Homeowner Testing Needs
What Testing Should I Consider for my Private Well?
The universe of potential environmental contaminants is quite expansive, and testing for all possible contaminants can be a quite expensive proposition. Therefore, we offer this information to help you narrow down the most critical well testing to be considered.
The first consideration when you feel your water tastes or smells "funny" is whether or not your water is supplied by a municipality, or some other small system, or whether your source is a private well. If your water is not supplied by a private well, then state -regulated testing must be performed, and before investing in testing on your own, you should review testing records from your water supplier. This is available in the form of a "Consumer Confidence Report". You can access the Consumer Confidence Reports for any water system from the Department's website.
Please note that many consumers report concerns because their municipally-supplied water either smells or tastes like chlorine. This typically prompts the homeowner to contact the municipal waterworks to request that the chlorination be reduced. Actually, chlorine used for disinfection is odorless and tasteless. If you smell or taste something like chlorine, it's more likely due to chloramines (a smell more like that associated with indoor pools or hot tubs). Chloramines are formed by reaction of chlorine with ammonia (from nitrogen sources in the water) and the presence of chloramines indicates that the level of chlorine in the water is insufficient for proper disinfection, and the chlorine level to the system should actually be increased!
Common Contaminants of Concern
Bacteria (Coliform)
Private wells should be tested at least once a year for bacteria, by a laboratory that performs an E.coli test when total coliform are present. Test again if there is change in the taste, color, odor or appearance of your water. Coliform bacteria are the most common contaminants found in private water systems.
To ensure protection from bacteria, make sure that your well cap and casing are propoerly sealed with no cracks or leaks. It has been reported that the presence of earwigs in private well systems can lead to high bacteria counts because of the bacteria harbored in the earwigs' stomachs.
Other Nuisance bacteria
Iron and sulfur bacteria may also be present in wellwater. Although these organisms do not pose a health threat, they can affect the taste, odor and appearance of water. You may have a nuisance bacteria problem if your water has a rotten egg smell or if you notice slime in the toilet tank. If you suspect a nuisance bacteria problem, try disinfecting the well andwater system before testing for iron or sulfur bacteria.
Nitrate
In infants under six months of age, nitrate exposure can cause a serious condition called methemoglobinemia --or “blue-baby syndrome”--in which the nitrate binds with the bloods hemoglobin, thereby preventing the blood from being re-oxygenated. Infants with this condition need immediate medical care because it can lead to coma and death. Nitrate taken in by pregnant women may reduce the amount of oxygenavailable to the growing fetus. Test for nitrate if a pregnant woman or infant will be drinking the water. There have also been reported cases of this illness in people with compromised immune systems that drank water with high levels of nitrate. Everyone should have their water tested for nitrateat least once. If you live in an area within 1/4 mile of a corn, soybean or vegetable field, you should test your water for nitrate regularly.
Lead
Lead was a component of plumbing solder that was used in homes with copper plumbing installed before 1985. It has also been used in brass fixures. When water is naturally soft or acidic, lead can leach from solder or brass into drinking water. Wells located near existing or former cherry orchards in Door County may also contain lead.
Copper
Copper is present in plumbing lines in most house-holds. Homes that have new copper plumbing or a naturally-soft water supply are more likely to have copper-contaminated water.
Arsenic
If you live in Brown, Outagamie or Winnebago County, contact your DNR drinking water and groundwater specialist to find out whether your well needs to be tested. An arsenic test may be advised if you live near a landfill that received paint or electronic components.
Pesticides
If your well is located within 1/4 mile of a corn, soybean or vegetable field, you should test your wellwater for pesticides. You should also consider a pesticide test if your well is within 1/4 mile of an area where pesticides are manufactured, stored, mixed or loaded into application equipment.
The most common pesticide found in Wisconsin’s groundwater is atrazine, which is used to control weeds in corn crops. An atrazine “screen”, which costs around $25, is generally a good first indicator of pesticide contamination in wells that are located near corn fields.
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