Water Quality Division: Compliance: Compliance Assurance: Pesticide Groundwater Quality Protection

Notice to Registrants of Pesticide Products

The Arizona Pesticide Groundwater Quality Protection Program was established to prevent or eliminate the pollution of groundwater aquifers of the state from routine use of agricultural pesticides. The program is responsible for evaluating groundwater data submitted in support of new pesticide product registration, and identifying which active ingredients and products have the potential of polluting Arizona groundwater. The program generates the Groundwater Protection List (GWPL), enforces any data gap violations and conducts regular groundwater monitoring. An annual report on pesticide use is presented to the state legislature.

Pursuant to the Environmental Quality Act of 1986, ADEQ requires applicants intending to register new agricultural-use pesticides with the Arizona Department of Agriculture to submit groundwater protection data for review and approval. After completing a substantive technical review, ADEQ determines if the product's active ingredient poses a threat to groundwater quality.

The term "agricultural use" is defined to include all applications of substances to:

  • Repel
  • Kill
  • Control any "pest"


  • Weeds
  • Insects
  • Rodents
  • Fungi
  • Microorganisms

In the following areas:

  • Commercial greenhouses
  • Cropland
  • Food and fiber production
  • Forests
  • Irrigation ditches
  • Rangeland
  • Ground applied seed protection
  • Soil fumigation
  • Tree farms
  • Sod farms
  • aquatics

To help expedite product registration, ADEQ encourages registrants who are not familiar with the Arizona registration process, to provide preliminary information by completing the New Agricultural Use Pesticide Evaluation Form prior to data submittal.

The submittal of groundwater data, unless the ADEQ Director grants a waiver, applies to all new U.S. EPA registered, agricultural use pesticides, including products with a new active ingredient or those containing currently approved active ingredient, also known as "me too" products or "generics". Supplemental registrants (distributors) and formulators are only exempt from the data requirements if they rely on data from another company or primary registrant, and provide documentation of a business arrangement or a letter of authorization (LOA) to use data available at ADEQ.

All pesticide product data submitted to ADEQ, including the product chemistry and environmental fate studies of the corresponding active ingredient(s) must be consistent with U. S. EPA guidelines for these studies and comply with Arizona environmental (soil) requirements. ADEQ will evaluate the data submitted by applicants, determine their adequacy, validity, and completeness, and inform the intended registrant of the outcome within specific time frames for administrative completeness and substantive technical review. All data submitted must be complete, presented in English, and summarized on the Data Summary Form. The following are the guidelines for data submittal for the various categories of prospective registrants.


New Product Categories

To facilitate the submittal of appropriate data and/or documents for ADEQ evaluation, pesticide products are classified into three main categories:

  • New Pesticide Product with a New Active Ingredient
  • New Pesticide Product with a Previously Approved Active Ingredient
  • New Pesticide Product granted a Waiver.

New Pesticide Product with a New Active Ingredient

There are two approaches available to registrants in submitting environmental fate data for products with new active ingredients as defined in § A.R.S 49-302, 49-303(3) and A.A.C. R18-6-102.

  • Standard Evaluation Process - This approach evaluates the potential of a pesticide's active ingredient(s) to pollute groundwater by requiring numeric data on a number of factors affecting the mobility and persistence of a pesticide product. These values are compared to standards or criteria established by ADEQ, called "Specific Numeric Values" (SNVs). The numeric values obtained from submitted studies must have been performed using testing methods described in U.S. EPA's Pesticide Assessment Guidelines. Pesticides that exceed these criteria outlined in Table 1 in both mobility and persistence criteria will be placed on the GWPL.

  • Alternate Evaluation Process - In accordance with A.R.S § 49-302(E) and A.A.C. R18-6-102(2), a prospective registrant may submit alternate information to satisfy one or more of the data requirements. The alternate information will accurately describe the relevant data required for each new pesticide active ingredient under similar environmental and use conditions as Arizona. Supporting documents acceptable to ADEQ include data summaries or product evaluation reports from other states in the southwest USA (such as California), or the U.S. EPA product data reviews. Additional information should include a detailed written assessment of the environmental fate of the active ingredient with respect to environmental conditions similar to Arizona's, including consideration of factors such as proposed patterns of use, applicable cultural practices, and pertinent geologic and meteorologic conditions. A list of the required documents and studies are listed in Table 2.

