News Release
* Taylor County Land Conservation Department * 925 Donald St., Room 104 * Medford, WI 54451 *
* 715/748-1469 * Fax: 715/748-4836 *
For Immediate Release
Date:
February 2, 2011
Contact:
Steve Oberle
County Conservationist
The State of Our Groundwater
Groundwater is referred to as the “Buried Treasure” in Taylor County. Conservation and protection of groundwater has
been our top natural resource concern and priority since it was identified as such in Taylor County’s first Land & Water
Resource Management Plan ten years ago. Taylor County citizens also recognize that groundwater provides critical
base flow to our creeks and streams, and headwaters for some of the main river systems in Central and Northcentral
Wisconsin (eg. Black, Little Black, Big Eau Pleine, Jump, Rib, Yellow, Mondeaux, Eau Claire, Spirit).
Groundwater Quantity
Despite a general abundance of groundwater in the state, there is a growing concern in Central and Northcentral
Wisconsin about the overall availability of good quality groundwater (in sufficient quantities) for municipal, industrial,
agricultural, and domestic use, and for adequate baseflow to our lakes, streams, springs, and wetlands. Available
groundwater in much of this part of the state is limited and comes mostly from fractures that exist in the bedrock where
well yields are relatively low. Limited groundwater storage potential in the crystalline bedrock aquifer and rapid surface
runoff deprive parts of the County of much water that otherwise would be available.
Based on previous groundwater studies in this region, yields of groundwater and natural streamflows during dry
seasons are too low to sustain large supplies for public or private wells. In general, soils of low permeability impede
downward seepage and promote rapid surface runoff and crystalline rock at or near the surface, generally covered by thin
deposits of low permeability, limit the groundwater recharge and storage potential. The result is a “water-poor area in a
water-rich State.”
In Taylor County, on average only 1 to 3 inches (of 32 inches) of precipitation annually enter the soil and eventually
become groundwater. The land surface in many areas is underlain by poorly productive, fractured crystalline rock which
in most cases yields sufficient groundwater for domestic wells but not for large water supply wells. Average well yields
(n > 1300) for Taylor County’s southern tier of townships within the near-surface crystalline rock region average less than
8 gallons per minute (gpm), with many wells yielding 3 gpm or less. The average depth to granite of these wells is about
63 feet, with many well logs showing granite (bedrock) less than 30 feet below the land surface.
Groundwater quantity problems in Taylor County have occurred naturally and from human activities. Natural shortages
of groundwater have occurred due to weather conditions (eg. drought) and hydrogeologic setting (eg. crystalline bedrock
aquifer with low relative yields). Consequently, water for public and industrial supplies is limited in a large part of Taylor
County. In some communities, public groundwater supplies are inadequate; in others they are barely adequate and
cannot sustain the increase for future needs. Groundwater quantity problems associated with human activities occur
when wells are spaced too closely together (which can lead to interference between wells) or the aquifer is over-pumped
or both.
The availability of groundwater in Taylor County and the surrounding region may also be affected by groundwater
quality. The presence of naturally-occurring substances in groundwater (eg. arsenic, iron, and manganese) or humancaused contamination (eg. leaking underground fuel storage tanks) has limited groundwater use in some areas of the
County. Approximately 15% of the wells tested in Taylor County over the past 10 years have indicated trace levels of
arsenic, with about 3% of wells tested having arsenic concentrations above the safe drinking water standard of 10 parts
per billion. High levels of iron and manganese can cause encrustation of wells and subsequent decreased well yields;
iron bacteria can form on the well casing to form a biofilm with similar results.
Groundwater Quality
Groundwater can become impaired in many ways and from many sources, both natural and human. As water soaks
into the ground, it dissolves minerals and gases from the soil and rock materials it encounters. These “naturally occurring”
minerals and gases may give water a particular taste, odor, or color but generally are not present in high enough
concentrations to pose a health risk.
Contamination of groundwater by human activity is a severe problem because contaminants travel unnoticed until
detected in a water supply. Once contaminated, groundwater is difficult and expensive to clean up. The pollutant
disperses in groundwater, is difficult to remove, and may persist for decades. In all cases, pollution prevention is simpler
and cheaper than trying to clean up contaminated groundwater.
The Taylor County UW-Extension office and Land Conservation Department have been conducting drinking water
testing programs since 1985. Water samples and test results collected through these programs provide a good picture of
the general quality of our groundwater. The results that follow are summarized from over 3000 “homeowner” water
samples and nearly 1300 “metals” samples collected between 1985 and 2010 (Figs. 1a, b, c).
Coliform Bacteria
A major problem found during drinking water testing each year is coliform bacteria. 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 carried 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 well caps, and
fractures in underlying bedrock.
