Arsenic Fact Sheet
Arsenic (abbreviated As) is found naturally in some well water. Arsenic in water has no color, taste, or odor.
It must be measured by a laboratory test. Public water utilities must have their water tested for arsenic. You
can get the results from your water utility. If you have your own well, you can have the water tested. The
local health department or the state environmental health agency can provide a list of certified labs.
Information about arsenic in water can be found on the Internet at the US Environmental Protection Agency
website: www.epa.gov/safewater/arsenic.html.
There are two forms of arsenic: pentavalent arsenic (also called As(V), As(+5), and arsenate) and trivalent
arsenic (also called As(III), As(+3), and arsenite). In well water, arsenic may be pentavalent, trivalent, or a
combination of both. Special sampling procedures are needed for a lab to determine what type and how
much of each type of arsenic is in the water. Check with the labs in your area to see if they can provide this
type of service.
Reverse osmosis (RO) water treatment systems do not remove trivalent arsenic from water very well. RO
systems are very effective at removing pentavalent arsenic. A free chlorine residual will rapidly convert
trivalent arsenic to pentavalent arsenic. Other water treatment chemicals such as ozone and potassium
permanganate will also change trivalent arsenic to pentavalent arsenic. A combined chlorine residual (also
called chloramine) may not convert all the trivalent arsenic. If you get your water from a public water utility,
contact the utility to find out if free chlorine or combined chlorine is used in the water system.
The K-22155 system is designed to remove pentavalent arsenic. It will not convert trivalent arsenic to
pentavalent arsenic. The system was tested in a lab. Under testing conditions, the system reduced [0.30 mg/L
(ppm) or 0.050 mg/L (ppm)] pentavalent arsenic to 0.010 mg/L (ppm) (the US EPA Standard for drinking
water) or less. The performance of the system may be different at your installation. Have the treated water
tested for arsenic to check whether the system is working properly.
The RO component of the K-22155 system must be replaced annually to ensure that the system will continue
to remove pentavalent arsenic. The component identification and locations where you can purchase the
component are listed on kohler.com/filtration.
K-22155 system tested and certified by IAPMO R&T Lab and
IAPMO R&T against CSA B483.1, NSF/ANSI 42, 53, 58, 401,
and NSF Protocol P231 for specific performance claims as
verified and substantiated by test data. For more information,
refer to the Performance Data Sheet or visit kohler.com.
Kohler Co.
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1395432-2-B
