Washington Mobile Sources regulations & environmental compliance analysis

Washington Mobile Sources: What you need to know

Governing Law and Regulations

Vehicle inspection and maintenance (I/M): Washington Administrative Code (WAC) 173-422A-010 to 173-422A-500

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Applicability: WAC 173-422A-020, WAC 173-422A-030, and WAC 173-422A-060

Inspection schedule: WAC 173-422A-030 and WAC 173-422A-040

Emissions testing areas: WAC 173-422A-050

Emissions standards: WAC 173-422A-100 to 173-422A-300

Automobile emissions standards:

Antitampering requirements: WAC 173-421-010 to 173-421-100

Low Emissions Vehicle (LEV) standards: WAC 173-423-010 to 173-423-150


Oxygenated gasoline program: WAC 173-492-010 to 173-492-100

Regulatory Agency

Washington Department of Ecology (WDOE) Air Quality Program

See ADDRESSES & CONTACTS for addresses and telephone numbers.

See national section for basic information and federal regulations.

Comparison: State v. Federal

Rules. Many of the federal mobile source emissions standards are applicable and in effect in Washington, and the state adopted the California low emissions vehicle (LEV) standards. Washington administers its own vehicle inspection and maintenance program and a seasonal oxygenated gasoline program.

Administration and enforcement. WDOE's Air Quality Program administers and enforces the state mobile source requirements.

State Requirements


WAC 173-422A-010 to 173-422A-500

Emissions controls required by the state and federal government are designed to reduce emissions from motor vehicles. However, the effectiveness of the controls is substantially reduced through deterioration, maladjustment, and tampering. The Washington motor vehicle emissions testing program is intended to encourage appropriate vehicle maintenance and repairs in order to reduce air pollution.


WAC 173-422A-020, WAC 173-422A-030

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More on this topic:

Governing Law and Regulations
Regulatory Agency
Comparison: State v. Federal
State Requirements
Additional Guidance

Washington Mobile Sources Resources

Type Title
Forms Stage II System Decommissioning Notification Form
See all Mobile Sources Resources