Coliform bacteria are the most common contaminants found in private water supply wells. Drinking water samples
during 1985-2010 show that about 22% (nearly one-fourth) of water samples each year tests positive for coliform bacteria.
Coliform bacteria do not usually cause disease themselves, but they show that disease-causing bacteria might be
present. When disease-causing bacteria are present, a variety of “flu-like” symptoms such as nausea, vomiting, fever,
diarrhea, and even hepatitis may result from drinking the water. However, sometimes there are no symptoms. People
should suspect coliform bacteria problems especially if their water changes color or becomes cloudy after heavy rain or
snowmelt.
Unfortunately, there are many possible reasons for bacteria problems. Some wells may need simple, inexpensive
repairs, while others may need major work or even replacement. It’s important to get a copy of the Well Construction
Report for your well, if at all possible. Knowing the well depth, the amount of casing that lines the inside of the well, and
the type of rocks and soil that were drilled through will help know if the well likely has a minor defect or needs major work
or replacement. If a well has tested positive for coliform bacteria in the past, resampling the well is always recommended
before undertaking any expensive work on it. Many coliform bacteria problems can be avoided or solved by:
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Choose a proper sampling tap, such as the brass faucet near the pressure tank
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Clean up pet waste within 25 feet of the well, and keep pets away from the well
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Ensure that the well cap has an air vent, and that the vent is not blocked by small debris
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Check that the wiring for the well is in a good conduit
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Inspect the well cap for signs that insects have taken up residence, and clean them out
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Install a vermin-proof well cap
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Disinfect the well according to appropriate procedures after fixing any problems found
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Properly abandon or replace old dug wells with wells of modern construction
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Ensure that surface water does not pond near or around the well casing
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Keep flowers and plants that may attract insects away from the well casing
Nitrate
Nitrate forms when nitrogen from fertilizers, animal wastes, septic systems, municipal sewage sludge, soil organic
matter, decaying plants and other sources combines with oxygenated water. High nitrate water is unsafe for pregnant or
lactating females to drink and for infants less than six months, since it can interfere with the oxygen-carrying ability of a
baby’s blood. Nitrate may also cause birth defects in the unborn, or miscarriages. In infants under six months of age,
nitrate exposure can cause a serious condition called methemoglobinemia or “blue-baby syndrome.”
During 1985-2010, an annual average of only about 3% of the wells had unsafe nitrate (above 10 parts per million).
Although this is good news from a health perspective, nearly 20% (one-fifth) of the wells tested had nitrate levels above
natural background levels. Private well owners are encouraged to test their water for coliform bacteria and nitrate at least
once every 15 months.
Phosphorus
Elevated concentrations of nitrogen and phosphorus, nutrients that can negatively impact our lakes, streams,
groundwater, and human health, have remained the same or increased across the nation since the early 1990’s.
According to a new national study by the U.S. Geological Survey, widespread concentrations of nitrogen and phosphorus
remain two to ten times greater than levels recommended to protect aquatic life. Phosphorus—an essential nutrient for
plant growth—is a common ingredient in many lawn and garden fertilizers. However, the same phosphorus that helps
keep lawns green is also the primary nutrient that turns lakes green with algae. Algae blooms can turn lakes into a thick,
smelly green soup that is undesirable for swimming and other recreation. Too much algae clouds water and blocks
sunlight from reaching aquatic plants; it also lowers the oxygen levels in the water which can cause fish kills.
Fertilizers, leaves, grass clippings, eroded soil, and animal waste are all sources of nutrients, including phosphorus.
Phosphorus is main nutrient that drives eutrophication (premature aging) in most lakes. Relatively small amounts of
phosphorus can cause water quality declines. A concentration of 25 parts per billion (.025 parts per million) of
phosphorus in water can promote excessive algae growth in lakes.
Phosphorus concentrations in Taylor County drinking water samples have been measured for the last 10 years and, in
many cases, indicate very high levels of phosphorus in our groundwater. Phosphorus concentrations measured in
drinking water samples collected between 2001 and 2010, in most cases, range from less than one-tenth of a part per
million (ppm) to over 3 ppm (Figure 2). Although these phosphorus concentrations in our groundwater likely do not cause
significant health issues, they do help explain algae blooms and other water quality issues connected with elevated
phosphorus levels in our surface waters. Full accounting and assessment of groundwater contributions of nutrients (eg.
phosphorus) to surface water is a critical step in developing management strategies to meet water quality goals for
protection of drinking water supplies and aquatic life.
