What is Nitrate
This test measures the amount of nitrate-nitrogen in your well. Nitrate is a form of
nitrogen, commonly found in agricultural and lawn fertilizer,
that easily dissolves in water. It is also formed when waste materials such as manure or
septic effluent decompose. The natural level of nitrate in Wisconsin's groundwater is
less than 1 mg/L. Levels greater than this suggest groundwater has been impacted by
various land-use practices.
Why Test for Nitrate
Nitrate is an important test for determining the safety of well water for drinking. Nitrate is a test that
allows us to understand the influence of human activities on well water quality. Because it moves
can come from a variety of sources and moves easily through soil, it serves as a useful indicator of certain land-use activities.
An annual nitrate test is useful for better understanding whether water quality is getting better, worse, or staying
the same with respect to certain land-uses (see Sources).
Interpreting Nitrate-Nitrogen Concentrations
Health Effects of Nitrate in Drinking Water
Ways to reduce nitrate in your drinking water
One way to reduce nitrate is to install a water treatment device approved for removal of nitrate;
testing is the only way to make sure these devices are properly functioning
Point-of-use devices treat enough water for drinking and cooking needs
- Reverse Osmosis
- Distillation
Point-of-entry systems treat all water distributed throughout the house
Additionally, you may want to investigate the potential that drilling a new well or well reconstruction
may provide water with safe nitrate levels
Sources of Nitrate
- Agricultural Fertilizers
- Manure and other biosolids
- Septic Systems
- Lawn Fertilizers
Strategies to reduce nitrate in groundwater
- Applying fertilizer at the right rate, time, source, place will maximize
profitability and minimize excessive losses of nitrogen to groundwater; additional
practices may be needed to improve water quality in areas with susceptible soils and geology
- You may not need as much nitrogen fertilizer as you think, conduct your own on-farm rate trials
to develop customized fertilizer response curves for your farm
- Utilize conservation incentive programs to take marginal land or underperforming
parts of fields out of production
- Diversify cropping systems to include less nitrogen intensive crops in the rotation
- Explore and experiment with the use of cover crops, perennial cropping systems, or
managed grazing to reduce nitrate losses to groundwater
What is Chloride
In most areas of Wisconsin, chloride concentrations are naturally low
(usually less than 15 mg/L). Higher concentrations may serve as an indication that
the groundwater supplied to your well has been impacted by various human activities.
Why Test for Chloride
Chloride is a test that allows us to understand the influence of human activities on well water quality.
Measuring chloride concentrations in your well water will allow us to better understand whether well
water quality is getting better, worse, or staying the same with respect to certain land-uses (see Sources).
Interpreting Chloride Concentrations
Chloride is not toxic at typical concentrations found in groundwater. Unusually high
concentrations of chloride (greater than 150 mg/L) are often associated with road salt and may be related to nearby
parking lots or road culverts where meltwater from winter deicing activities often accumulates.
Water with concentrations greater than 250 mg/L are likely to contain elevated sodium and are sometimes
associated with a salty taste; water is also more likely to be corrosive to certain metals.
Sources of Chloride
- Agricultural Fertilizers (chloride is a companion ion of potash fertilizers)
- Manure and other biosolids
- Septic Systems
- Road Salt
What is Alkalinity
Alkalinity is a measure of water's ability to neutralize acids. Alkalinity is associated with carbonate
minerals and is commonly found in areas where groundwater is stored or transported in
carbonate aquifers which occur in parts of Green County.
Why Test for Alkalinity
Because alkalinity is related to the rocks and soils that water flows through on its way to a
well, we would expect alkalinity concentrations to be fairly stable from year to year. Any changes observed in alkalinity
concentrations may help us better understand the influence of climate variability
on well water quality on an individual well, or make sense of broader water quality results from Green County.
Particularly in wells that are uninfluenced by human activity,
Alkalinity concentrations may help us better understand which wells are accessing younger water that may be
more vulnerable or prone to contamination.
Interpreting Alkalinity Concentrations
There are no health concerns associated with having alkalinity in water.
Alkalinity should be roughly 75-100% of the total hardness value in an unsoftened sample.
Water with low levels of alkalinity (less than 150 mg/L) is more likely to be corrosive.
