(1) Facility plans shall contain procedures for notifications for spills to ground and to permeable secondary containment that threaten to impact waters of the state.

(a) All spills are considered reportable spills except;

(i) Spills which are known to be less than forty-two gallons that do not impact surface or groundwater.

(ii) CERCLA releases.

(iii) On-facility air releases to the atmosphere only.

(iv) Releases from underground storage tanks regulated under chapter 173-360A WAC.

(v) Preexisting sources of releases identified as RCRA solid waste management units.

(vi) Spills contained within areas controlled by NPDES permitted systems that are not likely to threaten groundwater and do not exceed applicable federal reportable quantities.

(b) A spill is considered to have not impacted ground if it occurs on a paved surface such as asphalt or concrete. A spill to dirt or gravel is considered to have impacted ground and is reportable.

(2) Plan holders must also include procedures in their plan to address spills of an unknown volume. When addressing a spill of an unknown volume, plan holders shall use best professional judgment and may consider the following circumstances in determining when to make notifications:

(a) Whether the spill is ongoing; and

(b) Whether the spill is located in an area that is adjacent to waters of the state or where there is a pathway to waters of the state, and the environmental conditions, such as rain events, or known shallow groundwater make impacts to waters of the state likely.