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Marshall Fire: Onsite Wastewater Treatment Systems (OWTS)

Marshall Fire: Onsite Wastewater Treatment Systems (OWTS)

Onsite Wastewater Treatment Systems (Septic) After a Fire

If your tank and/or soil treatment area (leach field) were not damaged, it could be reused if the property is redeveloped. Sewer lines should be capped until ready to be reconnected. Consider having the tank pumped as part of your property clean-up.

The septic tank should be properly abandoned if the property is not redeveloped. Have the tank pumped and then filled with sand or gravel, remove it, or crush it and leave it in place.

When returning to your property, inspect the area around your septic system for signs of damage from fire and traffic from fire-fighting operations. If you feel your septic system may have been damaged, discontinue use until a licensed professional has inspected the system. The system may have been impacted if:

  • Plastic piping above ground has melted
  • Evidence of vehicle traffic in the area of the system
  • The raised system was in the direct line of fire (i.e., the grass on top is scorched)
  • There is damage in the area where the pipes enter the home

Check Your Septic Records

If you would like to have your system inspected you will need to hire a licensed, private contractor. You can find a list of these businesses on our website by searching for “Inspectors” in our Licensed Professional List.

*Please note that Boulder County Public Health (BCPH) does not require that your OWTS be inspected post-wildfire. The only time an inspection may be required is when the property title is transferred or if the existing OWTS is used for a non-residential purpose (e.g., adding bedrooms).

Repairs or Replacement of OWTS

Download a step-by-step guide to rebuilding an onsite water treatment system (septic)

Repair or Replacement of an OWTS

In some cases, repair or replacement of the OWTS may be required. If your system was damaged by fire or clean-up work, you are planning to increase the number of bedrooms in your rebuilt home, or planning to add an ADU or new use to the property, a new OWTS may be required. The following steps outline the OWTS permitting process as you navigate rebuilding.

  1. The first step is to hire an OWTS engineer familiar with Boulder County regulations. Your architect or builder may have a recommendation, or you can refer to our list of licensed professionals and search for “Engineer.”
    • If you are replacing a septic tank and no changes to use or bedroom counts will take place, you may not need an OWTS engineer. You can contact a licensed installer to replace your septic tank, and they can help you with what will be required. You will need to apply for a minor repair permit from Boulder County Public Health.
  2. Once you have your OWTS engineer onboard and plans for rebuilding (including bedrooms, auxiliary structures, and any additional, non-residential uses identified) the OWTS engineer can get to work reviewing the existing OWTS capacity and current condition of the system. From their they will determine if updates or replacement is necessary.
  3. Once the OWTS engineer has completed the OWTS design, you can apply for an OWTS permit with Boulder County Public Health.
  4. Once we receive the application, we will conduct a site inspection, review the plan, and issue an OWTS construction permit. Once this permit is issued any BCPH holds on the BP will be released. We will require the OWTS to receive final approval from BCPH prior to a CO being issued by Community Planning and Permitting.
  5. Once the OWTS has been installed by a licensed installer, they will contact BCPH to conduct a final inspection of the OWTS.
  6. Once the installation is approved we will issue a Use Permit (there is no fee for this) and release the hold on the CO for the structures.

If you have questions about your specific needs please contact us at or at 303.441.1564 and leave a message including your address. We have staff on call Monday through Friday from 8 to 4:30.

Resources for Septic System Owners

BCPH has compiled helpful information to provide guidance and answer questions about Marshall Fire impacts on septic tanks and wastewater:

Learn More

Residents who have questions or concerns about the impacts of the Marshall Fire, and subsequent recovery effort, can get more information here:

As new information develops, we will continue to add resources to this page.

Contact Us

SepticSmart Program

Main: 303-441-1564
Submit a question


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