Testing Your Drinking Water

Posted: September 28, 2015

Homeowners using wells, springs or cisterns as their water supply should consider having their water tested routinely. Anyone served by public water suppliers who is considering water treatment equipment would benefit, too.

Seven Reasons to Test Your Drinking Water

Approximately one-third of Pennsylvania homes are served by private water supplies (wells, springs, or cisterns). Homeowners using this type of water supply should consider having it tested because:

  1. Private water supply testing is the voluntary responsibility of the homeowner. There are no government agencies or programs that routinely test private water systems.
  2. Surveys indicate that about half of the private water supplies have never been tested.
  3. Additional studies have found that about 50 percent of private water systems fail at least one drinking water standard.
  4. Many pollutants found in private water systems have no obvious symptoms and can only be detected through laboratory testing.
  5. Water testing is generally economical and convenient with many testing laboratories located throughout the state.
  6. Water testing provides vital information to document the quality of your drinking water.
  7. The only way to be certain that your water is safe to drink is to have the water tested periodically.

While a water supply can be tested for many things, such testing is very expensive and unnecessary. Instead, focus on testing on a few standard parameters along with tests related to nearby land uses.

Private water supplies should be tested every year for total coliform bacteria and E. coli bacteria. Coliform bacteria are a large group of bacteria common in soil and surface water. Large numbers of certain kinds of coliform bacteria can also be found in waste from humans and animals. Most types of coliform bacteria are harmless to humans, but some can cause mild illnesses and a few can lead to serious waterborne diseases. E. coli is a type of coliform bacteria found only in human or animal wastes. A positive E. coli result is much more serious than coliform bacteria alone because it indicates human or animal waste entering the water supply.

Every three years, drinking water should be tested for pH and total dissolved solids (TDS). These general tests provide an index to the quality of your drinking water. Water with a pH lower than 6.5 or greater than 8.5 can cause corrosion of lead and copper from household plumbing or bad tastes. The total dissolved solids content of drinking water should be below 500 milligrams per liter (mg/L), levels should not change much from one test to the next. Increases in the TDS of water could indicate pollution has occurred, warranting further testing. Additional testing should be done related to land uses occurring or expected to occur within sight of the home.

Obvious stains, tastes, or odors in water may prompt a homeowner to test their water. Many pollutants that cause obvious aesthetic problems are naturally occurring in groundwater, but may also come from land uses. While the symptoms make their presence obvious, testing by a certified laboratory is valuable to confirm the pollutant and provide information about the form and concentration of the pollutants needed to determine the best treatment options. A homeowner on public water who is considering water treatment equipment should also test their water before installing costly equipment. The Common Drinking Water Problems and Solutions fact sheet can help a homeowner diagnose problems.

Water tests should be performed by a certified water testing laboratory. Be cautious of water test results from an uncertified lab or from water treatment salespeople. The Pennsylvania Department of Environmental Protection (DEP) has a current listing of certified water testing laboratories. Water testing is also available through the Penn State Agricultural Analytical Laboratory. Drinking water test kits are available at participating county cooperative extension offices or directly from the Agricultural Analytical Services lab.

Most water samples are collected at the kitchen faucet. Treatment equipment will influence the results. If you are interested in determining the raw water quality from your well (as it emerges from the ground), collect a sample at the spigot on the pressure tank before the water enters any water treatment equipment or the home plumbing.

Do not take water samples to a laboratory that have been collected in used food or drink containers! Instead, obtain properly cleaned containers and instructions from the laboratory ahead of time. Follow sample collection instructions provided by the laboratory carefully to ensure an accurate test result.

Bacterial testing requires a sterile container and all chlorine must be cleared from the water system. Containers supplied by water testing labs will have a chemical present to remove any chlorine in the sample. Many labs recommend removing the aerator from the faucet and sterilizing the end of the faucet with a flame or rubbing alcohol before collecting the water sample. Allow the water to run for a few minutes, remove the cap from the bottle, taking care to avoid contaminating the cap or the bottle. Do not set the cap down on anything and do not touch the inside of the cap or the bottle with your hands. Fill the containers carefully and cap them securely. Keep the sample cool, and deliver it to the lab within 24 hours. Because of the time necessary for bacteria testing, most labs will not accept water samples on Fridays or before holidays.

More details about water testing are available in the Testing your drinking water fact sheet. Penn State Extension also offers Safe Water and Septic System Workshops. Visit the Water Resources website for more information on water testing, information on pollutants and solving water problems.

Contact Information

Diane Oleson, M.S.
  • Extension Educator, Renewable Natural Resources
Phone: 717-840-7429