Our evaluation of home water treatment devices began with an examination of
distillers. All three of the units that we discussed
qualified as water purifiers (that is, the devices removed
or killed all bacterial impurities), yet they
crossed an impressively broad range of capability and cost.
Similarly, the pieces of filtration equipment we’re
reviewing in this installment vary considerably in both
capacity and price.
However, the seven filters we’ve had a chance to appraise
do have one thing in common: They all employ activated
carbon to filter out chemical impurities such
as carcinogenic trihalomethanes. (Note: Although they, too, use charcoal, the
General Ecology units rely on an even more effective
microstraining system for their primary impurity removal.)
Activated carbon — which is also called charcoal
— has been used for cleansing for over 100 years . .
. functioning, for example, as the stripping agent in World
War I gas masks and as the medium used for decolorizing
sugar. It’s only recently, however, that the versatile
material has come to be used in water filtration.
Because activated carbon’s “cleaning” ability depends
entirely on the amount of surface area contact between the cleanser and the water that’s
available, a filter’s performance is largely determined by
the volume of carbon inside it and the length of time the
water remains in contact with the carbon … a
consideration which is called “residence time.”
Unfortunately, extensive residence time can result in the
growth of bacteria on the charcoal . . . and each of the
manufacturers included in our study has dealt with that
problem in a different fashion.
American Water Purification
Both of the California-based American Water Purification
Company’s filters have silver infused into their charcoal
to inhibit any bacterial growth. In addition, the smaller
of the two units — the Water Washer — has
built-in flow control to prevent the operator from
inadvertently reducing residence time below a safe level.
Another useful feature of the limited-capacity model is a
viewing port to give the owner a visual warning when the
filter element is dirty.
The UTS Silverator is an under-sink model which can be used
either to filter all the cold water at that location, or to
deliver the cleansed liquid to its own faucet to be used
for drinking and cooking only. In the latter application,
the Silverator’s 5,000-gallon-life filter should last for a
very long time.
Bestwater Filter
The Louisville, Kentucky manufacturer’s product is by far
the most ambitious filtration setup of those we sampled.
Its capacity as well as its size is several
times that of any of the other devices . . . great enough,
in fact, to process all the water entering a household.
Furthermore, even at its maximum flow rate of two gallons
per minute, the BestWater retains water for a full two
minutes and provides about one year of filter
life. Since the unit is almost constantly in use on
a residence’s main water line, bacterial build-up
isn’t a problem.
General Ecology
Both of this company’s Seagull models are unique among
water filters because they are classed as “purifiers” by
the Environmental Protection Agency. The devices remove
bacteria — as well as cysts, amoebae, protozoa, and
small fragments of materials like asbestos — by a
microstraining process which is effective down to 0.4
microns. (For comparison, a red blood cell is about 7
microns.)
The Seagull 1.5L is a limited-capacity unit designed
primarily to purify drinking water. It is available with a
hand pump for remote use, and the filter element is
actually the body of the device. The larger model, the
Seagull IV, can be used under a sink or on the countertop.
With 1,000 gallons (approximately) of useful filter life,
the mid-sized “strainer” can be expected to treat all the
water used in a kitchen.
Sears, Roebuck and Company
In the manuals for the two Sears water filters we sampled,
the firm recommends that if either unit has been
unused for over a day the element be flushed with a
brief flow of water before use . . . thereby extracting any
bacterial growth. The technique is effective but, of
course, does waste a portion of the filter’s treatment
capacity.
The Instapure by Water Pik is the smallest filter we
examined. It attaches to the end of a faucet and is
designed to be used at less than 1/2 GPM … although,
because of the device’s limited area of filtration, we’d be
inclined to keep the flow rate to about a quart a minute.
On the other hand, the Taste and Odor filter is a
large-capacity unit which — like the UTS Silverator
— can be used either to treat all the water at one
sink or to deliver cleansed liquid to a specific separate
tap.
In addition to its line of filters, Sears offers a free
water evaluation service — available by mail or through any
catalog store — which provides an analysis of your water
quality and offers suggestions for treatment techniques.
How Far Is Up?
Choosing a filtration system for your home depends for the most part upon what kind of treatment you
need and how much liquid you will want filtered. Units as
large as the BestWater can help eliminate ugly rings in
your bathtub as well as provide high-quality drinking
water. But if you’re looking only for something to give you
a better glass of water than you normally get from the tap,
the Instapure will do the job.
Of course, General Ecology’s devices — because
they’re officially classed as purifiers — can be
expected to provide exceptionally high-quality liquid . . .
and will even render unsafe water potable. And the American
Water Purification filters offer a viable mid-capacity,
mid-price solution to extracting nasty chemicals from your
drinking supply.
Each of the filters that we’ve examined proved to be a
well-put-together piece of equipment designed for a
particular purpose. Once you’ve determined what your needs
are — perhaps by having a water sample analyzed by
Sears or another laboratory — you can pick any one of
them with confidence.