Hardness
Drinking water hardness is an aesthetic issue and data show that Taylor County groundwater is relatively soft – slightly
over 20% (one-fifth) of the samples each year come back above the ideal range for hardness. Hardness in drinking water
is caused mostly by dissolved calcium and magnesium, primarily the result of dissolved limestone or dolomite from soil
and rock materials. Hard water is beneficial to human health but can cause some lime buildup in plumbing and water
heaters. Hardness in drinking water should always be tested prior to conditioning or softening your water. While in some
cases a water softener may be an effective alternative for iron treatment, in cases of naturally or relatively soft water,
alternative iron treatment methods (eg. iron filter) may be more economical in the long run.
Chloride
In most areas of Wisconsin, chloride in groundwater is naturally less than 10 parts per million. Some higher
concentrations in limestone and sandstone aquifers in eastern Wisconsin may also be natural. Higher concentrations,
similar to those found in Taylor County, usually indicate groundwater contamination by septic systems, road salt, fertilizer,
animal waste, or other wastes. From 1985 – 2010, annually about 34% (one-third) of the wells tested had chloride levels
above the expected naturally occurring level. Water with high chloride concentrations may also have high sodium content
and may speed up corrosion in plumbing (just as road salt does to your vehicle).
Corrosivity
The corrosivity or saturation index was also measured in Taylor County drinking water samples. There is no health
standard for corrosivity; however, values less than zero are considered corrosive to some degree. In Taylor County,
about 27% of our samples are corrosive to some degree each year. Symptoms of corrosive water include pinhole leaks in
copper pipes or green stains on plumbing fixtures. With corrosive water; lead, copper, and zinc from plumbing, fixtures,
and solder joints can also dissolve into drinking water at unsafe levels.
Metals
Almost 80% of the elements found on earth are classified as metals. Some elements such as copper, iron, and lead
we easily identify as metals. But the metals group also includes such common elements as sodium, calcium, zinc,
manganese, and arsenic, to name a few. Some metals are essential to humans; others have no health benefits or are
toxic. Other metals are essential to human health in small amounts but toxic at higher concentrations. Metals and
minerals included in our annual drinking water “metals” test package can be divided into three categories:
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Beneficial to health, not normally found in drinking water in toxic amounts (calcium, magnesium, iron,
potassium)
Essential to health in small amounts, may be toxic at higher concentrations (copper, manganese,
sodium, sulfate, zinc)
Toxic, no known benefit (arsenic, lead)
Annually, about 6% of water samples contained unsafe lead levels, an average of 5% had unsafe copper levels, and
less than 4% had unsafe zinc levels. Lead, copper, and zinc may dissolve into water from household plumbing, fixtures,
and solder joints. These samples were collected first thing in the morning after the water had not been used all night.
Running the water for a minute or two after periods of non-use often brings these metal concentrations in drinking water
down to safe levels.
Sodium
Sodium is a metal that is essential to health in small amounts, but can cause some problems at higher levels. The
natural level of sodium in Wisconsin groundwater is about 5 to 10 parts per million, except in some areas of eastern
Wisconsin where groundwater is drawn from deep sandstone layers. Sodium is often found at elevated levels in Taylor
County groundwater from road salt or septic system effluent.
Sodium levels in drinking water samples were above the health advisory level of 30 parts per million in 35% (over onethird) of the wells tested annually. The annual average number of wells testing above a background level of 10 parts per
million is about 45% (nearly one-half). This is a disturbing trend not only from the standpoint of health risks associated
with elevated sodium, but also from the point of view that sodium may be an indicator of other contaminants in our
groundwater – contaminants that may have their origins from road or highway runoff or septic system effluent.
Iron and Manganese
About 34% (one-third) of drinking water samples had iron and manganese concentrations above the levels likely to
cause color changes in drinking water or staining of laundry and plumbing fixtures (Figs. 3 and 4). In the case of iron,
levels over .3 parts per million often cause taste and a discoloration of water and clothes washed in it. Water with .05
parts per million or higher manganese would likely cause significant black precipitates in toilets and clothing. Iron and
manganese can occur where groundwater is low in oxygen, such as areas of wet or organic soils (near lakes, wetlands, or
marshy areas). Taste and odor problems associated with iron can be made worse by iron bacteria that, in some cases,
can be controlled by well disinfection.
In some cases, excessive iron and manganese intake from drinking water can cause health-related problems. There is
currently a health advisory level of 0.3 ppm for manganese in drinking water. Health professional suggest that infants and
people who drink more than eight cups of water per day and have a liver disease should avoid drinking water that is
above the health advisory level. Also, excess iron intake can cause diabetes and heart disease, while many years of
exposure to high levels of manganese can cause harm to the central nervous system, and in some cases, a disorder
similar to Parkinson’s disease can result. This type of effect is most likely to occur in the elderly.
