Utility and Private Well
Water Purification Systems
In the U.S., there are about 55,000 public water purification
systems. EPA mandates that these plants test for close to 80 contaminants. In 1996, 7% of
these plants, or 4,151, reported one or more violation of EPA standards for these
regulated contaminants. Less than 2%, or 681, did not use an EPA-required treatment
technique to eliminate certain pollutants.
Most community water purification systems obtain their water from surface sources, like
rivers, lakes, and reservoirs. These bodies, open to the environment, are susceptible to
pollution. Animal waste can contaminate surface sources with bacteria like Giardia and
Cryptosporidium. Industries can discharge their wastes into surface water, adding hazardous
organic contaminants to the source you may drink. Storm water drains can empty into rivers
and lakes with rainwater that's carrying gasoline, oil, and any number of hazardous and
bacterial wastes. Rainwater can also carry fertilizers and pesticides from fields into
streams, rivers, lakes, and reservoirs. Even train derailments and truck accidents that
cause tankers to spill their contents can contaminate surface sources.
Cryptosporidium in particular is difficult for treatment facilities to eliminate. Each
Cryptosporidium microorganism is covered by an outer shell, called a oocyst, that is
impervious to disinfection chemicals like chlorine. On rare occasions, these oocysts pass
untreated through treatment plants to your home.
In 1993, the City of Milwaukee experienced a severe Cryptosporidium outbreak. The parasite
passed through the treatment and disinfection process and caused over 400,000 people to
contract Cryptosporidiosis, a gastrointestinal disease that can be fatal to people with a
compromised immune system. More than 4,000 people were hospitalized, and more than 50
people died. The original source of contamination is uncertain.
Chlorine itself is another potentially harmful chemical. While it is vital to
disinfection, chlorine can bond with naturally occurring organic matter to form
potentially harmful substances, such as chloroform.
Other substances that can enter your drinking supply are rust, sediment, and even lead.
While flowing through distribution pipes from the treatment plant to your home, it can
pick up these pollutants after it's already been treated.
So how do you find out what's in your source? The best way is to call your community
system and ask for a quality analysis. You can compare the results to EPA's National
Primary Drinking Standards and National Secondary Standards to find out if it falls below
levels EPA thinks are safe for certain contaminants. As of 1999, your community system
will have to send you yearly reports with this information.
A note of caution: a test will only tell you what is in the liquid that day. Public
treatment plant failures can occur intermittently, and pollutants can be present after
these failures or after other events (e.g., after farm fertilizing periods, heavy rains,
or season changes).
Knowing what's in your source will help you select an OMNIFilter. If it is high in rust
and/or sediment, or if you wish to reduce odors and chlorine in all your faucets,
showerheads, and appliances, we recommend installing a Whole House filter. If you are
concerned about bacteria, lead, or volatile organic compounds (VOCs), we recommend
additionally installing an Undersink filter. Or if you just want great tasting
refreshment, we also recommend installing an Undersink filter.
People who use private wells are not immune from problems either.