NPDES General Permit #8 for Hydrostatic Testing, Tank Ballasting, and Water Lines

Note: This is a PROPOSED GENERAL PERMIT. No discharges are authorized under this permit at this time.

The Iowa DNR is developing a new general permit that is intended to authorize discharges from the following activities:

  • Hydrostatic testing of pipes, lines, tanks, and associated equipment.
  • Ballasting of underground storage tanks during installation.
  • Disinfection, flushing, and testing of potable water lines.

Proposed General permit #8 (GP8) would cover discharges to surface waters of the state and to the ground surface. Certain discharges from potable water lines in MS4 cities may already be authorized under the city’s MS4 permit.

Permit, Rulemaking, and Helpful Documents

Please use the links below to view proposed General Permit #8, the changes made to GP8 in response to public comments, and the permit rationale.

Proposed General Permit #8 – December 22, 2017

Proposed General Permit #8 Markup in Response to Public Comment - March 26, 2018

Rationale for General Permit #8

Please use the links below to view the rulemaking documents associated with GP8.

Notice of Intended Action for EPC - General Permits #8 & #9

General Permit 8 & 9 Final Rule - March 26, 2018

General permit 8 & 9 Responsiveness Summary - March 26, 2018

Two documents have been developed to help people determine what permit requirements are applicable in a given situation. The GP8 Matrix is a series of yes/no questions. As you answer each question, you will be directed to the next applicable question. You may prefer this if you are a linear thinker or like flow charts. The GP8 Requirements Summary has all the permit requirements laid out in one document, so you can easily find the requirements for your situation. You may prefer this if you are a visual thinker, or if you wish to compare requirements among different situations.

General Permit #8 Decision Matrix

General Permit #8 Requirements Summary

GP8 Justification:

Currently, people conducting discharges that would be authorized by GP8 can either pursue an individual permit or discharge illegally. Obtaining an individual permit requires an investment of time and money that is disproportionate to the impact these discharges usually have on the environment. Not only is discharging without a permit illegal, but the discharges may occur without environmental controls. DNR receives many requests for guidance from those who are interested in avoiding negative environmental impacts.

Proposed General Permit #8 will benefit dischargers by providing them a permit shield without the time and cost of obtaining an individual permit. Unlike individual permits, no fees are associated with GP8. It also provides dischargers with guidance for minimizing the impact of these discharges on water quality. This permit will benefit the environment by providing requirements and guidance for conducting these discharges in a manner that will avoid negative impacts on water quality. This permit will benefit DNR by providing a mechanism to authorize these discharges using very little staff time, which can then be spent on higher-risk discharges.

Effect of GP8:

What GP8 will do:

  • 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.
  • 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 GP8 will NOT do:
  • Authorize discharges that will cause violations of water quality standards.
  • 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.


General permits must be adopted into rule and discharges authorized by the permits must be added to the list at 567 IAC 64.3(4).

The Notice of Intended Action for Proposed General Permits #8 and #9 was approved by the Environmental Protection Commission on January 17th. The Notice was published in the Iowa Administrative Bulletin on February 14th as ARC 3625C.

The Administrative Rules Review Committee (ARRC) took no action on the rules at its meeting on March 9, 2018. The final general permits and rules were presented to the Environmental Protection Commission (EPC) at their meeting on April 17, 2018, and published in the Iowa Administrative Bulletin as ARC 3786C on May 9, 2018.

Stakeholder Input:

Three public hearings were held in March 2018, and written comments were accepted until March 19th. The Responsiveness Summary addressing all of the comments regarding GP8 is included to the left with the other General Permit 8 & 9 rulemaking documents.

More information:

For more information on this permit, please contact Julie Faas at 515-725-8409 or