Arsenic
One of the most serious potential health threats in Taylor County drinking water is arsenic. Since the lab that analyzes
our samples just started measuring arsenic in 2000, there is limited data available to summarize and identify any longterm trends. From 2000 to 2010, about 15% of wells tested had a detectable level of arsenic (Figure 5). On an annual
basis, about 3% of the wells tested are above the Wisconsin safe drinking water standard (10 parts per billion). Samples
from the same well over a period of two or more years, in some cases, indicate that arsenic concentrations can increase
with time and with additional draw-down (pumping). Seasonal variations in groundwater recharge may also affect arsenic
concentrations over time. These trends suggest the necessity for Taylor County residents with private wells to monitor
their drinking water arsenic level on a regular basis. Arsenic has no known benefit to humans and long-term exposure to
elevated levels of arsenic is known to increase risks of skin, bladder, lung, liver, colon, and kidney cancer.
Testing Your Water
Taylor County residents use groundwater for doing laundry, drinking, cooking, bathing, and watering, among other
things. Municipalities with public water systems 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), residents with private wells are responsible for making sure their own water is safe for themselves and their
families. As we have learned in all too many cases, safe drinking water should not be taken for granted.
Most private wells provide a clean, safe supply of water. However, as we have noted many contaminants can pollute
private wells, and unfortunately you cannot see, smell, or taste most of them. Because of this, it is advised that residents
with private wells test their drinking water regularly, about every fifteen months for coliform bacteria and nitrate. This is to
ensure that you are sampling at a different time of the year, which allows you to detect seasonal variations in your drinking
water quality.
Although the drinking water test results summarized above give us a good general picture of groundwater quality in
Taylor County, these tests do not measure all potential biological or chemical contaminants in our groundwater. The
decision on what to test your water for should be based on the types of land uses near your well and any potential
contaminants you are concerned about.
Groundwater Conservation and Protection
There are many things that you can do to help conserve and protect groundwater. The first step is to examine your
own actions and how they may or may not contribute to excessive water use or groundwater contamination. Why should
homeowners on individual wells be concerned about water conservation? For a start, conservation saves money. The
less water you use in your household, the less time your water pump and water heater operate, which reduces your
energy bill. Excessive pumping can lower groundwater levels. Pumping from deeper in the aquifer uses more energy.
Where there are several wells in the same aquifer, excessive use in one well can cause problems in adjacent wells.
Not only is groundwater of importance as a supply source for homes and businesses, but groundwater also supplies
many streams, lakes, wetlands, and ponds. Excessive groundwater use can therefore have a detrimental effect on the
natural environment.
Even though water is a renewable resource, it is advisable not to withdraw and consume more than can naturally be
replenished. Many communities across the country are trying to educate people on the importance of water conservation
and the concept of sustainability in order to prevent water shortages and to avoid taking more drastic measures such as
water rationing. Here are some tips that you can follow to reduce your daily water use and your monthly energy bill:
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Fix leaky faucets and valves (a slow leak can waste thousands of gallons per year)
Install water efficient appliances and fixtures (new clothes washers use less than half the water of older
models)
Operate the dishwasher and wash machine with full loads
Keep a pitcher of water in the refrigerator to avoid running that tap water until it is cold
Place a brick or plastic jug filled with sand in the toilet tank to take up space (unless you already have a
low-flush toilet)
Insulate water heaters and pipes (this reduces the amount of water needed to run before hot water
delivery)
Turn off the faucet when brushing teeth, shaving, or washing dishes
Take shorter showers and install low-flow shower heads
Water lawns and gardens in the evening or early morning to avoid excessive evaporation and moisture
loss
Minimize use of kitchen sink garbage disposal units (these require large amounts of water to work
properly)
Use a broom, not a hose, to clean driveways and sidewalks
Do not run the hose while washing your vehicle
Put a layer of mulch around trees, shrubs, and plants (this will slow down evaporation)
Set lawn mower blades one notch higher (longer grass means less evaporation)
Remember – pollution prevention is the key to keeping our groundwater safe and free from contamination! Everyday
activities can affect groundwater quality. Think about the ways you use water at home. A little common sense will go a
long way toward keeping our groundwater clean. Groundwater protection is critical to ensuring safe drinking water
supplies, especially in areas where a majority of the drinking water is supplied from private wells. As individuals and
communities become aware of both the potential health risks and economic effects of groundwater contamination, we
would be wise to look increasingly toward preventive efforts in our planning and practice. Taylor County residents wanting
to test their water or having questions about groundwater or drinking water should contact the Land Conservation
Department at 748-1469 or visit the office at 925 Donald Street, Room 104, Medford.
**End**