Pesticide NPDES permit steps to compliance | Step 1: Applicability and thresholds

To help you quickly determine whether this permit affects you, what your requirements are, and what to do next, the MPCA has developed an PDF icon Applicability flow chart (wq-wwprm9-04). Threshold information summarized in the flow chart is discussed in detail below.

Note for R & D programs: If you apply pollutants in, over, or near waters of the state for the sole purpose of “pesticide research and development” as defined in Section 6 of the permit, you must minimize discharges to waters of the state (see Step 3) to the extent that you do not compromise the research design. However, you are not required to submit a NOI or meet the additional requirements of the permit, regardless of the size of the research area.

Which pesticide activities are affected?

The NPDES/SDS Pesticide General Permit covers anyone in Minnesota discharging a pesticide in, over, or near a water of the state for one of the following reasons:

  • Mosquito and Other Flying Insect Pest Control — For public health/nuisance and other flying insect pests that spend a portion of their life cycle in or above water. Includes mosquitoes and black flies.
  • Forest Canopy Insect Pest Control — Application of a pesticide over a forest canopy, where to control a pest effectively, a portion of the pesticide unavoidably will be applied over and deposited to water. Includes gypsy moths and grasshoppers.
  • Aquatic Nuisance Animal Pest Control — Invasive or other nuisance animals in waters of the state. Includes fish, lamprey, and mollusks such as zebra mussels and faucet snails.
  • Vegetative Pests and Algae Control — Aquatic vegetative pests and algae, including terrestrial vegetative pests growing in waters of the state.

If you are using pesticides for one of the reasons listed above and exceed one of the thresholds listed below, you are required to submit a Notice of Intent (NOI) and pay an application fee (see Step 2), and follow permit requirements. 

If you are using pesticides for one of the reasons listed above but do not exceed the thresholds, you must comply with basic permit requirements (see Step 3) but are not required to submit a Notice of Intent or an application fee.

What are the thresholds for submitting the Notice of Intent?

Thresholds are specific to each type of pest being controlled.

Mosquito control

  • All Federal and State governmental entities with the responsibility to control mosquitoes for public health, nuisance control, and animal welfare.
  • Local governmental entities with the responsibility to control mosquitoes for public health, nuisance control, and animal welfare and treat with adulticides and a pest management area of 6,400 acres (10 square miles) or more. A pest management area is the entire area of land, including any water, for which you are conducting pest management activities; it is not based on how much pesticide is actually applied and where.

For example, if you are a public works department responsible for pest control in your city, the pest management area is all the land and water within the city limits, not just the areas where you have applied pesticides.

  • This threshold is not cumulative and it is not a calendar-year total of acres treated.

Other flying insect control

  • Local governmental entities with the responsibility to control flying insects (other than mosquitoes) for public health, nuisance control, and animal welfare and apply 20 gallons or more of pesticides per calendar year.
  • This threshold is cumulative and based on a calendar-year total of gallons applied.

Forest canopy insect pest control

  • All Decision-makers with a treatment area of 6,400 acres (10 square miles) or more. All the areas where the pesticide is intended to have pesticidal effect must be included in the calculation of the treatment area.
  • This threshold is cumulative and is based on a calendar-year total. For example, if you treat the same 100 acre parcel five times in a year, your treatment area is 500 acres. This threshold includes both land and water. If your treatment area does not include any waters of the state, you do not need this permit.

Aquatic nuisance animal pest control

For lakes:

  • Any Decision-maker with a treatment area of 20 acres or more. A treatment area is the entire area where the pesticide is applied and intended to control pests. If wind or waves expand the area affected by the pesticide, you must include that area in the treatment area total.
  • The treatment area is cumulative and based on a calendar year total of where pesticides are applied. For example, if you apply pesticides to two 10-acre lakes three times in a calendar year, your treatment area is 60 acres.

For flowing waters (for example, rivers, streams, and ditches)

  • Anyone with a treatment area of 20 linear miles or more. Linear treatment areas are the linear distance over which pesticides have a pesticidal benefit, including any downstream benefits.
  • When calculating the treatment area, count each pesticide application activity as a separate activity and include pesticidal benefits downstream. For example, if you apply pesticides to 15 linear miles twice in a calendar year, your treatment area is 30 linear miles. In the same example, if you expect pesticidal benefits 10 miles downstream, the treatment area is 50 linear miles.

Vegetative pest and algae control

For lakes 20 acres or more in size:

  • A Decision-maker treating for algae, including partial or whole lake treatment.
  • Anyone treating 15% or more of the littoral zone in a calendar year. The littoral zone is where lake depth is 15 feet or less. Base your calculation on the surface area of the littoral zone (not the volume).

For all other waters of the state, such as streams, rivers, ditches, and wetlands (not including lakes, which are addressed in the above threshold):

  • Any Decision-maker with a treatment area of 1,200 acres or more. A treatment area is the entire area where the pesticide is applied and intended to control pests. 
  • If you are treating an area that is intermittently wet, count it toward the threshold total only when visible or standing water is present.
  • This threshold is cumulative and based on a calendar year total. For example, treating the same 100-acre wetland three times a year would result in a treatment total of 300 acres if water was visible at each application event.

Go to Step 2: Submit A Notice of Intent