Water quality: Aquatic pesticides permit | Colorado Department of Public Health and Environment

You only need a permit to apply pesticides in or next to a drainage way, ditch, canal, stream, wetland, creek, or other surface water.

What you need to know to get started

Pesticide general permit

Reporting templates and change of contact form

Maps

Map of outstanding waters (ArcGIS online map).
2018 inventory of outstanding waters (Zip file with ArcGIS shape files).
Map of Colorado threatened and endangered fish species.
Regulation 93 list of impaired waters in Colorado/TMDL.

Sampling

The division conducted sampling to establish a baseline pesticide data set for each major Colorado watershed.

Guide to interpreting results from aquatic analysis for pesticides.
Summary of all tests by location and test dates.
- Includes specific record numbers for designated reports.
Analysis reports for summary.
- This is the electronic Colorado Environmental Records Center.
- This link goes directly to the analysis and calculations file for pesticide sampling results.
- Tests are referred to by record number only.
- To determine the specific record numbers for location and test date, see list on page one of the Summary of all tests.

Information

General information about Colorado approach
- 2012 Request for Information Report to Colorado General Assembly:
  - Report.
  - Supplement.

Compliance assistance:
- Ditches:
  - No permit is required for any flow or return flow of irrigation water into state waters unless required by federal regulations (Colorado Water Quality Control Act).
  - The state permit for these discharges is consistent with federal permit requirements.
  - The EPA Scope Essay has more information about this topic.
  - To determine whether an annual report must be submitted:
    - Calculate the area of the ditch application, even if it is dry at the time of application.
    - Ditch miles treated should be counted once, even if treated more than once in a calendar year. For example, the water in a ditch on a 10-mile stretch has a 10-mile application to your annual treatment area, even if applications are applied to one side of the ditch first and the other side at a later date.
    - See definitions in Permit COG860000 Part I.I: Annual Treatment Area Threshold.
- Flood irrigation
  - Waters in a field following flood irrigation are "waters withdrawn for use" and are not"waters of the state." Permit coverage is not needed.
  - This water, commingled with irrigation water, is irrigation return flow and/or surface runoff from an agricultural field. Permit coverage is not needed.
- Additional information from Virginia Cooperative Extension:

Pesticide waste disposal information from the Colorado Department of Agriculture

EPA materials

John Nieland

john.nieland@state.co.us | 303-692-3553