Soft washing is a low pressure cleaning process commonly used to safely treat and remove organic matter: mildew, bacteria, algae, fungus, moss, lichens in addition to dirt, grime and spiderwebs. Soft washing originated as an alternative to power washing where high pressure can cause damages. The application is achieved from low pressure dedicated pumps where measurements of commonly used products, mainly sodium hypochlorite (bleach) and detergents can be preciously metered and applied. Soft Washing continues to evolve. Pumps now available producing more pressure than original electric diaphragm pumps, allowing solution to be safely applied at further distances and adding increased rinsing volume. (Booster pumps, air diaphragm, and gas powered diaphragm pumps. Metering systems, allowing precise metering and mixture of sodium hypochlorite (bleach), detergent and water. Color marking detergents available to show where mixture has been sprayed, reducing usage while assuring proper coverage. Remote systems to switch between applying solution and rinsing. Neutralizing agents to aid in reducing damages that can be caused by chemicals. Soft washing has drastically changed the proficiency and safety of cleaning structures and roofs.  
Soft washing is a cleaning method using low pressure and specialized solutions (typically bleach, water, and sometimes a surfactant) to safely remove mildew, bacteria, algae and other organic stains from roofs and other building exteriors. It is so named to differentiate the method from power washing. The Asphalt Roofing Manufacturers Association recommends low-pressure bleach or detergent assisted washing as the preferred method for cleaning asphalt roofs in order to prevent damage to the shingles.
Soft washing is using an electric agricultural sprayer to apply a water-based, biodegradable disinfecting cleaning solution to kill the mold, mildew, bacteria, algae, fungus, moss and more on exterior home and building surfaces.
Soft washing Equipment is distinctly different than power and pressure washing equipment. The electric diaphragm pump applies the cleaning solution at 40-80 PSI. The equipment used for soft washing may also have telescoping handles so that the cleaning solution can easily reach roof eaves, upper story windows, and other such areas, without this added pressure. 
- Clean by Gene
- "The Concepts Behind Soft Washing". eClean Magazine. Retrieved 2017-06-29.
- "ARMA - Asphalt Roofing Manufacturers Association | Algae & Moss Prevention and Cleaning for Asphalt Roofing Systems". www.asphaltroofing.org. 2016-09-23. Retrieved 2017-06-29.
- "What is Soft Washing". Ann Arbor Power Washing Pros. Retrieved 2018-08-23.