High alkalinity water (greater than 200 mg/L), may contribute to scale formation. If total
hardness is half or less than the alkalinity result, it likely indicates that your water has passed
through a water softener. If alkalinity is significantly less than total hardness, it be related to
elevated levels of chloride or nitrate in your water sample.
What is Total Hardness
The hardness test measures the amount of calcium and mangnesium in water. Calcium and
magnesium are essential nutrients, which generally come from naturally sources of these elements in rock and soils.
The amount present in drinking water is generally not a significant source of these nutrients compared with a health diet.
Why Test for Total Hardness
Because total hardness is related to the rocks and soils that water flows through on its way to a
well, we would expect total hardness concentrations to be fairly stable from year to year. Any changes observed in total hardness
concentrations may help us better understand the influence of climate variability
on well water quality on an individual well. Because hardness concentrations have been shown to increase when nitrate and/or chloride
increase, the total hardness test is a good complement to other tests.
Interpreting Total Hardness Concentrations
There are no health concerns associated with having total hardness in your water, however too much or too little hardness can be associated
with various aesthetic issues that can impact plumbing and other functions.
Hard Water:
Water with a total hardness value greater than 200 mgL is considered hard water.
Hard water can cause lime buildup (scaling) in pipes and water heaters. Elements responsible for water hardness can also react with soap
decreasing its cleaning ability, can cause buildup of soap scum, and/or graying of white laundry over time.
Some people that use hard water for showering may notice problems with dry skin.
If you are experiencing problems with hard water:
Consider softening water using a water softener.
Water softeners remove calcium and magnesium and replace those elements with a different cation (usually sodium).
Many people choose not to soften the cold-water tap used for drinking/cooking and the outdoor faucet used for yard watering.
Soft Water:
Water with a total hardness concentration less than 150 mg/L is considered soft. Water with too little hardness
is often associated with corrosive water, which can be problematic for households with copper plumbing or other metal components of a
plumbing system. Please note: Total Hardness values less than 50 would be rare for Green County, if your water reported less than 50 mg/L of Total
Hardness it likely represents softened or partially softened water.
If you are experiencing problems with soft water or corrosion of household plumbing:
You may want to consider a water treatment device
(called a neutralizer) designed to make water less corrosive. Newer homes with plastic plumbing generally don't need to be as concerned with corrosive water
with respect to the plumbing.
Ideal:
Water with total hardness between 150-200 mg/L is generally an ideal range of water hardness because there are enough ions to
protect against corrosion, but not too many that they contribute to scale formation. While it is a personal preference, households
with hardness in this range generally don't require additional treatment.
Note: the water softening industry measures hardness in grains per gallon. 1 grain per gallon = 17.1 mg/L as CaCO3
Sources of Total Hardness
Primarily dissolved carbonate minerals which occur naturally in soil and certain rock materials. When carbonate minerals dissolve, they
increase the amount of calcium and magnesium ions in water.
What is pH
The pH test measures the concentration of hydrogen ions in a solution. The concentration of hydrogen
determines if a solution is acidic or basic. The lower the pH, the more corrosive water will be.
Why Test for pH
The pH of groundwater in Wisconsin in typically between 6.5 and 8.5. Lower or higher values can occasionally
occur in parts of the state because of certain geologic characteristics. While there are not health concerns associated with
pH levels typical of Wisconsin groundwater, corrosive water (pH less than 7) is more likely to contain elevated levels of
copper and/or lead if those materials occur in the plumbing system.
Low pH values are most often caused by a lack of carbonate minerals. Low total hardness and alkalinity are often correlated with
low or acidic pH values.
What is Conductivity
Conductivity measures the amount of dissolved substances (or ions) in water; but does not
give an indication of which minerals are present. Changes in conductivity over time may indicate changes
in overall water quality.
Why test for Conductivity
There is no health standard associated conductivity. A normal conductivity value measured in umhos/cm is roughly
twice the total hardness (measured as CaCO3) in unsoftened water samples. If conductivity is significantly greater than twice
the hardness, it may indicate the presence of other human-influenced or naturally occurring ions such as chloride, nitrate,
or sulfate. Because conductivity is relatively easy and cost effective to measrue, understanding variations in conductivity
may help in designing cost effective monitoring strategies for homeowners
to monitor their well water continuously through sensors rather than annual test.