ADEQ rules allow an applicant to submit any other relevant scientific data and summaries where the additional data may enhance the ability of ADEQ to determine whether the pesticide's active ingredient has a potential to pollute groundwater. However, submittal of these information, evaluations and conclusions from other states or agencies, especially those not in the southwest, may not add to the completeness determination.

All supporting documents or studies should be submitted according to the following procedure:

  • Index each volume submitted.
  • Tab the margin of each study with the study type.
  • Identify each volume as being submitted in response to the data call-in with a conspicuous, brightly-colored note on the outside cover.

New Pesticide Product Containing a Previously Approved Active Ingredient

A prospective applicant for registration of a new product containing an active ingredient previously approved by ADEQ ("me too" products) should indicate if the company is a manufacturer, formulator, supplementary registrant or distributor, and provide information on the source of its technical product. Groundwater data requirements will depend on which of the following sub-categories the prospective registrant belongs.

  • Manufacturer - Technical product is manufactured directly by the registrant.
  • Formulator - Technical product is purchased from existing registrant and reformulated.
  • Supplemental Registrant or Distributor - Existing product is re-labeled and distributed under a name and address other than that of the primary registrant whose product may or may not have been registered in Arizona.

    1. Manufacturer - If the prospective registrant is a manufacturer of a new product containing an active ingredient previously evaluated and approved by ADEQ, the applicant will comply with the data submittal requirements as follows:

      1. If the applicant wishes to refer to existing groundwater data at ADEQ submitted by another company with a similar or substantially similar product (same active ingredient), the applicant must demonstrate substantial similarity of products and provide, along with the U.S. EPA approved product label, relevant documentation of a business arrangement or a letter of authorization from the company that owns the groundwater data.

      2. In the alternative, if the applicant's product is already registered in California, the applicant may provide the following documents in support of the application.
        1. Cover letter
        2. U.S. EPA stamped/accepted label
        3. California DPR letter of registration and Product Evaluation Report
        4. U.S. EPA letter indicating substantial similarity of products or Technical Product chemistry or U.S. EPA Statement of Formula

    2. Formulator - If the applicant is a formulator and wants to rely on the information generated by another company to meet the data requirements, such applicant must provide, along with the U.S. EPA approved label, a letter of authorization or evidence of a business arrangement with the supplier(s) or owner(s) of the data. In the event the supplier or owner will not support the applicant's registration, the prospective registrant will ultimately be responsible for providing the information to support the product registration.

    3. Supplemental Registrant - If the applicant is a supplemental registrant of a product whose active ingredient has not been previously approved by ADEQ, the applicant must comply with the data requirements of a new product with a new active ingredient as in Category 1. If the primary product with same active ingredient(s) was previously registered in Arizona, the applicant must provide along with the U.S. EPA approved label, a letter of authorization or evidence of a business arrangement with the primary registrant of the product's active ingredient (s). In the event that the primary registrant will not support the registration, the supplementary registrant will ultimately be responsible for providing the information to support the product registration.

New Pesticide Product with a Waiver

In accordance with A.R.S. § 49-302(D) and A.A.C. R18-6-102(A) (3), ADEQ may waive groundwater data submittal requirements if the product's active ingredient by its nature or mode of occurrence will not pose a risk to groundwater quality. The following products will be considered for a Waiver request.

  • Biopesticides as defined by the U.S. EPA to include naturally occurring substances that control pests (biochemical pesticides), microorganisms that control pests (microbial pesticides), and pesticidal substances produced by plants containing added genetic material (plant-incorporated protectants) or PIPs.

  • Products granted U.S. EPA waiver of Tier II environmental fate data requirements.

  • Other products that are made of naturally occurring geological materials ("geopesticides") or mineral matter that are common or ubiquitous in nature (e.g. kaolin, sulfur, copper sulfate or iron phosphate), and pose no perceptible risk to groundwater quality.

Applicants for a Waiver will submit the following documents in support of the product registration.

