How do I interpret the drinking water test results?
After your water has been tested at a state licensed laboratory, you will receive the test results in the mail. Each laboratory report looks different. However, for each substance that was tested, the amount of that substance found in the water sample should be reported. You can compare the amount detected in your water sample with the standard that is set by the U.S. Environmental Protection Agency’s (EPA) for public water supplies. Often times, the lab report will list the standard for each substance tested on the report. For more information on water quality standards, see the factsheet Drinking Water Standards and visit EPA’s website. Most substances in water are measured and reported as a concentration. Depending on the substance, the results will be reported as: Part per million (ppm) = milligram per liter of water = mg/L Part per billion (ppb) = microgram per liter of water = ug/L In addition, the lab will often report the minimum detection limit for each substance tested. This
