Testing to ensure water’s quality

By Jim Crawford

We go to the sink, turn the handle and out comes water. We cook with it, drink it, bathe in it and even use it to wash the car. Very rarely do we give the water coming from the faucet a second thought unless nothing comes out when we turn the handle or what comes out has a funny odor or color. What about the quality of the drinking water when it does not smell or appear orange?

For those of us that live in a town or are connected to rural water, the water quality is periodically checked and regularly monitored to ensure it is safe to drink. However, in rural Missouri many people still depend on a private well, cistern or spring for drinking water. Individual water supplies are private and water testing is usually not required by law. The exceptions are bacteria tests for new construction and some lenders require a test before they will proceed with a mortgage application.

Water testing and treatment can be expensive and time-consuming, but they are the only ways a home owner can ensure a safe and reliable water supply. Individuals using public water supplies pay for water testing and treatment as a part of their water bill. Individuals operating a private water system do not have this benefit and are responsible for the testing and treatment of their own water.

Testing water for every contaminant is possible but very expensive, impractical and not necessary. It is more important to test on a regular basis for a few indicators of contamination and to maintain a record of water quality. This helps to identify changes in the supply, contamination of the water source or deterioration of the water system. Good records of water quality are also important, should you need to prove that your water has been contaminated by some outside activity such as mining or waste disposal. In a private household water supply, the most important things to test for are: total coliform bacteria, nitrate, pH (acid or alkaline) level and total dissolved solids.

Total coliform bacteria is an indicator of bacteria. If this bacteria can live in your water supply other more harmful bacteria may also be present. Presence of any bacteria indicates a need for disinfection. This is the easiest of all tests to run and should be the absolute minimum test conducted each year. Sample bottles and instructions for collecting and submitting the sample can be obtained at your local health department. Many extension offices keep a supply of these test kits on hand.

Nitrates can occur naturally in the water supply or be the result of outside contaminants. They may be present because the water supply is in close proximity to human or animal waste sources or from excessive fertilizer use. Nitrate in water interferes with the body's capacity to absorb oxygen. High nitrate levels in water adversely affect infants and pregnant women. Infants are particularly susceptible-the condition is methemoglobinemia (blue baby disease). Adults are tolerant to much higher levels. The nitrate standard is established to protect infants less than one year old.

pH in water should be as close to neutral as possible. On a scale of 0 to 14, 7.0 would be considered neutral. Acid water with a pH less than 6.0 will be corrosive to plumbing and faucets, resulting in pitting or deposits. Low pH also tends to make metals and hardness minerals more soluble, which can dissolve metals from pipes and result in an unusual taste Water with a pH greater than 8.5 will have a bitter soda like taste.

High total dissolved solids (TDS) is an indicator of excessive concentrations of dissolved inorganic solids. Besides the water looking aesthetically undesirable, it can also affect the longevity of household appliances. Depending on the substance in excess, this can result in hard water, an objectionable taste (salty or bitter) or possibly a harmful health effect.

I receive many questions about hard water, which is a factor of total dissolved solids. Hard water is caused by calcium and magnesium dissolved in water. Hardness minerals react with soaps making them difficult to lather or cause them to form a scum, which is deposited on wash fixtures or clothes. Hard water can also cause an “oil slick” on coffee. These minerals in heated water will also precipitate as scale in appliances, pots, water heaters or pipes. Hard water has no known deleterious health effect.

Proper collection and handling of a water sample is critical for a meaningful water test. Contact your county health department or the certified laboratory you are going to use for specific directions in water testing and collection.

Jim Crawford is a field specialist in Agricultural Engineering for the University of Missouri Extension