Colors and Smells in Drinking Water
Colors and
Smells
Noticeable water problems tend to involve unusual colors,
smells, and tastes. Once identified, these aesthetically
displeasing elements can be eliminated using a variety of
different methods. Federal
guidelines are set up to monitor these aesthetic problems.
Taste and Odor
Since taste and odor work together it is often difficult to
distinguish the two. Common complaints include:
- Strong Chlorine taste or smell – Generally
this occurs when the water is treated at the water
treatment plant to disinfect it. The addition of chlorine
is used to kill off bacteria and other harmful
microorganisms (2). - Metallic taste – Some water systems
have a high mineral concentration giving the consumer a
salty or soda taste. In the case of Iron and Manganese, a strong metallic
taste is readily detected (1). - Rotten egg odor
– This is usually a result of decaying organic
deposits underground . As water flows through these
areas, hydrogen sulfide gas is picked up, and when this
water reaches the surface or comes out of the faucet, the
gas is released into the air. Hydrogen sulfide gas
produces the rotten egg odor, can be corrosive to
plumbing at high concentrations, and can tarnish silver
rapidly. In large enough quantities, it is toxic to
aquarium fish. As little as 0.5 PPM
(parts per million) can be tasted in drinking water
(1,2). - Musty or unnatural smells – These
smells are normally a result of organic matter or even
some pesticides in the water supply. Even very low
amounts can introduce unpleasant odors into the
water (1). - Turpentine taste or odor – This smell can
be a result of MTBE
contamination in your water. The odor threshold of MTBE
is fairly low, so even though you can smell it, the MTBE
is more than likely not at a level to cause harmful
effects.
Color
“Clean” water should be clear with no noticeable
color deposits. Common colors include:
- Red or Brown Color – A red, brown or
rusty color is generally indicative of iron or manganese in your water.
Disadvantages to iron in your water include stains in
sinks, or discolored laundry (1,2). - Yellow Color – This coloration
occurs in regions where the water has passed through
marshlands and then moved through peat soils. In the
United States, these conditions occur in the Southeast,
Northwest, New England, and Great Lakes regions. It is
more commonly found in surface water supplies and shallow
wells. Although the yellow color may be displeasing, it
presents no health hazard, as it is only small particles
suspended in the water (2). - Blue or Green Color – A green or
blue color is generally a result of copper in your water
supply, or copper pipes and corrosive water (1). The
copper can cause staining of your fixtures and your
laundry. Copper is regulated in drinking water by the EPA
at 1.3 PPM.
This is at a low enough concentration that the copper
cannot be tasted (the taste threshold is around 5 PPM).
Copper can become a problem if it is higher than 30
PPM in your water. Effects at this dose are vomiting,
diarrhea, and general gastrointestinal distress (3). If
you are using well water as your primary source of water,
and copper is a concern in your area, it would be to your
advantage to have your water tested for copper. - Cloudy White or Foamy – Cloudy water is
usually due to turbidity. Turbidity is caused by finely
divided particles in the water. When light hits the
water, it is scattered, giving a cloudy look to the
water. The particles may be of either organic or
inorganic nature. Neither one causes any harmful effects
to the body, although they can cause abrasions to pipes,
or possible staining of sinks (2).
References:
- Siouxland Home Page. A service of
Siouxland, an assembly of Midwestern organizations on the
Internet.
http://www.siouxlan.com/siouxlan/commercial/water/faq.html#tsO - Water Review Technical Brief, (1991)
Volume 6, No. 4; a publication of the Water Quality
Research Council. - Toxicological Profile for Copper. U.S.
Department of Health and Human Services. Agency for Toxic
Substances and Disease Registry. December 1990.
This page was prepared by S.L. Keyser, UCD EXTOXNET
FAQ Team
June 1997