According to the Environmental Protection Agency, approximately 15 percent of Americans rely on private drinking water wells as their source of water at home. While public water is routinely tested and regulated for safety, private water is often not. If you use a private well, have your water tested for coliform bacteria and nitrates by a private water-testing lab. It will cost about $10 to $20 and will give you peace of mind. You can learn more and get a list of certification officers in your state at water.epa.gov.