GP9 - Dewatering & Geothermal

Back to top

NPDES General Permit 9 for Dewatering Activities & Residential Geothermal Discharges

On July 1, 2018, the Iowa DNR issued a new general permit to authorize discharges from the following activities:

  • Excavation dewatering associated with construction activity
  • Temporary groundwater dewatering to facilitate construction activity
  • Residential open-loop geothermal heating and cooling systems

General Permit 9 (GP9) was reissued on July 1, 2023.

GP9 covers dewatering discharges to surface waters of the state and to the ground surface. Discharges from geothermal systems that do not reach navigable waters are already exempted by rule from obtaining operation permits. Therefore, only discharges to navigable waters from residential geothermal systems are authorized by GP9.

Back to top

GP #9 Renewal

The DNR is hosting an informal stakeholder meeting on March 12, 2026, regarding the proposed five-year renewals of NPDES General Permits #8 and #9 (GPs #8 and 9). The purpose of this meeting is to accept comments and answer questions on possible changes to the GPs. The DNR is specifically seeking comments on the clarity, feasibility, and potential impact of the proposed changes. Formal rulemaking to renew GPs #8 and #9 is expected to begin in mid-2026.

The meeting will be held on Thursday, March 12 at 11:00 am.  The meeting is open to the public and will be held virtually via Google Meet.

  • Video call link: https://meet.google.com/gkb-qpgk-kmc
  • Or dial: â€ª(US) +1 424-338-0161 PIN: â€ª862 188 632#
  • More phone numbers: https://tel.meet/gkb-qpgk-kmc?pin=6531727035955

Questions and comments regarding the draft renewals or the meeting may be directed to Wendy Hieb at wendy.hieb@dnr.iowa.gov. Comments will be accepted until Thursday, March 19th.

Redline-strikeout version of the draft renewal of GP #9 (2026-2-19).pdf (505.49 KB) .pdf

Back to top

General Permit & Helpful Documents

Please use the links below to view GP9 and documents intended to assist you in navigating the permit requirements.

General Permit 9 – effective July 1, 2023 (380.08 KB) .pdf

Several documents have been developed to help people determine what permit requirements are applicable in a given situation.

Back to top

Coverage Under GP9

Most permittees will be automatically covered under GP9. However, some permittees will need to submit an electronic Notice of Intent for Coverage (eNOI). To determine if you need to submit an eNOI, please refer to the documents linked above. If you need to submit an eNOI, please proceed to the NPDES Databases page.

A few permittees will need to complete an Antidegradation Document as part of the the electronic Notice of Intent. For more information on the antidegradation requirements, please see the Water Quality Standards Antidegradation page.

Back to top

Effect of GP9

What GP9 does:

  • Authorize temporary and limited discharges that can meet water quality standards.
  • Authorize certain discharges that are not temporary and limited but that are approvable under Iowa’s Antidegradation Implementation Procedure (781.09 KB) .pdf .
  • Provide a permit shield to authorized discharges.
  • Establish eligibility requirements and best management practices to ensure protection of water quality.
  • Reduce the number of permittees required to pursue individual permits.
  • Greatly reduce the amount of time needed to obtain permit coverage for most permittees.

What GP9 does NOT do:

  • Authorize discharges that will cause violations of water quality standards.
  • Authorize discharges from groundwater remediation systems.
  • Authorize discharges to Outstanding Iowa Waters or state-owned lakes.
  • Establish burdensome notification requirements.
  • Require fees.
  • Eliminate the department’s ability to require a discharger to apply for an individual permit.
  • Eliminate a discharger's ability to apply for an individual permit.
Back to top

References

Back to top