Questions to ask a pressure washing company before you hire

Updated · KeystoneProGuide editorial team

What should you ask a pressure washing company before hiring it?

Ask questions that a good company can answer specifically and a poor one cannot: its registration number, whether it is lead-safe certified, what pressure and which products it will use on each of your surfaces, and where the water will go. The list below groups the questions by topic, with the reason for each. Put them to every company you are considering, and compare the answers as closely as you compare the prices.

About the business

  • "What is your Pennsylvania home improvement registration number?" Registered firms must show it as PA followed by digits, and you can check it in the Attorney General's contractor search, which lists "Pressure Washing" among its work types.
  • "What insurance do you carry, and can I see proof?" Registered contractors must carry at least $50,000 of personal injury cover and $50,000 of property damage cover, according to the Attorney General's questions and answers.

About an older house

  • "Do you know when my house was built, and does it matter to you?" If the answer is before 1978 and the job touches paint, it should matter. The U.S. Environmental Protection Agency (EPA) requires anyone paid to disturb painted surfaces on such a home to be lead-safe certified.
  • "Is your firm lead-safe certified, and how will you contain the work?" The EPA's archived answer on washing says the firm must stop dust and debris, including what is carried in the waste water, from leaving the work area.

About the method for each surface

  • "What pressure will you use on my siding, and does my siding's maker allow it?" The vinyl siding industry's association, PEPA, says some makers do not recommend power washing at all and others limit the pressure and cleaners that can be used.
  • "How will you clean my roof?" If the answer involves a pressure washer on asphalt shingles, the shingle makers' trade association, ARMA, says that is likely to damage the roof. Its own method is a gentle bleach solution, left 15 to 20 minutes and rinsed gently.
  • "What will you do differently on the brick?" The National Park Service recommends 100-400 psi for historic masonry, with the wand at least 12 inches away, and warns that many machines run far higher.
  • "Will you rely on the cleaner or on pressure for the deck?" A Forest Products Laboratory chemist advised letting the cleaner do the work, because a power sprayer can damage the wood surface.
  • "Where will you do a test patch?" Both the Park Service and PEPA say to test on a small, hidden area before cleaning the whole surface.

About chemicals

  • "Which products will you use, and may I see the labels?" A product whose label claims to kill or remove a pest, including algae, mold or mildew, is likely a pesticide in the EPA's terms, and the EPA says such products must be registered before they can be legally sold.
  • "Do you hold a Pennsylvania pesticide applicator license?" The state Department of Agriculture requires one to use pesticides on another person's property. Its page does not say how that applies to house-washing products, so ask the company how it reads the rule.
  • "How will you protect my plants, and do you ever mix bleach with other cleaners?" ARMA asks for care with the landscape, and the EPA says never to mix chlorine bleach with cleaners that contain ammonia, since toxic fumes could be produced.

About the water

  • "Where will the wash water go?" The Philadelphia Water Department says only rain should go in storm drains, and the EPA tells firms washing old painted surfaces to dispose of waste water properly. A company should have an answer for your property, not a general reassurance.
  • "Will you use my water?" Fixr's cost survey says you may pay about $2 an hour for water a crew draws from your tap.

About the price

  • "How is the price worked out?" By the square foot, by the hour or by the surface. HomeAdvisor gives $0.10 to $0.50 a square foot, about $50 to $100 an hour per crew member, and a typical minimum of about $100.
  • "Is there a minimum charge, and what is not included?" Fixr says minimums of $100 to $350 are common. Ask whether sealing, staining, gutters or extra rinsing are extra.

About the contract

  • "Will you put the scope, dates and total price in writing?" For a home improvement over $500, Pennsylvania law requires a written, signed contract with those terms and a notice of your right to cancel. The Attorney General reported in May 2026 that you can cancel within three business days of signing by any means, provided the contractor receives notice.
  • "What happens if something is damaged?" Ask how a claim would be handled and against which policy.

What happens on the day shows what good practice looks like once work starts, and how to choose a company covers the checks to make before you call. Businesses offering the service are on the pressure washing directory page.

Sources

  1. Home Improvement Contractor Search, Pennsylvania Office of Attorney General
  2. Frequently Asked Questions: Home Improvement Contractor Registration, Pennsylvania Office of Attorney General
  3. Lead Renovation, Repair and Painting Program, U.S. Environmental Protection Agency
  4. How do RRP requirements apply to pressure washing? What containment and other preparation are required?, U.S. Environmental Protection Agency (January 2025 archived copy)
  5. How to Clean Vinyl Siding, Polymeric Exterior Products Association (PEPA)
  6. Algae Discoloration of Roofs, Asphalt Roofing Manufacturers Association (ARMA)
  7. Preservation Matters: Maintenance - Graffiti Removal from Historic Features, National Park Service
  8. Springtime Means Deck Maintenance for Many Homeowners, USDA Forest Service, Forest Products Laboratory (news release via Newswise)
  9. What is a Pesticide?, U.S. Environmental Protection Agency
  10. Pesticide Applicators, Registered Technicians, and Certification Exams, Pennsylvania Department of Agriculture
  11. A Brief Guide to Mold, Moisture and Your Home, U.S. Environmental Protection Agency
  12. Taking Care of Storm Drains, Philadelphia Water Department
  13. How Much Does Pressure Washing Cost? [2025 Data], HomeAdvisor
  14. How much does it cost to pressure wash the exterior of a house?, Fixr
  15. PA Supreme Court Upholds Consumer Right-to-Cancel Home Improvement Contracts Within Three Days Regardless of Medium, Pennsylvania Office of Attorney General

Find Pressure Washing businesses

Pressure Washing in Pennsylvania

More Pressure Washing guides

All Pressure Washing guides