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Open Feedlots

Iowa’s open feedlots are places where animals are kept in unroofed or partially roofed areas. To be considered an open feedlot, animals are fed and maintained in pens for at least 45 days in a one-year period. Open lots controlled by the same owner that are less than 1,250 feet apart may also be considered one operation. Unlike animals on pasture, manure from the open lot animals is concentrated and the ground is bare of vegetation.

Most open feedlots need some type of solids settling and need to apply manure in a way that will not pollute Iowa streams. Larger lots that have an animal unit capacity of more than 1,000 animal units may also need a National Pollutant Discharge Elimination System (NPDES) permit. Some intermediate size lots may need an NPDES permit if a stream runs through the lot or there is a man-made conveyance for discharging to a stream.

Livestock producers who have animals in both confinement (totally roofed) and open feedlot (partially roofed or unroofed) facilities face a somewhat more complex situation than producers who have only one type of housing. They may need a National Pollutant Discharge Elimination System (NPDES) permit required by federal regulations if a discharge would be expected from the facility. A non-discharging open feedlot that is part of a combined operation will need to follow state regulations for open feedlots. The confinement portion of the operation will need to follow state regulations when operating or building a confinement facility. These combined facility situations can be confusing and complex, so producers are encouraged to contact their local DNR field office to ensure the correct requirements are being followed.

Open feedlot producers are required to manage manure, process wastewater, settleable solids and effluent from the feedlot according to the following:

  • All open lots, regardless of size, that expand or construct new lots in Iowa must meet minimum separation distances to water wells.  These requirements are listed on the Open Lots construction page.
  • Remove all settleable solids from the effluent prior to discharge into a water of the state and ensure that the discharge does not cause a water quality violation. Prevent any direct discharges into publicly owned lakes, known sinkholes or agricultural drainage wells.
  • Land apply all effluent in a way that will not cause pollution of surface or groundwater, including meeting separation distances from environmentally sensitive areas. Additional requirements apply for concentrated animal feeding operations (large and medium CAFOs), including the possible need for a NPDES permit.
  • A nutrient management plan (NMP) is required for any open feedlot with an NPDES permit or capacity of 1,000 animal units (e.g., 1,000 head of cattle or 700 mature dairy cows) or more at any one time. Form 542-0020 can be used to help determine animal units.
  • Stockpiling of settleable solids or manure solids scraped from the feedlot must comply with state law.
    Open Feedlot Manure Stockpiling Regulations
  • Dispose of all dead animals correctly.
  • The U.S. Environmental Protection Agency's website has additional information about federal requirements for concentrated animal feeding operations or CAFOs.


Manure Land Application
Iowa law requires that all manure from an animal feeding operation be properly disposed so that it does not cause surface or groundwater pollution. Animal feeding operations include open feedlots and confinement feeding operations. All sizes of animal feeding operations must meet this requirement. These rules also apply to manure that is produced outside of Iowa, but land applied in Iowa. Open lot dry manure and liquid effluent may be land applied in the winter months on snow covered or frozen ground, but the application must still not result in a water quality violation. Extra precautions such as plugging drainage tile intakes or increasing buffer distances to water, should be taken to ensure any runoff that occurs during snowmelt events or spring thaw conditions does not cause a water quality violation. The Manure Application Webpage contains the requirements for land application of manure.

Separation Distances
There are separation distances that must be maintained between areas of manure land application and protected buildings or other locations such as sinkholes, wells and ag drainage wells. Producers and manure applicators should check the manure application page and the factsheet Separation Distances for Land Application of Manure to determine which separation distances apply to their operation.


Who Needs an NMP?
Open feedlots with 1,000 or more animal units (1,000 beef cattle or 700 mature dairy cattle or 2,500 finishing hogs) must have a nutrient management plan (NMP). Other livestock and poultry producers who must have a NPDES permit must also develop, implement and submit an NMP to the DNR. Producers may not land apply manure, process wastewater or effluent, without an NMP approved by the DNR. Producers who are planning to construct a new facility, or expand or modify an existing facility with 1,000 animal units or more should submit their NMP with the construction permit application.

NMPs - Information for the public
A nutrient management plan (NMP) is a tool that producers use to manage their feedlot's manure and process wastewater, matching up the nutrient value of the manure with the fertilization needs of crops. Properly developed and used, a nutrient management plan prevents over-application of manure. It also provides producers with a valuable fertilizer, saving money and improving organic content of the soil. Producers who have 1,000 beef cattle, 700 mature dairy cattle or 2,500 finishing hogs kept in an unroofed pen are required to have NMPs in Iowa. The public may review the NMP at the appropriate DNR field office at any time and make comments on the NMP to the Department of Natural Resources (DNR).

NMPs - Information for the Producer
For an NMP form, use DNR form 542-2021 (DNR form 542-2021 or DNR form 542-2021), Nutrient Management Plan. This form is available as a Word, Excel, or PDF format. Producers must submit a copy of the NMP to the appropriate DNR field office. Allow 60 days for the DNR to review and approve or disapprove the plan. This includes time for the public to comment on the plan or request a public hearing. When developing a new plan, include time to:

  • calculate how much cropland is needed to land apply manure,
  • obtain soil samples less than four years old,
  • calculate the P index and soil loss (RUSLE2) for each field where manure or effluent will be land applied, and
  • obtain written agreements if spreading on land not owned or rented by the producer.
  • Keep accurate records of manure application. Application record keeping form (DNR Form 542-8002) may be used for these records.


Publishing Public Notice:
Producers must publish a public notice (DNR form 542-1553, Public Notice for NMP at Open Feedlot) on the NMP, including where the NMP can be reviewed, in a newspaper of general circulation in the county or counties

  • where the feedlot is or will be located, and
  • where manure, process waste water or open feedlot effluent will be land-applied.

Producers must submit a clipping(s) or copy of the actual notice(s), including the publication date and newspaper name to the appropriate DNR field office. This information should be submitted to the DNR as soon as possible if not included with the NMP submittal, but no later than five days after the publication date. The DNR will consider public comments when reviewing the NMP. The DNR will also consider requests for a public hearing and notify the producer if a hearing is scheduled.

Open feedlots that wish to expand and will then need to obtain an NPDES discharge permit or are otherwise required to obtain an NPDES discharge permit must furnish the following as part of the NPDES application process.

Alternative Technology (AT) Sites

In lieu of a traditional runoff control basin at an open feedlot, an operation may choose to use an alternative technology, commonly called AT. The DNR has rules and design standards for these AT systems. Instead of a basin, the feedlot runoff is stored and treated in Vegetative Treatment Areas (VTA) and/or Vegetated Infiltration Basins (VIB). These vegetated areas are planted in grasses that help remove nutrients from the runoff prior to discharging to a field. As of 2020, there are 11 NPDES permitted AT sites in the state. If you would like more information on AT technology contact an AFO engineer in Field Office 2 or 3.

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