Water Testing & Interpretation

Posted: April 13, 2011

What purpose does water testing serve? Drinking water standards have been established for public water supplies. These standards were set to protect human health and avoid nuisance problems such as iron staining. Periodic testing by the public supplier insures that the water supply is safe for human use at all times. The only way to insure that a private water supply meets the drinking water standards is to test it. One way of justifying the cost of testing is to compare it with the price of a visit to the doctor. If testing can prevent a doctor’s visit, it will be cost effective not to mention the benefit derived from not getting sick.When water testing is decided upon, what tests should be done? This question can be difficult to answer. There are three basic ways of looking at the question.
What's in Your Water?

What's in Your Water?

First, there is the method of symptoms. Does the use of the water cause any symptoms either healthwise or in appearance? If the water is suspected of causing digestive tract problems then a test for total coliform bacteria is in order. If the water is causing red stains in the sink, then a test for iron may be in order.
Second, there is the method of testing based on knowledge of problems common to the region. Acid water is a common problem in Adams County.  This may result in corrosion of plumbing systems and can lead to problems with dissolved metals such as iron, lead, or manganese. In this methodology, the test is designed for contaminants known to be common in the area.
Third, there is the method of threats. Look at the contributing area for your well. What sorts of contaminants could originate in that area? Test for those identified.
In the absence of other guidance a bacteria test should be done once a year. In addition a test for pH and total dissolved solids is recommended every other year. If fertilizer is used on your yard or other surrounding areas and there are infants in the home a test for nitrate should be done at least once.

The Results are in.....
The total coliform test indicates the water is satisfactory when the coliform count is less than one per 100 ml. Coliform bacteria live in the intestines of people and warm blooded animals. Some members of the coliform group are also found in the topsoil. While the coliform bacteria themselves do not cause disease their presence indicates disease causing organisms could be present.
When the test is unsatisfactory examine the water supply for possible entry of surface water. Check the well casing for cracks or rust holes. Examine the condition of the seal where the water line goes through the casing. Correct  any problems you discover, then shock chlorinate the well and retest the water a week or more later. If contamination persists there are three options available. Purchase water for drinking and cooking; develop a different water source; or, treat the present source. Ultraviolet light and chlorination are two suggested methods of bacteriological treatment.
Nitrate                                                                                                                                                                  The presence of more than 10 milligrams per liter or 10 parts per million of nitrate nitrogen can cause methemoglobinemia (blue baby syndrome) in infants. This disease occurs in infants less than six months old. It is caused by bacteria in the stomach. These bacteria change nitrate to nitrite which mimics oxygen. The blood contains hemoglobin which carries oxygen from the lungs to the tissues. The nitrite molecule attaches to the hemoglobin molecule in place of the oxygen. The hemoglobin-nitrite combination is then called methemoglobin giving the illness its name. The blood in this condition is unable to supply the needed oxygen and the baby begins to turn blue from lack of oxygen. Once the infant's stomach begins producing acid the bacteria cannot survive and there is no further danger. The two basic types of treatment to remove nitrates from water are ion exchange and demineralization. An alternative is  to buy bottled water or use water from another source for infants under six months of age.
Lead                                                                                                                                                                      Lead is not received from drinking water only. In fact water is not normally the major source of exposure to lead. However keeping lead at a low level in drinking water helps keep the overall exposure to lead within acceptable limits. The maximum concentration permitted in drinking water is 0.015 milligrams per liter or 0.015 PPM. Exposure to high levels of lead can lead to brain and nerve damage especially in young children. The source of lead is normally the plumbing system through which the water passes. Two ways to deal with high lead levels are, remove lead solder from the plumbing system, or, run the water a few minutes until fresh water is coming out the tap.
pH                                                                                                                                                                       A pH of 7.0 indicates the neutral condition (neither acid nor alkaline) of water. Water having a pH lower than 6.5 may dissolve some of the metals (lead, cadmium and zinc) used in the plumbing and thus add metals to your water. Acid water does not cause problems with plastic plumbing. Each unit of change in pH represents a tenfold change in acidity. For example water with a pH of 6.0 is 10 times more acidic than water with a pH of 7 while water with a pH of 5 is 100 times more acidic than water with a pH of 7. Acceptable pH levels are 6.5 to 8.5.
Low pH can be corrected with a neutralizing filter or by feeding soda ash into the water line. The neutralizing filter will add some hardness to the water. The soda ash does not add hardness; however it adds some sodium to the water.
TDS                                                                                                                                                                            High total dissolved solids may in some cases cause the water to have a noticeable taste. The nature of the taste depends on the minerals present. High total dissolved solids are the result of the water being in contact with rocks in the aquifer for a long time on the way to your well. The recommended maximum level of total dissolved solids is 500 mg/l.