Dock Maintenance

Cleaning and Maintaining Docks

Washing docks (or wharves, piers, floats, and boat ramps) can result in the discharge of dirt, bird feces, soaps, and detergents that can be toxic to aquatic life. Dock cleaning and repair during the regularly scheduled lake drawdown  is preferred to preserve Lake Oswego’s water quality.

Surface Preparation

  1. Scoop and collect debris and bird feces.
  2. Sweep, capture, and dispose of debris from the dock as solid waste.
  3. Sweep or vacuum docks to minimize the need for chemical cleaners.


  1. If debris or washwater can enter the lake or the stormwater system, temporarily block the drains and pump the water to the wastewater cleanout.
  2. Place a tarp over exposed soil and plant vegetation.
  3. Spot clean the deck with water (no soap) and a coarse cloth.
  4. If a cleaner or detergent is needed, mix it in a bucket on land and use it only to scrub the areas that need extra attention.  Start with vinegar and baking soda and move to other options as needed. Dump washwater into the wastewater cleanout.
  5. If harsher cleaning products are needed, mix them on land and hand apply with a rag as needed.  Keep cleaners in sealed containers on land.  Remove residual grease by hand using degreasers or absorbent material - do not allow it to enter the lake or stormwater system.   The use of petroleum distillates, chlorinated solvents, and ammoniated cleaning agents is prohibited. 

Dock Cleaning and Washwater Disposal

  1. Pressure wash using light pressure and minimal soap. Excessive pressure may loosen paint flakes or other material into the lake which is prohibited.  Collect washwater and dispose of it in the wastewater cleanout.
  2. Use non-abrasive methods and tools that for cleaning areas near creosote or treated wood.   Place removed material into the trash bin or yard debris bin as appropriate. 

It is a violation (subject to a minimum $1,000 fine) to dump or discharge anything to the lake or stormwater system during dock cleaning and repair.


Source: WA Dept of Ecology 2019 Western Washington SWMM