High Nitrate Levels in Your Drinking Water

What can you do to reduce nitrate levels in your water?

In Portage County, groundwater supplies 100% of drinking water for both private and public water systems.  

Municipal or Public Water Supply

If you receive municipal water, then your municipality is required by law to regularly test and keep nitrate levels below the MCL for the public water supply.  Municipality's choices to reduce nitrate levels usually include the first three actions discussed in the "Reactive Actions" section below.  

To view your municipality's water test results, visit the DNR's Drinking Water Systems: Public Water Supply web page.  Fill in the first form blank with the name of the community, and then click "find".  In the table that results, click on the far right link, "CCR," which stands for consumer confidence report.  On the CCR report, scroll down to the "Inorganic Contaminants" table and locate "nitrate".

In Portage County,  Plover and Whiting each installed nitrate removal systems on their public water supply totaling $3 million.  Households within those municipalities pay the additional costs for annual operation.

Private Water Supply

Although nitrate is necessary for human and environmental health, high concentrations in drinking water can be harmful.  If your private well water tests reveal that nitrate is higher than 10ppm, the Drinking Water Maximum Contaminant Level (MCL), then you may want to take action to reduce the nitrate in your water.  These actions could either be reactive actions or preventative actions.  Some preventative actions could take several years for the results to show up as improved well water quality.  For example, changing your lawn fertilization practices is important, but probably will not result in immediate well water quality changes.

Before you take action, you should try and figure out what is causing the high nitrate levels in your groundwater.  The following steps will help guide you in determining this.

1. Learn the direction of groundwater flow for your neighborhood or area.

2. Learn what kinds of land use and land practices occur in your neighborhood or area.  Concentrate on the area upgradient from your well, those areas from which groundwater flows toward your well.  (Municipalities should look at the recharge area for the municipal wells.)  

3. Gather information on the depth and construction details of your well.  This information can be found on the DNR's website under "Drinking Water System Well Construction Data" or by requesting a well constructor's report through the mail from the Wisconsin Geological and Natural History Survey (WGNHS).

4.  Draw a schematic map of your property layout.  Where are your house, septic system, and well located and what are the distances between them?  Your septic system should be located downgradient from your well.  Your well should be a minimum of 25 feet from the septic tank and minimum 50 feet from the absorption field or mound.

5.  Analyze or question your findings.  How close are your neighbors?  Could your or your neighbors' septic system be increasing nitrate levels in your water?  Is your well old or improperly constructed?  Do you or your neighbors fertilize your lawn? Is there a dairy operation or agricultural crops upgradient from you?  

6.  Based on your answers to the above questions, see if you can change something.  There are many actions you could take to help reduce the amount of nitrate entering the groundwater.  These actions could either be reactive actions or preventative actions.  However, sometimes the source of the problem is not under your control.  Then, working together to help educate and motivate others can help.  Educating and motivating citizens about groundwater issues is one of the major tasks of the PCGCAC, the PIE subcommittee, and Portage County Groundwater Guardians.

Reactive Actions 

First of all, do not boil the water.  Nitrate is not a bacteria that you can kill.  Boiling water only increases the concentration of nitrate in your water.

A few immediate fixes include:

  • install a nitrate removal system on your private well water supply
  • drill  your well deeper
  • drill a new well
  • purchase bottled water for drinking and cooking purposes

(To determine whether drilling a deeper well or new well might work, you need to know information about your existing well, and the geology  and aquifer properties for your area.)

You also have the choice to do nothing.  Thus far, high nitrate levels have been linked to a possible health risk called Blue Baby Syndrome.  If your household does not have a baby under 6 months of age, a nursing mother, or a pregnant women, then you may decide to do nothing.  However, before making that decision you may want to consider the other possible health impacts associated with high nitrate levels in drinking water and test your well water for possible pesticide contamination.

Lastly, you may also want to check out the preventative actions that could help reduce nitrate levels in the groundwater supply over the long run.

Preventative Actions

(Italicized words defined in the glossary.)

Nitrate:  sources  |  explanation  |  impacts  |  PC levels  |  testing  |  actions

goals and strategies  |  nitrate  |  pesticides  |  quantity
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