Simpson® Soft Wash Systems Built for Real Work.

Soft washing is a low-pressure cleaning method (typically under 300 PSI) that uses specialized detergents, often including sodium hypochlorite (SH), to kill mold, mildew, algae, and bacteria on roofs, siding, and other exterior surfaces. Instead of relying on high pressure to blast away dirt, soft washing uses chemistry to break down organic growth and rinse it away without damaging shingles, paint, stucco, or landscaping.

Pressure washing uses high PSI (often 2,000-4,000+) to physically strip dirt and grime from surfaces, which works well on concrete and hard surfaces but can damage roofing, siding, and painted wood. Soft washing uses low pressure (up to 300 PSI) combined with SH-based cleaning solutions to kill the root cause of staining and produces a longer-lasting clean on roofs and siding without the risk of surface damage.

For residential house washing or starting a soft wash business, an 8 GPM system is typically enough. Crews handling a mix of residential and light commercial work should look at a 10 GPM system. For roof cleaning, two-story homes, and high-volume commercial accounts, a 12 GPM soft wash system provides the flow rate needed to keep up with larger surfaces and multiple hose lines.

Yes. Every Simpson soft wash system on this page uses a chemical-ready diaphragm or gear-drive pump (Comet P40 or Comet BPX25) built to handle sodium hypochlorite and other soft wash detergents, along with a stainless steel frame that resists corrosion from SH exposure.

Simpson soft wash systems carry a 10-year warranty on the frame, a 3-year warranty on the engine, and a 2-year warranty on the pump, backed directly by All Parts as part of the FNA Group family.

Yes. As part of the FNA Group family, the same parent company that owns Simpson, All Parts stocks factory OEM parts for Comet P40 and Comet BPX25 pumps along with engines and frame components, and provides direct technical support for soft wash equipment.