Construction Stormwater General Permit

Do I need coverage?

Many construction sites will need to apply for coverage under the CSWGP. Construction site operators are required to be covered if both of these apply:

1. Your construction project disturbs land* through clearing, grading, excavating, or stockpiling of fill material.
   • Sites that disturb one acre or more.
   • Sites that are smaller than one acre that are part of a larger common plan of development that will ultimately disturb one acre or more and discharge stormwater to surface waters must apply for a permit.
   • Sites of any size discharging stormwater to state waters (Waters of the State) that we determine to be a significant contributor of pollutants.
   • Sites of any size that we reasonably expect to cause a violation of any water quality standard.
2. There is any possibility that during construction, stormwater could run off your site or enter a conveyance system that leads to surface waters. In almost every case it does. If the location of your site poses no possibility that rainfall or snowmelt could leave the site or enter a waterway, you do not need a permit.

*Count the cumulative acreage of the whole project, whether it's single or multiphase. Include off-site disturbance acreage from support activities related to the construction site. This applies if your project is a portion (less than one acre) of a larger project planned over time.

To apply for new permit coverage

For standard permit coverage, you must apply for a permit at least 60 days before discharging stormwater from your construction site. We try to issue coverage 45 days after receiving a complete application (a minimum of 30 days is required for the public comment period). For project sites with existing known contamination, we recommend you apply at least 90-120 days prior to stormwater discharge to allow for additional staff review time.

You will need to set up an account to use our WQWebPortal to apply for coverage:

• Notice of Intent (online application for new permits, will require SAW account sign in)

Was your permit covereage revoked?

Coverage renewals were required 180 days before the general permit expired. Renewal applications should have been submitted by July 3, 2025.  If your permit coverage has been revoked and you need permit coverage use the links above to submit a new NOI.

To expedite application processing, after you apply online please scan or take a photo of all permit forms and email them to our resource mailbox at: ecyrewqianoi@ecy.wa.gov. Also, you must mail the original, signed documents to:

Water Quality Program
PO Box 47696
Olympia, WA 98504-7696

We are currently emailing all coverage documents and permit related information to the permittee on file. 

If you have any questions, contact us at the email addresses below.

We try to process the forms below within 45 days of receiving them.

• Impaired water new discharge
• Transfer coverage (Transfer of Coverage)
• Change in activity status
• Modification/update
• Terminate coverage (Notice of Termination)

You will need to set up an account to use our WQWebPortal to submit a DMR:

• Submit a DMR (will require SAW account sign in)
• Site inspection form template
• Request for chemical treatment
• Stormwater Pollution Prevention Plan (SWPPP) template
• Stormwater manuals

Need more help? See our further resources.

• Rainfall erosivity factor calculator
• ​Erosivity waiver request form 
• Central Basin map

• Submit Discharge Monitoring Reports (DMRs) using WQWebPortal
• Permit and Reporting Information System (PARIS)
• Find a Certified Erosion and Sediment Control Lead (CESCL)
• Find a Lab
• Report an environmental issue (ERTS)

• Stormwater permittee guidance
• Sampling guide for construction sites
• Stormwater Monitoring
  • Sampling for Construction Stormwater Video (YouTube)​

• Stormwater Manuals

• Permit requirements guide