost, $150 and up): The technology of activated carbon applied in a solid brick form to clean water at a much finer level than traditional activated carbon powder. One gram of carbon has the molecular surface area of a football field, and as a result, serves as a powerful absorption medium for chemical impurities. The combination of mechanical straining and chemical bonding has proven to be very effective when combined with other devices for the removal of bacteria.
– Ultraviolet light, or UV (starting at $400): Kills bacteria with ultraviolet light rays. Typically used in conjunction with a carbon block or other solid filter, the system prevents bacteria from reproducing. A high-power UV bulb illuminates water as it passes through clear tubing. The tubing must be kept as clear as possible and the UV rays are not effective on chemicals or lead.
– Ozone (ozonation, starting at $1,500): Ozone is the result of electrically broken and recombined oxygen molecules (the “clean” smell following a lightning storm). In water treatment, ozone is electrically generated and then applied to water to instantly break down the cell walls of various types bacteria. A popular system in Europe, ozonation is beginning to forge a residential market in the U.S.
So are the new gee-whiz systems worth the cost? According to Peter Censky, executive director of the Water Quality Institute, it depends on why you think you need a filter. While activated under-counter carbon/RO combinations costing a few hundred dollars are considered very thorough today, the quality bar is always being raised.
“Water today is truly safer than ever and science says the current state of regulation is pretty good, but that’s right now,” Censkey says. “A few years ago, science said you didn’t have to worry about 50 parts-per-billion (ppb) of lead and now 5 to 10 (ppb) is considered high but tolerable.”
Censkey adds that taste is also an increasingly important consumer issue.
For additional information, check out the following sites:
NSF International, tests and certifies water systems
http://www.nsf.org/
Multi-Pure, background on systems, residential needs
http://pwn.com/guide.html
Ozonet, ozone systems http://www.primenet.com/ozone/index.html
JacPac, UV systems
http://iceonline.com/home/rodc/uvkill.html
For information on how to have your home’s water tested, call the Water Quality Association at 1-800-749-0234.
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Don Hunt and Brian Edwards write about technology related to buying, renting and fixing homes. They can be reached via e-mail at hitekhome@aol.com, or you can write to them: The High-Tech Home, Chicago Tribune, Your Place section, 435 N. Michigan Ave. 4th Floor, Chicago, Ill, 60611.
