Phosphorus is a key nutrient needed for plant growth which is why it is often applied to gardens, lawns and agricultural fields. However, when it rains phosphorus can run off into local water bodies and fuel algae growth instead. One pound of phosphorus can produce 300-500 pounds of algae. Find out more about phosphorus in lawns, landscapes and lakes (PDF). Dane County and community partners are involved in many initiatives in both rural and urban areas to reduce phosphorus runoff, and several are described below.

Yahara Watershed Phosphorus Reduction Initiatives

To address the issue of phosphorus in the Yahara Watershed, 30 partners have come together to pioneer a new regulatory approach called watershed adaptive management in which all sources of phosphorus in a watershed work together to meet water quality goals related to phosphorus. Find out more about the Yahara Watershed Improvement Network (WINs) project on the Madison Metropolitan Sewerage District website.

Prior work and phosphorus reduction investments in the Yahara watershed set the stage for current collaborative phosphorus reduction successes. This work included the Yahara CLEAN (PDF) initiative beginning in 2008 by Dane County, City of Madison, Wisconsin Department of Natural Resources, and the Department of Agriculture Trade and Consumer Protection. The Clean Lakes Alliance's subsequent CLEAN work (PDF) is focused on community phosphorus reductions, awareness, and fundraising. Other organizations in the Dane County Watershed Network are also contributing to phosphorus reduction goals.

Lawn Fertilizer

In order to improve lake water quality by reducing phosphorus runoff, based on the recommendation of the Dane County Lakes Select a lawn fertilizer with a middle number of 0and Watershed Commission, the Dane County Board adopted Ch. 80 of the Dane County Code of Ordinances, "Establishing Regulations for Lawn Fertilizer Application and Sale (PDF)." Fertilizers normally contain a mix of nutrients, including nitrogen, phosphorus and potassium.  The ordinance went into effect in January 2005 in every town, village and city in Dane County. Signs containing the ordinance requirements and the effects of phosphorus on Dane County waters must be prominently displayed where lawn fertilizers are sold.

The ordinance:

  • Prohibits use of phosphorus-containing lawn fertilizers, unless a soil test shows that phosphorus is necessary, or the fertilizer is to be used on a new lawn in its first growing season.
  • Prohibits retail display of phosphorus-containing lawn fertilizers

Signs for Retailers:

Manure Management

In 2008, a Community Manure Feasibility Study Committee completed its examination of alternatives for livestock manure management in Dane County that would allow the livestock industry to continue to survive, protect water quality, and protect open space.  Find out more on the Dane County Land Conservation Division website. The work of this committee paved the way for development of manure digesters that contribute to phosphorus reduction.

Dane County has also established requirements for manure storage, and for winter application of stored pumpable liquid manure in order to protect the health and welfare of Dane County’s residents and the economic and environmental value of the county’s natural resources. The Land Conservation Division administers these programs, and assists agricultural producers with nutrient management planning and other conservation practices.

Leaf Management

Decaying leaves are a great natural fertilizer for gardens and lawns, but they also release unwanted nutrients into our local waters. When it rains, stormwater flows through leaf piles in streets creating a "leaf tea" that is rich in dissolved phosphorus. The phosphorus present in this "leaf tea" is not removed through traditional stormwater treatment practices and is carried through our storm sewers to local lakes, rivers and streams. Learn how you can manage your leaves in a way that protects local water resources on the Ripple Effects website.

What Dane County Residents Can Do

In urban and rural areas:

In rural areas:


Nitrate (NO3) is a compound made up of nitrogen and oxygen, formed when nitrogen from ammonia or other sources combines with oxygen in water. Levels higher than 2 mg/L indicate a source of contamination, and the Wisconsin Department of Natural Resources (PDF) recommends avoiding long-term consumption of water containing nitrate above the health-based enforcement standard of 10 mg/L. In addition to the effects on human health, a number of studies have shown that elevated nitrate concentrations can harm or kill a variety of species of fishes, amphibians, and aquatic invertebrates.


Potential sources of nitrate pollution include nitrogen fertilizers, manure, on-site and municipal wastewater treatment systems, animal feedlots, sludge and septage application, silage leachate, and decaying plant material.

In Wisconsin, 90% of the groundwater nitrate contamination is estimated to have originated from agriculture, 9% from septic systems, and 1% from other sources (B. Shaw, 1994, PDF).

