Water Purification & Testing

Approximately 15 percent of Americans have private water supplies--wells, lakes and rivers--making them solely responsible for testing and purifying their drinking water. Most Americans, however, purchase water from their city's treated water supplies, which use increasingly antiquated treatment methods. Most bottled water is obtained from these same city water supplies and, like residential water, it isn't filtered. More and more, American consumers are seeking ways to guarantee the safety of their drinking water

History

• More than 50 percent of U.S. drinking water comes from groundwater, easily contaminated though improper dumping of wastewater and leaky septic tanks, underground storage and landfills all leaching their contents into the groundwater. Water, the universal solvent, also picks up any soluble contaminant it runs across. There are currently no regulations for disinfecting groundwater, and very few regulations overseeing the quality of private water supplies.

Significance

• Situations indicating a need for water testing include: suspected contamination from lead pipes or the need to find out if your water is bad enough to warrant investing in an expensive water filtration system. Well owners should test once a year, especially if wells, pipes or pumps have been replaced. Pregnant women and families with new babies should test drinking water, as should anyone who discovers tastes (bitter, salty, metallic, sour), smell (rotten egg, bleach, sewage) or colored staining concerns.

Types

• Well owners and homeowners acquiring water from wells, lakes and other untreated water supplies should consider these water tests. Microbial testing to look for bacteria (i.e. e. coli). Determine the effect of agricultural practices (i.e. pesticides) or septic tanks. Check for hard water and low pH levels. Tests for arsenic or radon in the soil, or leaching from local gas stations and chemical refineries.

Identification

• The more hazardous impurities have no taste, odor, staining or spotting linked to them and easily go unnoticed. These impurities can be divided into four categories: biological (bacteria, protozoa and viruses); inert chemicals (metals and physical features like alkalinity, pH and dissolved solids); organic chemicals; and radioactive contaminants (i.e. beta particles, photon emitters and radon).

Prevention/Solution

• Test results usually suggest the best purification methods. Some contaminants (color, odor or hardness) are best handled through point-of-entry treatments. Others should be managed through point-of-use strategies (reverse osmosis). For example, calcium causing hard water staining should be treated with a water softener then purified through reverse osmosis. Iron produces rusty stains and require a water softener and purification with whole-house iron reducing filters. Hydrogen sulfide generates a rotten egg odor, requiring purification with a whole-house iron reducing filter. Whole-house sediment filters purify water that appears gritty, muddy or dirty.

Expert Insight

• NASA engineers have also discovered other applications for the water purification system employed in the space shuttle program and onboard the International Space Station (ISS). The system uses iodine to purify the recycled water, significantly decreasing the need for water resupply missions, an expense that could quickly get out of hand. This system can be used in arid locations with limited water supplies, and has been applied successfully in Iraq.