Water Quality Division: Permits: Drywell Program
 

General Information

A person who owns an existing or proposed drywell must register the drywell with ADEQ and submit a registration fee of $100 per drywell.

Drywells used in conjunction with golf course maintenance do not need to be registered. However, any vadose zone injection wells (including drywells) that receive stormwater mixed with reclaimed wastewater or groundwater, or both, from manmade bodies of water associated with golf courses, parks, and residential areas must be registered. In this situation, a general permit is issued by statute in lieu of an individual permit, provided that six criteria, including registration, are met (Arizona Revised Statute (A.R.S.) § 49-245.02).

Standard Operating Procedure for the Front Desk

Change of Information

To change existing drywell registration information (such as new ownership, new nature of business, or decommissioning) send written request to:

Arizona Department of Environmental Quality
Drywell Registrations
1110 West Washington Street
Phoenix, Arizona 85007

Please include the drywell registration number(s), the name of the facility, and the requested changes in your letter.

Aquifer Protection Program (APP) and Drywells

APP program requirements apply to certain drywells and injection wells for operation and closure. An APP is required for drywells draining areas where hazardous substances are used, stored, loaded, or treated. If there is question about the status of a drywell, a Determination of Applicability Form is available and may be requested to aid in evaluating regulatory requirements.

Also, general APPs are issued to certain drywells by statute, as provided in A.R.S. § 49-245.02. In addition, certain discharges to drywells in combination with stormwater are exempt from the APP requirements. Eight types of discharges other than stormwater are listed in statute (A.R.S. §§ 49-245 and 49-250(23)).

Regulating Drywells

Drywells can only receive stormwater runoff or discharges that are exempted by A.R.S. § 49-250(23). If other fluids have been directed to the drywell, it is subject to the aquifer protection program (APP) and/or closure requirements and may be considered an underground injection well that requires both ADEQ and USEPA permitting. Spills to the drywell may also trigger permitting, clean closure, or enforcement actions.

Regulations governing drywell operation, etc. are found in:

  • A.R.S. §§ 49-331 through 49-336 (laws regulating drywells);
  • A.R.S. § 49-201(5) (clean closure definition);
  • A.R.S. § 49-241 (permit required to discharge); and
  • A.R.S. § 49-245.02 (general permit for certain discharges associated with man-made bodies of water).

An APP permit is required for any drywell located in an area where hazardous substances, including motor fuels, are used, stored, treated or loaded.

To obtain APP Application Forms - (602) 771-4686

The permitting requirement may not apply if the Site Plan clearly demonstrates that the site is graded or engineered such that drywell(s) can not receive runoff or spills from chemical handling areas.

Drywells in Drainage Areas Where There Are Hazardous Substances

The APP requirements apply to drywells that drain areas where hazardous substances are used, stored, loaded, or treated. An APP is required to ensure that best management practices are followed, and hazardous substances are kept from entering the drywells by using the proper engineering design, physical barriers, and procedural controls.

An APP application requires information about the design of the drywell and development of a Best Management Plan to protect the drywell. The application process also requires sampling of sediment from the settling chamber of the drywell. Generally, initial testing includes TPH, total metals, and organic compounds; however, constituents analyzed should be representative of the chemicals or wastes that are or have been used at the site.

Drywells in Other Areas

If a drywell does not drain areas where hazardous substances are used, stored, loaded, or treated, APP program requirements typically do not apply. However, unless specifically exempt by statute, if a facility adds any pollutant to a drywell, it may be classified as an injection well and be subject to permitting. Any drywell that is used for industrial wastewater disposal, either solely or in conjunction with stormwater discharge, is an injection well. APP program requirements apply to operation or closure of injection wells. Contact the ADEQ Industrial and Drywell Unit if hazardous substances have been detected in your drywell, if unauthorized disposal of waste into the drywell has occurred, or if spills of hazardous substances have entered your drywell.

Closing a Drywell

If a facility proposes to close a drywell that has drained areas where hazardous substances are used, stored, loaded, or otherwise managed, a clean closure application must be submitted to ADEQ for approval. If the facility can demonstrate clean closure of the drywell per A.R.S. § 49-252, an APP will not be required.

For drywells that have not drained such areas but that have received unauthorized spills, ADEQ may request a clean closure application that addresses necessary investigation and remediation.

A drywell that has never drained areas where hazardous materials have been managed and has received only stormwater discharges can be closed at any time.