Nitrates in Dane County Groundwater

In its 2014 Water Quality Report Card (PDF), Madison and Dane County Environmental Health reported that nitrate contamination continues to be a problem in private wells in Dane County households. Over the past decade, several thousand private well water samples have been tested for nitrate, and that available data show that:

  • 18% of the private wells tested exceeded the drinking water standard of 10 mg/L
  • 54% of the wells tested contained between 2 mg/L and 10 mg/L, indicating land use has likely affected groundwater quality
  • 28% of the wells tested below the preventive action limit of 2 mg/L, indicating no likely sources of contamination
  • Nitrate concentrations exceeding 10 mg/L are less prevalent in municipal drinking water samples in Dane County (because the wells are deeper than private wells).

Nitrates in Dane County Surface Water

The concentration of nitrate-nitrogen in most county streams has seen an increase over the last 35 years. This is attributed to the large amounts of nitrogen fertilizer used in the region, one of the most agriculturally productive in the nation. Nitrate nitrogen levels have been recently declining, likely the result of increased agricultural nutrient management planning and practices (Capital Area Regional Planning Commission, 2014, PDF).

What Dane County is Doing

Lake researchers at UW-Madison believe that evidence is strong enough to suggest that both phosphorus and nitrogen inputs to the Yahara lakes should be controlled to improve lake health. Fortunately, many of the conservation practices installed by agricultural producers, supported by Dane County and many partners, reduce inputs of both nutrients (R. Lathrop, 2007, PDF). 

What Dane County Residents Can Do

In urban and rural areas:

In rural areas:


Information from Wisconsin Department of Natural Resources 

Sediment is the loose sand, clay, silt, and other soil that settles to the bottom of a water. The U.S. Environmental Protection Agency lists sediment as the most common pollutant in rivers, streams, lakes, and reservoirs. When sediment enters a waterbody, it smothers valuable aquatic breeding ground, damages fish gills, fills in stream channels (which increases the chance of flooding), contributes to the erosion of stream banks, decreases the recreational value of the waterbody, and can be costly for drinking water treatment plants to filter out. In addition, sediment often carries nutrients with it into streams and lakes.

While natural erosion produces nearly 30 percent of the total sediment in the United States, erosion from human use of land accounts for the remaining 70 percent. In agricultural watersheds, the most significant source of sediment is tilled fields. Farm fields, especially when conventional tilling is used, lack a continuous layer of vegetation to hold the soil in place, so sediment runoff is a major concern. Improperly managed construction sites also contribute significant amounts of sediment to local waterways. Construction activities disturb land and can cause sediment to leave a development site. Another significant source of sediment comes from domestic animal activity. Without proper management, livestock can over–graze, creating pasture erosion and trampling stream banks.

Additional Information:

The Wisconsin Runoff portal provides information spanning multiple agencies in the area of sediment runoff and loading to Wisconsin waters.

Find out more about how Dane County administers erosion control and stormwater management requirements and check out the Water Resource Engineering Division website that describes local erosion control and shoreland erosion control permits.

The Dane County Land Conservation Division and the Natural Resources Conservation Service offer cost-share programs that can help agricultural producers tackle erosion issues.

What Dane County Residents Can Do

  • In urban areas, rain water runs off into storm drains and directly into our lakes rivers and streams.  This high influx of water into rivers and streams can cause increased erosion. Reduce the amount of rainwater running off your property by installing a rain barrel or rain garden.
  • If you are an agricultural producer, contact the Land Conservation Division to learn more about conservation practices and cost-share programs in your area that can help reduce erosion on your land.
  • Plant native plants in your yard or on your land.  The deep roots can help infiltrate water and hold soil in place.

Chlorides (salt)

Wisconsin is known for its brutal and unforgiving winters, so residents take extra steps to make sure we’re safe throughout winter storms. This includes using salt to deice the walking and driving surfaces at our homes and businesses. Once you put salt down, it doesn’t go away. It washes into our storm drains and ends up in our local lakes and streams. The Office of Lakes and Watersheds is working with a number of partners throughout the local area to promote wise winter practices.

What Dane County Residents Can Do

You can keep sidewalks and driveways safe this winter while protecting our waters by following these simple steps:

Shovel. Clear walkways and other areas before the snow turns to ice. The more snow you remove manually, the less salt you will have to use and the more effective it will be.Scatter.  If you apply salt to pavement, aim for a well distributed pattern, leaving space between salt grains.  A coffee mug full of salt is enough for about 10 sidewalk squares. A hand spreader can help create this pattern.Switch. When pavement temperature is below 15 degrees, salt won't work. Switch to a different ice melter (like a blend) that works at lower temperature, or use sand for traction.

To find out more, visit the Wisconsin Salt Wise website or check out this helpful presentation (PDF) put together by the Madison Metropolitan Sewerage District.