  • Cover letter
  • Product information
  • U.S. EPA approved label
  • U.S. EPA waiver approval or California DPR product review report (if applicable)

Application Time Frames

The data review/approval for new pesticide active ingredients under A.R.S. § 49-302(F) and A.A.C. R18-6-102(B) of the Pesticide Groundwater Quality Protection Program is subject to the requirements of the licensing time frame statute under A.R.S. § 41-1072 through 41-1079 and the licensing time frame rule A.A.C. R18-1-501 through R18-1-525. The Administrative Completeness review time frame is 21 days and the Substantive Review time frame is 42 days. All submissions in response to this Notice must include the required documents and must be addressed to:

David Haag, Pesticide Program Coordinator
Arizona Department of Environmental Quality
Water Quality Division
1110 West Washington Street, 5415B-3
Phoenix, Arizona 85007
(602) 771-4669

Arizona Soil Requirements for Groundwater Protection Data

All data submitted to ADEQ involving soil testing are required to meet the Arizona agricultural soil requirements (A.R.S. § 49-302(C)) with respect to soil pH and soil organic carbon content. Soils from the United States, particularly the southwest are preferred.

  1. The pH of soils used for soil adsorption coefficient, soil photolysis, aerobic and anaerobic soil metabolism and field dissipation studies must be between 6.5 and 8.5 which accurately reflect the pH range found in Arizona agricultural soils.

  2. The organic carbon content of soils used for soil adsorption coefficient, soil photolysis, aerobic and anaerobic soil metabolism and field dissipation studies must be less than or equal to 2.6 percent. This range most accurately reflects the organic carbon content of Arizona agricultural soils.

  3. Three different Arizona like soils are required for the soil adsorption coefficient study and two different Arizona like soils are required for the field dissipation study.

  4. The same soil must be used for both aerobic and anaerobic soil metabolism studies.

  5. Field dissipation studies must be conducted in the field, and laboratory studies submitted for this requirement will not be accepted. Likewise, field studies submitted in support of laboratory studies will not be accepted.

  6. Aquatic field dissipation studies may not be required for those pesticides intended for aquatic uses if a terrestrial field dissipation study has been submitted and accepted.

  7. Tank mix field dissipation studies are not required for those compounds included in a tank mix if separate terrestrial field dissipation studies have been submitted and accepted for each component active ingredient of the tank mix.

  8. Forestry field dissipation studies need not include soils which meet pH and percent organic carbon criteria of Arizona agricultural soils.

  9. For more information regarding the criteria of the groundwater protection data, please refer to Subdivision D and N of the U.S. EPA's Pesticide Assessment Guidelines.

Groundwater Protection List

According to A.R.S. § 49-305, the Arizona Department of Environmental Quality is required to establish a Groundwater Protection List (GWPL or List) containing pesticide products and their active ingredients that have the potential to pollute groundwater. ADEQ conducts a monitoring program of the GWPL active ingredients in groundwater and soils to accurately determine their mobility and whether they have migrated to groundwater.

Each year, the GWPL is revised and presented for public comment. The annual revised list consists of additions and deletions from the previous list, based on new registrations and deletions of active ingredients. Active ingredients may be removed from the list for several reasons outlined in A.A.C. R18-6-301. The final GWPL after public comment is published each year and becomes effective on December 1 of the publication year. The current list of active ingredients on the GWPL is shown in Table 3.

The GWPL enables ADEQ to focus its statewide groundwater and soil monitoring activities on the active ingredients requiring monitoring and testing. If any of these pesticide active ingredients is detected in groundwater or soil as a result of agricultural activities, ADEQ may, depending on the level at which they were detected, require registrants to modify their application use patterns or may recommend to the Arizona Department of Agriculture to cancel the registration to prevent further contamination.

Both statute (A.R.S. § 49-305(A)) and rule (A.A.C. R18-6-303) require ADEQ to regulate the use of those pesticides on the GWPL intended for application to or injection into the soil by ground based application equipment or chemigation, or if the application site will be flood or furrow irrigated within 72 hours of application of the pesticide based on label recommendations.

The rule requires that any person who soil applies an agricultural use pesticide on the GWPL must implement Best Management Practices to reduce or prevent the pollution of groundwater. This requirement applies equally to a person who hires another individual to soil apply an agricultural use pesticides on the GWPL such as an aerial applicator, pest control advisor, or farm workers.

Related Statutes and Rules