With any element in your landscaping, whether it’s a bed of perennials, a stamped concrete driveway or a lush green lawn, your hope is for its longevity. While treated wood (TW) may seem like a helpful choice for weathering climate vulnerability on your property, its cons may outweigh the pros. Whether you are a homeowner, contractor, transporter or simply helping out a friend, application of the new TWW regulations will affect you differently, so use this article as a primer before doing some additional research.

What is TWW?

TWW refers to any lumber that has been chemically treated to protect against rot and insects. The most common type of TWW, and a name you may be familiar with is, “pressure treated” wood. The process entails placing the wood inside a depressurized tank to remove any air and then infusing it with chemical preservatives. Pressure treated wood is frequently used in areas with high moisture or insect populations like decks, picnic tables or fence posts.

What Changed?

As of December 31, 2020, a long-standing CA State Health and Safety Code (CA-HSC 25150.7) expired. This expiration means that all TWW is considered hazardous and must be disposed at a Class I hazardous waste landfill. Some of you may have already ran into this frustrating situation where you go to dispose of wood waste at the dump and you are turned away. For others, my hope is that this article can help save you some time and money by being prepared and educated on how to handle your TWW.

How do I know if my wood has been chemically treated?

TW can often be recognized visually. According to the DTSC fact sheet, some signs to look for include:

  • Treated wood end tag (with information regarding the preservative used)
  • Wood manufacturer stamp codes
  • Indentations on the surface of the wood
  • When cut, staining is visible around the perimeter only
  • Discoloration (e.g. green or dark brown appearance)
  • Odor Treated wood may also have an end tag

How do I dispose of TWW?

Instead of your usual local dump, TWW can only be dropped at an authorized hazardous waste landfill. As of March 2, 2021, the DTSC has posted an updated list of landfill locations that will accept TWW, which can be found here. Many of these landfills have different acceptance requirements, like a pre-approved waste profile, so it is recommended to call ahead. Currently, there are no dump sites in Santa Cruz County. There are some locations in San Jose, but again, call first to ensure you are properly prepared.

Construction and demolition costs to increase

Due to the changing regulations, disposal fees are skyrocketing for contractors. Most have to transport the waste much farther which comes with increased costs. Be sure to inquire with your contractor during the interview regarding their company’s updated policies on TWW as this is a newly implemented order, and to budget appropriately for your next remodel.