Foam docks and blocks law

New environmental protections will reduce plastic pollution in Washington’s waters. Beginning in 2024, polystyrene foam used in docks, floating blocks, or overwater structures must be fully enclosed in a shell made of plastic (at least 0.15-inches thick), concrete, aluminum, or steel.

  • Polystyrene foam must be fully enclosed in a shell made of plastic (0.15 inches), concrete, aluminum, or steel. 
  • Exposed polystyrene foam and foam wrapped in plastic film is prohibited in new dock repairs and construction.
A small wooden dock on a beach with block floats made of expanded polystyrene, a material now banned in Washington for dock construction.
A chunk of expanded polystyrene left on the ground, with dirt lining the small foam balls as a sign of its long time in the elements.

How this new law will protect Washington’s waters 

When foam blocks are installed to keep docks and overwater structures afloat the foam can break down easily if it’s not protected, quickly becoming a microplastic pollutant.

  • A short-lived material with long-term alternatives: After investing money and effort into a dock repair, it’s easy for foam to break apart from collision or become water-logged, putting resources to waste. Fully enclosed foam in hard shell materials is widely available and commonly used by dock builders. 
  • Risk to fish and aquatic ecosystems: When foam breaks down into bite-size pieces, aquatic animals can mistake it for food, endangering fish, birds, and crustaceans.
A plastic-enclosed floatation block supporting an overwater structure.

When will the new law be applied to docks, blocks, and overwater structures?

Beginning Jan. 1, 2024, expanded or extruded polystyrene foam used in installation or existing upgrades for docks, blocks, and overwater structures must be fully enclosed in a protective shell.

Allowed and banned overwater structures

Polystyrene foam must be fully enclosed in a shell made of plastic (0.15 inches), concrete, aluminum, or steel.

Exposed polystyrene foam and foam wrapped in plastic film is prohibited in new dock repairs and construction.

Frequently asked questions


Additional resources

Need a permit for the work you’re doing near water? Here is information about the types of permits typically required for work done in or near water for structures like docks, buoys, bulkheads, dredging, culverts, etc.