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NPDES Permit Development Tools

This page features tools and document templates DEQ permit writers use to develop individual National Pollution Discharge Elimination System (NPDES) permits. Both the permit development tools and templates help ensure consistency in permit writing and guide facility and receiving water characterizations necessary to establish pollution discharge limits and permit conditions.  Additionally, DEQ has developed a wide variety of modeling tools used to identify the potential impact on water quality.  The template and development tools are available on the DEQ website so that permit holders, engineering consultants and the public can have a better understanding of the permit development process.


For each permit, DEQ uses a series of water quality models to determine if the facility has the reasonable potential to cause or contribute to the exceedance of a water quality standard. Generally, permit development for a larger and more sophisticated facility is reflected in depth and extent of the modelling efforts.  For this purpose, DEQ maintains the following guidance documents and spreadsheets:



Most permits will be developed using the above workbook. For RPA spreadsheets specific to industrial facilities, please contact Erich Brandstetter, 503-229-5047.


RPA for Ammonia calculation workbook, Revision 2.4
Please contact Stephen Schnurbusch, 503-378-8306 for questions or to provide edits or feedback.


RPA for Chlorine calculation workbook, Version 4.0
Please contact Stephen Schnurbusch, 503-378-8306 for questions or to provide edits or feedback. 

Copper Biotic Ligand Model

Copper Biotic Ligand Model to calculated water quality standard. 
Contact Copper BLM Implementation Group to discuss site specific implementation of standard and RPA process.

Dissolve oxygen


RPA for pH calculation workbook, Revision 1.3
Please contact Stephen Schnurbusch, 503-378-8306 for questions or to provide edits or feedback. 


Permit templates 

DEQ maintains a series of domestic and industrial permit templates for both the NPDES and WPCF programs. There are also templates for the supporting Fact Sheets.  Over time, DEQ expects to develop additional versions tailored to other parts of the water quality program, regions and specific cases.
The permit templates are a guide for permit writers as they incorporate new and updated policies, rules, and standards into official renewed and issued permits. DEQ provides these to show what permit writers will use during permit development.
We will post new versions of the NPDES permit development tools as soon as they are available.

Features of the permit template include:

  • Highlighted instructions. These call attention to language that may need to be tailored for particular permits.
  • Links to various documents developed to inform the permit development process.
  • The templates are regularly updated to reflect changes in DEQ policy and water quality criteria.


  • Please contact Jeff Navarro, 503-229-5257 if you have any questions regarding the content or use of templates.
  • Questions and comments of the water quality models may be submitted to Erich Brandstetter, 503-229-5047

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