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Updating underground storage tank regulations

Washington's Underground Storage Tank regulations are known as the "UST rule." 

On July 18, 2018, we repealed the existing rule, Chapter 173-360, and adopted a new rule, Chapter 173-360A.  The new rule modifies and replaces the repealed rule. The rule is intended to prevent the release of petroleum or other hazardous substances from UST systems, and ensure that any release is detected and cleaned up.

Washington has a federally-approved Underground Storage Tank (UST) program. This means that state law, not federal law, applies to regulated UST systems in the state (except for those on Native American lands).

Who is affected?

The changes to the UST regulations may impact people who:

  • Own or operate UST systems.
  • Provide services to owners and operators.
  • Deliver product to, or collect waste oil from, UST systems.
  • Provide pollution liability insurance for UST systems.
  • Conduct training for operators of UST systems.

Purpose of the program

The UST program is one of Washington’s most important pollution prevention programs.  Under this program, we regulate and periodically inspect about 9,000 tanks at over 3,300 fueling and other facilities throughout the state. This prevents releases of petroleum and other hazardous substances into the environment and ensures any releases are detected and cleaned up. 

  • Historic releases from underground storage tanks constitute about half of all known contaminated sites in Washington.
  • The UST program has significantly reduced the number of releases–from several hundred to less than fifty each year. Those that do occur are much less severe.
  • Each release that’s prevented by the UST program is another contaminated site that doesn’t require cleanup, which is costly for owners and hinder community and economic redevelopment.

Learn more about the UST program

Why did we update the UST regulations?

In October 2015, the Environmental Protection Agency (EPA) adopted changes to the rules governing the federal UST program (40 Code of Federal Regulations [C.F.R.] Part 280) and state program approval (40 C.F.R. Part 281). These are the first major changes to the federal rules since 1988.

The changes enact the requirements in the UST Compliance Act of 2005, add new operation and maintenance requirements for UST systems, and establish requirements for certain types of UST systems that were deferred in 1988. States with federally-approved programs must incorporate the changes by October 2018 to maintain program approval.

Learn more about changes to federal requirements

Summary of changes to regulations

We repealed existing Chapter 173-360 WAC and adopted new Chapter 173-360A WAC. The new chapter modifies and replaces the repealed chapter. The UST regulations were modified to:

  • Incorporate federal rule changes needed to continue the UST program, as specified in 40 C.F.R. Parts 280 and 281 (such as new operation and maintenance requirements for UST systems, and requirements for field-constructed tanks and airport hydrant systems).
  • Integrate changes to the state statute that authorizes the program, Chapter 90.76 RCW (such as licensing requirements for UST systems).
  • Update other requirements governing the program (such as UST service provider requirements).
  • Streamline rule requirements, improve rule clarity, and improve consistency within the rule and with other state and federal laws and rules (such as reorganizing the rule).
View the new UST regulations, and learn more about the changes and training opportunities