A pressure washer’s size or power is measured in pounds per square inch (PSI). The amount of pressure you need will depend on your project and the material you’re washing, but consumer pressure washers range from 500 to 2,400 PSI. Porous materials like brick and stucco should not be blasted with anything stronger than 1,000 PSI, while you can use a PSI of up to 2,400 to clean a vinyl fence.

When hiring a professional to pressure wash your home, it's crucial to choose a company that is bonded, licensed, and insured. This protects you from liability if any accidents or property damage occur during the service; otherwise, the cost could fall on you. Before making a decision, vet at least three different contractors. Conduct thorough research by reading customer reviews, looking at examples of their previous work, and verifying the company's license. Before signing a contract, ensure you receive a written estimate that details all project costs. It's also wise to ask potential contractors a series of questions to gauge their professionalism and experience, such as:

• How many years of experience do you have?

• What are your credentials?

• What cleaning methods do you use?

• Do you have a workmanship warranty and insurance?

• What is your availability?

• What is your policy if you damage my property?

• How long will the job take to complete?

• How much do you charge?

• What is your cancellation policy?

• Do you offer a customer satisfaction guarantee or any additional services?

No, pressure washing isn’t recommended for cartridge filters. The high pressure can damage the filter paper, and the gentler pressure from a regular garden hose will work to rinse the cartridge filter. If the cartridge is very dirty or has algae or mineral buildup, you can use a muriatic acid solution to soak the filter and remove the buildup.

One of the most important factors to consider when buying a pressure washer is not just psi but also the machine’s overall cleaning power. This is based on both the psi and the GPM. Look for a cleaning rating, or effective cleaning unit (ECU), of up to 8,000 for most residential cleaning projects that require a pressure washer.