Onsite Septic Systems

When is a Septic Permit Required?

Onsite septic systems are reviewed and inspected by Environmental Health Specialists within the Benton County Environmental Health Division, however, the intake of onsite septic permits is performed by permit technicians in the Community Development Department.

To apply for onsite septic permits you will bring the permit application to 360 SW Avery Ave., Corvallis, OR 97333 and ask to see a permit technician. Open hours are typically between 8:30 am and 4:30 pm; please call 541-766-6819 and verify that the counter is open before coming in. However, if you have questions specifically about septic permits and what type of septic permit to apply for, please contact the Benton County Environmental Health Division at 541-766-6841 or visit their website.

There are many different types of onsite septic permits. The size of your onsite septic system is based on many factors, including the number of bedrooms being served by the onsite septic system and the soils and slopes on the property. All onsite septic permits are applied for using the Onsite Septic Application Packet.

The following types of building permits typically require a septic permit:
  • New dwelling
  • Replacement dwelling
  • Addition (increasing the number of bedrooms)
  • Remodel (increasing the number of bedrooms)
  • Commercial (new and capacity additions/alterations)

When building a new dwelling, replacing a dwelling, or adding bedrooms to a dwelling or accessory structure you will also need to complete the Onsite Septic Application Packet and submit it along with your building permit(s). Note: The property owner must sign the septic application packet.