Pressure washing costs in Boise

Plain water gets a pass in Boise that soapy water doesn't. The city's stormwater guide for non-stormwater disposal, dated December 2019 and written for businesses and for individuals cleaning property, lists routine washing of a building's outside without detergents among the discharges it allows. Street and pavement wash water is on the same list, as long as no detergent is used and no toxic or hazardous material has spilled there, unless the spill has been cleaned up.

Soap changes the answer. For outside cleaning with no hazardous materials, the guide says wash water with soap of any kind isn't allowed into storm drains.

The guide also asks for less water, and it names high-pressure washing as one way to use less. If oil, grease or sediment is around, it wants filters or absorbent booms at the drain inlets, and no visible sheen on whatever reaches the drain. Hot-water, high-pressure cleaning such as steam cleaning that drains to a storm drain has to meet every one of those controls.

The drain at your curb probably isn't the city's. Boise says street drains are the responsibility of the Ada County Highway District, and in flood-irrigated areas drainage falls to irrigation or drainage districts or local water users associations.