What Winter Maintenance Applicators Can Do

Winter maintenance professionals who clear snow and ice from parking lots, sidewalks, and trails can use locally-tailored application rate guidelines for using the least amount of salt to get the job done. They can also voluntarily become certified to demonstrate to their clients that they work for their safety and for the protection of our lakes, streams and drinking water. Visit the Winter Salt Certification webpage to learn more about this program.

Coal Tar

Coal tar sealants contain high levels of polycyclic aromatic hydrocarbons (PAHs), which are toxic to fish and other aquatic life. The Lakes and Watershed Commission's ordinance regulating coal tar sealant use and sale in Dane County (PDF) was adopted by the County Board and went into effect in 2007. The ordinance bans use, sale or retail display of sealcoat products anywhere within Dane County that are labeled as containing coal tar. It also requires retailers to prominently display information about the ordinance (such as this PDF flyer) where customers make their driveway sealant purchases.  There is an ordinance exemption for those who intend to apply sealcoat products on a surface that is not located within Dane County. Sellers must require purchasers seeking the exemption to complete this form (PDF).

More information about this ordinance is available in this fact sheet (PDF).

What Dane County Residents Can Do

Check the label and don’t buy products containing coal tar. Instead, opt for safer products such as asphalt sealcoats or latex modified asphalt sealer.

Thermal Pollution

When human activities change the temperature of the water, we call this thermal pollution.  These temperature changes can negatively affect fish and aquatic life in Wisconsin’s surface waters and alter the water chemistry (which in turn impacts aquatic life).

Impacts of thermal pollution:

  • Reduced reproductive success of fish and aquatic life
  • Habitat degradation
  • Fish kills (in extreme cases)

Common causes of thermal pollution are:

  • Coolant water: water used as a coolant for power plants and industrial manufacturers, then returned to the natural environment.
  • Soil Erosion: Soil that washes into a water body makes it muddy and murky. This can lead to the water body absorbing more light and increasing in temperature.
  • Deforestation: removing trees or plants that previously shaded a waterbody can expose it to sunlight causing the water to absorb more heat. 
  • Runoff from paved surfaces: during the summer, paved surfaces (such as streets, driveways, and sidewalks) can get quite hot. As rainwater runs off of these surfaces it heats up before entering the storm sewer and draining to a nearby water body.

Learn more about thermal pollution on the Wisconsin Department of Natural Resources website. Visit the Water Resources Engineering website to learn about thermally sensitive areas in Dane County and how the Dane County stormwater requirements help to protect thermally sensitive waters including trout streams.

What Dane County Residents Can Do

In urban areas, rain water runs off into storm drains and directly into our lakes rivers and streams.  In the summer, the water heats up as it runs over hot pavement before emptying into our waterways.  Reduce the amount of rainwater running off your property and over hot pavement by installing a rain barrel or rain garden.

Household Hazardous Materials

There are many materials we use every day that, if disposed oHazardous household chemicalsf improperly, can degrade our surface water and groundwater supplies. These include cleaning agents, paint products, batteries, electronics, and a number of other common items. These items should not be thrown away in your household trash and should be collected and disposed of properly.


Dane County Clean Sweep: Clean Sweep is a place to bring hazardous household materials such as oil-based paints and paint-related products, pesticides and poisons, household products containing organic solvents, ignitables and aerosols, and rechargeable batteries. Find out more about the Clean Sweep program, fees, and drop off location hours on the Dane County Clean Sweep website.  The free product exchange area at Clean Sweep is a great place to take or leave useable products like paint, thinners, solvents, and pesticides.

Safe Substitutes for Household Products: The City of Madison has compiled a list of non-toxic  substitutes for commonly-used household products that are hazardous to humans or the environment. You can find the list on the City of Madison website.

Safe Communities MedDrop Program: Proper disposal of leftover and expired prescriptions and over-the-counter medicines. Find out more about the MedDrop Program and drop off locations on the MedDrop website.

Dispose My Meds Program: An online resource to help you find medication disposal programs at an independent community pharmacy in your neighborhood. 

Learn What Not to Flush: What we put down our drains and toilets can negatively impact our environment and put our health at risk. Even items labeled flushable can clog pipes, tangle pumps and result in messy and costly sewer backups. By educating ourselves and each other, we can avoid expensive and dangerous mistakes while improving our sewer system practices and protecting our waters. Find out what you shouldn’t flush and other ways you can help with these helpful tips from the Madison Metropolitan Sewerage District. These helpful tips are also good practices for your on-site wastewater treatment system.