Tertius

Your gateway to doing business in the District.

  • Required for certification
  • Market Presence
  • Reporting and Visibility
  • Support for all Disciplines
  • 100%

    of certified inspection submitted through Tertius since 2022
  • 75%

    of customers use third-party regulatory code inspection services 100% for special inspections
  • Reduces reporting errors and provides access to DOB and your Customer.
  • 4+

    Disciplines that agencies may provide services. Seen by agencies offering multiple disciplines

Existing agencies

Already certified? Login to manage your agency profile and inspections.

Log in to TPIA

New agencies

New to the program? Become a certified third-party agency in the District.

Register

How it works

  1. 1.

    Register as an agency or professional

    Create a Tertius account to begin the application process.

  2. 2.

    Complete Profile

    Add all the required information, contact, documents, disciplines, and certifications.

  3. 3.

    Receive DOB approval

    DOB will review your submission and approve. Or request additional information.

  4. 4.

    Work in the District

    Once approved, you can work as a certified third-party agency in the District.

  5. 5.

    Keep your profile up to date

    Maintain accurate information to ensure continued visibility and compliance

Need more information?

Contact Us