Other water quality authorities
There are many other regional, national, and international authorities that set standards for drinking water quality. Some of these are:
United States Environmental Protection Agency—Drinking Water Standards. Available at http://www.epa.gov/safewater/mcl.html
World Health Organization—Guidelines for Drinking Water Quality, 3rd Edition. Available at http://www.who.int/water_sanitation_health/dwq/gdwq3/en/index.html
Aesthetic vs Health-Related Guidelines
Often the guidelines listed in drinking water standards are separated into aesthetic concerns or health-related concerns. Some guidelines have both values.
Aesthetic guidelines
These are related to the consumer’s acceptance of the water for drinking and other domestic purposes and commonly include:
Health-related guidelines
Levels are based on the potential harmful effects to those drinking the water over long periods of time and at levels in excess of standards. Significant safety factors are often built in when setting standards.
*NB: For some guidelines—especially microbiological ones—even short-term exposure to water that does not meet standards may be unsafe.
Ground water should be chemically tested at least every five years to look for changes in quality and to determine if the aquifer has been contaminated.
*NB: When in doubt, test. If you think that there is a problem with the quality of your water, whether surface water or ground water, get it tested.
Those Nasty Bugs
Regular testing is necessary to ensure that potentially disease-causing microbes are not present in the water you supply, because severe health consequences may result.
Check with your local health authority for requirements regarding how often you must test your water. Compare your test results to government standards for the microbial quality of the water.
*NB: Any amount of coliform bacteria detected in the sample requires the water to be treated with the appropriate method.
Surface water sources must be treated regardless of coliform test results.