State agencies urge consultants to upload paired building data to GeoTracker to build California-specific attenuation factors

State Water Board staff leading the GeoTracker initiative said California needs more paired building and subsurface data submitted electronically to develop or validate California-specific screening attenuation factors. Tina Yeris, the dataset team lead, told the workshop that GeoTracker currently holds building information for about 135 open cleanup cases statewide while the board identifies more than 5,000 open cleanup cases (excluding UST petroleum cases) that could add representative data by climate zone, building design and age. She said the goal is to evaluate whether one or more California-specific attenuation-factor scenarios (for example, residential or commercial building designs) are warranted, or whether the U.S. EPA national attenuation recommendation is applicable. What the agencies are collecting: paired data types to be submitted include indoor air, sub-slab soil gas, soil gas, outdoor air, crawlspace and sewer gas, plus groundwater and precise sample location (latitude/longitude). Additional building-specific attributes — foundation type, area, HVAC operating status at the time of sampling and building age — are voluntary but “critical,” Yeris said, because they help explain how physical attributes influence attenuation. Yeris described a projected timeline: continued outreach and training in the near term, a GeoTracker BI (building information) public workshop tentatively in early 2026, finalization of study evaluation criteria after that workshop, and an initial evaluation of the assembled dataset tentatively mid-2026. She urged responsible parties, consultants and accredited laboratories to upload their VI data and building attributes to accelerate the evaluation. Why it matters: CalEPA staff said national datasets have limited representation of California’s warm-climate, slab-on-grade building stock and that a state-specific dataset will improve screening and reduce unnecessary indoor sampling or conservative assumptions in redevelopment scenarios. Ending: Staff said agency teams will publish resources (upload checklists and a public dashboard of current data needs) and provide GeoTracker training; they invited attendees to a BI database breakout session to discuss data upload details.