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NPDES General Permit #8

for Hydrostatic Testing, Tank Ballasting, and Water Lines



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.

The permit 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.

Draft General Permit #8 – October 12, 2017


Currently, people conducting discharges that would be authorized by the permit 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.

This permit 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 GP#8.  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.

What this permit 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 this permit 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.  Most importantly, the discharges authorized by the permit must be added to the list at 567 IAC 64.3(4) and the permit must be added to the list of general permits at 567 IAC 64.15.  Other rule changes may also be necessary.  This page will be updated as rulemaking proceeds.

Stakeholder Input:

DNR has held three stakeholder meetings on the draft permit.  The presentation and notes from the stakeholder meetings are linked below.

Presentation from 5-20-2015 Stakeholder Meeting for Proposed GP #8
Notes from 5-20-2015 Stakeholder Meeting for Proposed GP #8 Notes from 5-3-2016 Stakeholder Meeting for Proposed GP #8

More Information:

For more information on the development of this permit, please contact Julie Faas at 515-725-8409 or julie.faas@dnr.iowa.gov.