Why should I test my well?
As
one of Wisconsin’s 700,000 private well owners or private well water
consumers, you’re using groundwater for doing your family’s laundry,
drinking, cooking, bathing and watering your garden. Municipalities are
required to test their water supplies regularly to ensure the water is safe
to drink. Since there is no requirement to test a private well except for
bacteria when it is first drilled or the pump is changed, you are
responsible for making sure your water is safe.
Most private wells provide a clean, safe supply of water; however,
contaminants can pollute private wells, and unfortunately you cannot see,
smell or taste most of them. Consequently, you should test your water on a
regular basis.
What tests should be done on my water?
Total Coliform Bacteria and E.coli
Coliform bacteria live in soil, on vegetation and in surface water.
Coliform bacteria found in the intestines of warm-blooded animals and their
feces are called E.coli. Some strains of coliform bacteria can survive for
long periods in soil and water and can be carried into well casings by
insects. Bacteria washed into the ground by rainwater or snowmelt are
usually filtered out as the water seeps through the soil, but they sometimes
enter water supplies through cracks in well casings, poorly sealed caps,
fractures in the underlying bedrock, and runoff into sinkholes. Coliform
bacteria are the most common contaminants found in private water systems.
A
1994 Wisconsin survey found them in 23% of the wells tested and E.coli in
2.4% of the wells. Most coliform bacteria do not cause illness, but indicate
a breach in the water system. However, since E.coli bacteria are found in
fecal material, they are often present with bacteria, viruses and parasites
that can cause flu-like symptoms such as nausea, vomiting, fever and
diarrhea.
Private wells should be tested at least once a year for bacteria, and can be
done at the La Crosse County Health Dept Lab.
Test again if there is a change in the taste, color, odor or appearance of
your water. The coliform test is one of the most important tests you should
have done on your well water. However, bacteria are only one of many
possible contaminants. A negative bacteria test is good news, but does not
mean your well is free of other contaminants.
Nitrate
Nitrate forms when nitrogen from fertilizers, animal wastes, septic systems,
municipal sewage sludge, decaying plants and other sources combines with
oxygenated water. In infants under six months of age, nitrate exposure can
cause a serious condition called methemoglobinemia or “blue-baby syndrome.”
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 oxygen available to the growing fetus. Test for nitrate if a pregnant
woman or infant will be drinking the water.
Everyone should have their water tested for nitrate at 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. Well owners should also test for nitrate regularly if
their well is located near an area where fertilizers are manufactured or
handled; or an animal feed lot or manure-storage area. In general, shallow
wells and wells with short or cracked casings have the highest risk of
contamination, however deep wells are also at risk in some areas.
A
1994 survey of Wisconsin wells found nitrate above the 10 parts per million
(ppm) standard in 6.5% of the wells.
How can I have my well tested?
The La Crosse County Health Department Laboratory is certified by the DNR,
EPA and Dept. of Agriculture and will test your water for bacteria and
nitrate (see cost for testing, below). We are located at 300 4th
St North, La Crosse, on the 2nd floor of the Health and Human
Services building. The lab will supply you with a water test kit (sterile
sample bottle, the instructions for collecting the sample, and sample
information form). When your test has been completed, the laboratory will
send you the results directly.
Private Well Testing Recommendations
|
Contaminant |
Which
wells or homes should be tested? |
How
often should I test? |
|
Coliform Bacteria |
Every well |
Test once a year, or when there is a change in taste, color or odor |
|
Nitrate |
All newly constructed wells or wells with no testing history
Wells within ¼ mile of fertilized fields or animal feed lots
Wells that had levels close to
10 ppm |
Two tests spaced 6 months apart
Test annually
Test before pregnancy and at time of birth |
What is the cost for testing?
The cost for testing your private well at the La Crosse County Health
Department Lab is $23.00 for the bacteria test and $22 for the nitrate test.
You do not have to be a La Crosse County resident to have your water
test done here.
Please call us at the County Health Department, 785-9872 with any questions
you have concerning well water testing. Whether you live in La Crosse
County or not, you have available the services of a Certified Health
Department Lab, staffed with experienced, professional Laboratory Analysts.
We’re here for you! |
