Water Well Construction Related Wastewater and General Permit #6

NOTICE - Stakeholder Input Wanted - General Permit #6 Renewal

The NPDES General Permit for Well Construction and Well Service Discharges (also known as GP6) will expire on February 28, 2020. Iowa DNR proposes to initiate rulemaking to renew the permit for a third 5 year term. The proposed GP6 is nearly identical to the current general permit except for some clarifications.

The permit renewal process includes asking for comments from individual stakeholders, stakeholder groups, and other interested citizens. A stakeholder meeting regarding the renewal is scheduled for 3:00 PM on Thursday, May 24, 2018. The meeting will be held in Conference Rooms 4 East and West on the fourth floor of the Wallace State Office Building, 502 E. 9th Street, Des Moines, IA 50319. Free parking is available in the public parking ramp located directly west across the street from the Wallace Building.

Written comments regarding the rulemaking and the proposed general permit can be submitted until May 31, 2018. Please send your written comments via email to Wendy Hieb at wendy.hieb@dnr.iowa.gov or by US Postal Service to Wendy Hieb, Iowa Department of Natural Resources, 502 E. 9th Street, Des Moines, IA 50319.

Use the following link to view the proposed general permit #6: Proposed GP6.

Questions regarding the meeting or comment period can be addressed to Wendy Hieb at at wendy.hieb@dnr.iowa.gov or 515-725-8405.

About General Permit #6

The 82nd State General Assembly passed a statute which required the Department to write new rules and a provide issuance of a General Permit to authorize well construction and well services related wastewater discharge when that discharge reaches a Water of the United States. Beginning on March 17, 2010, all well construction, well related service and GHEX loop borehole drilling related wastewater that reaches a Water of the United States is regulated by National Pollution Discharge Elimination System permit (NPDES) General Permit #6 (GP6).

What is well construction wastewater?

Well construction wastewater is the wastewater generated by any well drilling related activity in our state. These activities include new well construction, existing well rehabilitation and renovation, pump installation, test pumping, geothermal borehole drilling, water observation well installation, water well test hole and test well drilling, and other types of drilling that access or utilize the groundwater for a specific purpose. The wastewater generated during these activities can be made up of drilling fluids, groundwater or a combination of both, can be very turbid to nearly clear and can contain geologic materials and chemicals used to enhance drilling. If the well drilling related discharge leaves the construction site it becomes wastewater discharge.

Anytime the wastewater generated by well related construction and services discharges off the well construction site and reaches a Water of the United States, the wastewater falls under the requirements of GP6. GP6 requires the wastewater to comply with the treatment standards and discharge requirements stated in GP6. If the well construction or well services related wastewater does not reach Waters of the United States, the discharge is not subject to GP6.

Why is well construction and well service related wastewater regulated?

Many well construction sites are located near ditches, waterways, or subsurface drainage inlets that may allow well construction related wastewater to reach a Water of the United States. Well construction related wastewater normally consists of diluted drilling fluids and/or groundwater, and contains particles of natural materials like sand, silt, colloids (clay), limestone and dolomite, and possibly various chemicals used to enhance the drilling fluid. When allowed to flow untreated, the wastewater may eventually reach a stream, river or a lake. This can result in turbidity that can affect aquatic life and accumulation of sediments that create undesirable changes to the stream or lake bed.

In addition, drilling fluid additives and other products used in drilling and servicing wells may contain substances that are acutely toxic to aquatic life. These products can chemically and physically alter the water body and cause additional problems like killing aquatic life and inhibiting the life processes for all species that depend on the water. Untreated discharges also impact the manner in which the water is used or enjoyed by adjoining property owners and others who have access to the water.

Well construction discharge at the point of stream entry.
Well construction discharge after mixing - downstream several hundred feet.
Well discharge near stream entry point. Well discharge after mixing downstream.

What well services are included in GP6?

  • All types of new water supply well construction including:
    • Private and public water drinking water supply wells, observations wells, test wells and test drilling
    • Non-potable use wells such as irrigation wells, plant process water supplies and dewatering wells
    • Geothermal use water supply wells
    • Groundwater injection return wells (geothermal injection wells)
    • Geothermal loop borehole construction
    • Compressed air/gas injection well construction
  • All types of services performed on existing wells, like renovation or rehabilitation services
  • All types of well pump repair on all types of water wells when the well will be pumped to waste
  • Development, rehabilitation and test pumping on new or existing water supply wells

What types of well discharges are not included in GP6?
  • The actual production pumping and on-going operation of dewatering wells - please contact your local Field Services Office for additional information on discharge standards for these types of activities.
  • The construction of oil and gas test wells and production wells - please contact IDNR staff listed at the bottom of the page for more information on these discharges.

How do I comply with GP6?

Iowa's NPDES General Permit No. 6 requires the development of a well site specific well water pollution prevention plan (WWPPP or Plan) for the each well construction site where the discharge reaches a Water of the United States. When an engineer is used to develop the well plans, an engineer must also develop and create the WWPPP for the permittee. For wells that do not require the services of an engineer, the WWPPP can be developed by the well/landowner (permittee) or by a contractor or agent retained by the permittee to manage the WWPPP.

The WWPPP must be designed to address the anticipated volume and treatment needs for the wastewater generated during the well construction project. It shall include specifications for adequate Best Management Practices (BMPs) to treat the wastewater and guidance for the implementation, inspection and maintenance of the BMPs or controls used for the project. The Plan shall be written and implemented to adequately treat the wastewater before it enters streams, rivers, and lakes where is can create watery quality problems. As the work on the well project is about to begin, the local regional IDNR Field Services Office must be notified using the Field Office Notification Form (FON). For your convenience, the FON is now available in both Word and PDF formats.

The Well Water Pollution Prevention Plan shall take into account items that will influence how the wastewater is managed, such as:

  • The location of the well on the landscape;
  • the potential protections or limitations that the landscape may provide for natural wastewater treatment;
  • the potential quantities and anticipated qualities of wastewater that may be generated during each phase of the well construction or service work;
  • the best management practices (BMPs) used both on and off of the construction site to treat the wastewater;
  • the type of BMPs that will be applied to the site and strategic locations of all BMPs used;
  • any adjustments or changes made to the BMPs after the initial installation;
  • who inspects the BMPs, how often the inspections are performed, and what is found during the inspections;
  • and certification that all permittees and co-permittees fully understand what is required under GP6.

What types of resources are available?

Who should I contact if I suspect that a stream, river, or lake is being impacted by water well related wastewater discharge?

You should contact your local IDNR Field Services office if you suspect a body of water is being impacted by a well discharge. Please use the link below to find the nearest Field Office and their contact information.

Helpful web links:

For additional information about GP6 please contact:

Russ Tell - phone: 515-725-0462, russell.tell@dnr.iowa.gov
Iowa DNR Water Supply Engineering, 502 E 9th Street, Des Moines, IA 50319


Wendy Hieb - phone: 515-725-8405, wendy.hieb@dnr.iowa.gov
Iowa DNR NPDES Wastewater Permits, 502 E 9th Street, Des Moines, IA 50319, or by Fax: 515-725-8202