Wisconsin – Composting Rules

Wisconsin, like its regional counterpart in Ohio, revised its composting regulations in the early 2010s; the new rules came into effect June 1, 2012. To ensure the quality of finished compost and minimize potential nuisances from materials mismanagement, the revisions require that composters use best management practices to curtail potential pathogens. Overall, the current regulations are conducive to the growth of the state’s composting industry.

Not all composters are subject to the 2012 rule change, as regulations generally do not apply to home and small-scale (less than 50 cubic yards) composting. The current rules found in Chapter NR 500 – (DNR # WA – 33 – 10) of the Wisconsin Administrative Code provide various composting operations with licensing exemptions based on the type, capacity, and feedstock of the facility, as summarized below.

According to Jennifer Huffman of Wisconsin’s Department of Natural Resources (DNR), volume thresholds are imposed on composting facilities contingent on the amount of material “believed to be manageable at the time the composting rule was drafted.” In general, operations with higher threshold limits are subject to a higher degree of regulation.


Partially-exempt Facilities

NR 502.12 of the Wisconsin Administrative Code stipulates partial/limited exemption for composting facilities of different sizes handling particular types of organic materials. Because “exempt” facilities are still required to meet basic performance and location criteria, the Wisconsin DNR now uses the term “partial exemption” says Brad Wolbert of Wisconsin DNR. “Exempt yard and source-separated compostable material (SSCM) facilities must also follow basic operational and design standards, and exempt SSCM facilities must submit a plan of operation for approval,” he explained further.

The following types of operations are exempt from licensing requirements:

  • Facilities accepting yard debris and clean chipped wood are exempt so long as the amount of material on-site at any one time is equal to or below 20,000 cubic yards.
  • For facilities accepting “source-separated compostable material” the threshold is 5,000 cubic yards on-site at any one time.
    • Threshold calculations do not include storage of finished compost, which is a policy element that clearly benefits sellers of the product.


On-farm Composting

For the most part, farms in Wisconsin are largely exempt from licensing regulations as there is no volume constraint for composting farm crop residue and manure generated on-site. On-farm composters need only meet performance standards in NR 502.04 of the Wisconsin Administrative Code, which require operating in a way that does not cause environmental harm to the farm’s surrounding area.

If a farm is receiving material generated off-site, the threshold limit to remain exempt is 10,000 cubic yards on-site at one time. This calculation is based on the combined volume of farm crop residue, farm animal manure, yard waste, and clean chipped wood on-site at one time. This calculation takes into account collected feedstocks, the composting process, and finished compost for the final sum.


Non-exempt Facilities

All facilities that do not satisfy the partial exemption criteria (and non-farm facilities with greater than 50 cubic yards) must obtain a license to compost. Licenses are free.

Non-exempt facilities are subject to more stringent standards, for example:

  • Submitting construction documentation before beginning operations
  • Designing adequate pad and leachate collection methods (for stormwater management)
  • Performing sampling for common characteristics such as carbon to nitrogen ratio, moisture content, oxygen content, pH, and etc.
  • Potentially providing proof of financial responsibility for closure (for very large sites)


Economic Benefits

The state of Wisconsin recognizes the economic benefits for farmers, businesses, and communities that come from sale of finished compost and accordingly wrote a policy that incentivizes growing markets for compost products. While some states have limitations on the quantity of compost that farmers and facilities can sell, Wisconsin allows licensed facilities to sell all of their compost without restriction, provided that safety and quality standards are met. Since compost is a value-added farm product, this provides additional revenue for both farmers and other composters.

The Wisconsin DNR website reports as of 2021 that there are approximately 200 licensed composting facilities operating in the state, which collectively process about 200,000 tons of yard waste each year. In addition, the DNR asserts that “hundreds of thousands more tons of yard materials are managed through home composting and mulching in place.”


More Information

Original post from July 30, 2012
Updated July 28, 2021