In many rural areas, homes depend on wells to supply for their needs. While the Environmental Protection Agency requires that public supplies be tested to ensure they meet certain standards, such tests are not generally required for private wells in the United States. Well water testing ensures a home's supply is safe for the family to consume.

Several tests are used as determiners of the quality of the supply along with the presence of contaminates. Indicator strains of bacteria and chemicals, which do not necessarily cause illness, are checked. Their presence indicates the supply may have been contaminated by germs, including those in raw sewage that can cause illness.

One of the greatest concerns is contamination by bacteria often found in the digestive systems of humans and other warm blooded animals. For example, the lab may perform a total coliform count to indicate the number of such bacteria in the sample size. If such counts are high, there is a larger chance of the presence of other bacteria, which can cause harm, being present in the sample.

A more specific bacterial test is for Escherichia coli, often abbreviated as E. Coli. A positive test for E. Coli indicates fecal contamination of wells. While the indicator form of E. Coli is generally harmless, the germs that contaminate wells when it is present may cause health problems including hepatitis, dysentery or diarrhea. Owners should note the presence of the indicator E. Coli is not the same as the more dangerous strain of the bacteria that often makes the news.

In order to test the level of acids or bases in the sample, the lab often tests the pH. This level affects both taste and looks of the water. Neutral samples have a pH of 7. If this number is too high or too low, heavy metals can leach out of the pipes into the drinking supply. In addition to damaging the pipes, continuing to drink the liquid could make one ill.

While nitrates are found in many types of food, they should not be in your drinking supply as they can make you and others sick. Sources of nitrates include animal waste, septic tanks, flooded sewers and polluted storm water. Fertilizers and runoff from farming can also affect the well's quality. The natural geographic features surrounding wells can increase nitrate levels.

In some regions, volatile organic compounds from fuel or industrial pollution contaminate wells. The exact VOCs for which one should test depend on the location in which one lives. If they are a problem in your region, the local health department can tell you the tests to have completed.

Specific locations may also have specific healthy concerns. Chemicals, including heavy metals may be a problem locally. In other areas, wells should be tested for specific bacteria in order to ensure the home has a safe supply.

Generally, homeowners should submit samples to a lab for well water testing annually. Samples should also be submitted when there is a difference in quality of if land disturbances have occurred. With proper testing, you ensure your supply remains healthy for the family.