How to Use a Pressure Washer with Detergent

Cleaning with maximum effort is only effective if the correct supplies are used for the task. When pressure washing alone is insufficient, detergents can significantly ease the removal of stubborn dirt and stains. Detergents and soaps loosen tough grime, so the pressure washer can clear it away for a clean, new look. 

Various types of cleaning detergents are designed for specific tasks. It is essential to use only detergents labeled for pressure washer use and to avoid any products containing bleach, as bleach can damage the pressure washer. 

Concentrated vs Ready-To-Use Detergent 

Detergents are available in both concentrated and ready-to-use formulas based on the intended use. Ready-to-use detergents can be added directly to a detergent tank as-is, while concentrated detergents must be mixed with the appropriate amount of water to achieve the proper ratio. 

If detergent is not used often, it may be beneficial to purchase ready-to-use formulas so they can be used immediately from the container without mixing ratios in a separate bucket or tank. 

Types of Pressure Washer Soap by Application 

Different surfaces require different detergents, so choose a formula specifically designed for the application. 

For example, a specific concrete detergent is required to remove deep-down oil stains from a garage or driveway. Using that same detergent on a car could potentially strip the paint. 

Vehicle detergents are also specialized. There are specific detergents for boats, others for cars, and formulated solutions for motorcycles and RVs. The dirt, road salt, and insects removed from a truck require different treatment than the water and algae deposits cleaned from a boat. Additionally, the exposed components of a motorcycle may require a different solution than the decals and compartments on an RV. 

House cleaning detergents are formulated to remove deeply embedded dirt from siding without damaging it or fading the color. However, when cleaning a deck or fence, a detergent designed specifically for those surfaces should be used to remove dirt and grass stains from the wood. 

General-purpose detergents are also available for use on multiple surfaces. While these are not designed to perform as well in specific applications, options like degreasers, general-purpose soaps, and full soap kits can save users from buying products individually. For best results, it is recommended to use detergents designed for each specific application, though a general-purpose cleaner is useful for large jobs where frequent detergent changes are not desired. 

How to Clean Using Detergent 

Most modern pressure washers feature onboard detergent tanks. These soap dispensers make cleaning much easier by allowing the pressure washer to be moved without the need to relocate a bucket. Units without these tanks require a detergent hose to be inserted into an external bucket. 

After the detergent tank is filled, the valve must be turned to "On", so the detergent is applied during spraying. The user must switch to a low-pressure detergent nozzle, as high-pressure nozzles will not draw detergent from the tank. The solution should be sprayed in an upward motion to prevent streaking, with each pass overlapping slightly to ensure full coverage. 

Once the detergent is applied, it should be allowed to dwell for 5–10 minutes to loosen dirt and stains. However, it should not be allowed to dry. On hot, sunny, or windy days, the detergent may need to be reapplied after a few minutes to ensure it remains wet on the surface. 

Once the soap has loosened the grime, the detergent tank valve should be switched to "Off" and the sprayer nozzle trigger squeezed to flush the remaining detergent out of the line. The nozzle should then be changed to a higher-pressure tip appropriate for the surface being cleaned. 

The surface should be rinsed from top to bottom to ensure it is fully clean. Finally, the surrounding area and foliage should be sprayed with water to rinse away soap and further dilute any remaining detergent to protect plants. 

Sanitizers, Disinfectants, and Other Chemicals 

When standard soap or detergent is insufficient, chemical injectors and powerful sanitizing solutions may be required. These solutions are designed to kill bacteria and other organisms. 

Sanitizers and disinfectants often use stronger ingredients like citric acid, bleach mixtures (such as sodium hypochlorite), and ammonia. These chemical mixes frequently require specialized equipment to avoid damage and corrosion. Because these mixtures can be harmful to animals, people, and plants, they should be used with extreme care.