Common Drinking Water Contaminants
There are a number of problems that can affect the quality of the water you drink. Surprisingly, some contaminated water can look clean and clear at a glance. But just because water looks good, doesn't mean that it is.
The only way to be certain what's in your water is to have it tested. Water treatment professionals can perform on-site tests, direct your water sample to certified laboratories for more advanced testing and help you decipher the results. If you are supplied with water by a local water utility, you can request the results they've recorded from government mandated tests for a variety of contaminants.
While bad odors, unusual colors or metallic tastes usually indicate a drinking water problem, some go undetected. Lead is tasteless, odorless and colorless and can find its way into your water via soldered pipe connections. Lead-based solder was used in homes built as recently as the late 1980s.
Even though cities generally use chlorine to disinfect water to prevent illness and disease, chlorination is not a foolproof disinfection method. Unexpected outbreaks of certain microorganisms can still occur due to infrastructure problems and operator error. And although it's disinfected, city water may encounter contaminants once it leaves the treatment plant and travels through miles of distribution lines before it reaches your home.
The most common drinking water quality complaints, because they are easily identifiable and often leave water aesthetically unappealing, include:
- Chlorine Taste/Odor - generally caused by chlorine used to disinfect water supplies.
- Musty, Earthy, Fishy Tastes/Odors - caused by algae, molds and bacteria that live in water and can multiply within a home's plumbing system.
- Cloudiness/Turbidity - results from suspended particles or sediment.
- "Rotten Egg" Smell - comes from hydrogen sulfide in water.
- Color - linked to decaying organic matter (tannins) and metals such as iron.
- Metallic Taste or Smell - generally caused by metals such as iron and manganese.
Other problems that cannot be easily identified include:
- Chlorine Byproducts - created when chlorine reacts with other substances in water.
- Toxic Metals and Minerals - metals such as mercury, lead and arsenic.
- Volatile Organic Compounds (VOCs) - include commercial chemicals and pesticides.
- Microorganisms - include cysts, bacteria and viruses that can live in water.
Options for Improving Your Water
The good news is that there are a number of options available for improving your drinking water.
Carbon Filters
Activated carbon can reduce chlorine, VOCs, tastes, odors and, in some cases, lead. Carbon filters are available in a wide variety of sizes and styles, from small units that can be attached to the end of a faucet to in-line systems that must be connected to a home's plumbing. Filter cartridges must be changed regularly to ensure optimum contaminant reduction. Some systems eliminate guesswork by alerting you when a filter change is necessary.
Distillation Systems
Distillation systems boil water to reduce contaminants, then condense the steam that results and collect the water in a storage tank. Since certain substances don't vaporize, they don't rise with the steam. These units operate independently from a home's plumbing and are generally placed at the point of water use. Distillers can use a lot of energy, may radiate heat and must be cleaned regularly.
Ultraviolet Systems (UV)
UV systems inactivate microorganisms by exposing them to intense ultraviolet light but do not remove them. Since they can't remove other contaminants, UV systems are usually installed with other filters. They are ineffective with water that's cloudy, however, and constantly use electricity. Bulbs must be changed regularly for the systems to function properly.
Reverse Osmosis (RO) Systems
RO systems are recommended by the Centers for Disease Control as one of the most effective ways of protecting residential drinking water. They utilize a semipermeable membrane to reduce contaminants. When water is forced against the membrane, a portion of it passes through, while impurities are left behind to be carried away. Reverse osmosis is effective against dissolved salts, suspended solids, dissolved chemicals and a wide variety of other contaminants that cannot be seen by the naked eye. When choosing an RO system, look for a unit with a high recovery rate (recovery rate = amount of water produced divided by amount of water used). Generally, a rate of 25 percent or greater is considered efficient. Certain systems also employ a membrane rinse feature that cleans the membrane with the clean water produced by the system to prolong its life and ensure that it continues to produce only the best quality water.
Purifiers
In addition to the capabilities of a common reverse osmosis system, purifiers also remove harmful microorganisms that can cause waterborne disease by incorporating additional medical-grade filters. Legitimate purifiers have exceeded performance requirements outlined under NSF – P231, NSF International’s testing protocol developed using the USEPA’s Guide Standard and Protocol for Testing Microbiological Purifiers.
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