The Contractors State License Board (CSLB) issued an industry notice on July 9, 2026, reminding California contractors of the statutory requirements governing treated wood waste (TWW).
The advisory, published as bulletin #26-03, outlines compliance resources for professionals who handle, store, or transport pressure-treated lumber. Because fence contractors regularly extract and replace weathered posts, rails, and retaining walls, these waste-management standards directly affect their daily field operations.
Statutory Outreach and Resources
Under Assembly Bill 332, passed in 2021, the wood-preserving industry must collaborate with state regulators to educate businesses, residents, and waste haulers on proper disposal protocols. To meet this mandate, the Western Wood Preservers Institute (WWPI) maintains an information portal at TWWDisposal.org.
The website operates in both English and Spanish, providing guidance on:
- Identifying treated wood waste
- Handling and storage protocols
- Labeling requirements
- Transportation rules
The portal also features a directory of landfills and transfer stations authorized to accept treated wood waste, alongside a list of registered waste haulers.
Generator Thresholds
Compliance obligations depend on the volume of waste a contractor produces. The guidelines divide businesses into two tiers based on weight:
- Generators: Contractors handling typical project volumes.
- Large Quantity Generators: Contractors who generate 10,000 pounds or more of treated wood waste. This higher tier requires adherence to stricter operational guidelines detailed on the WWPI website.
The CSLB distributed this reminder pursuant to subdivision (e) of Health and Safety Code Section 25230.15. For definitive regulatory text and authorized disposal maps, contractors should consult the Department of Toxic Substances Control (DTSC) or the WWPI portal directly.