Pressure washing seems straightforward until you get a quote that's half the price of another, or you hire someone who returns your patio looking worse than before. The difference between a professional contractor and a backyard operator often isn't obvious until money and property are at stake.
Here are the red flags that should stop you from signing a contract.
No Insurance or Bonding
Ask every contractor directly: "Are you insured and bonded?" Get their insurance certificate via email before work begins. Legitimate pressure washing companies carry general liability insurance ($1–2M coverage is standard) and sometimes bonding for customer protection.
If a contractor refuses to provide proof or says "cash only" to avoid paperwork, walk away. You're liable if someone gets hurt on your property or if damage occurs during the job, and their insurance should cover it—not yours.
Vague or Verbal-Only Estimates
A professional gives you a written estimate that specifies:
- What surfaces will be cleaned (deck, driveway, siding, roof)
- PSI levels they'll use (typically 1,500–4,000 PSI for decks, 3,000+ for concrete)
- Type of cleaning method (pressure wash vs. soft wash)
- Timeline and weather contingencies
- Total cost with any add-ons listed separately
If they ballpark it over the phone or text, you have no recourse if the final bill doubles. Compare quotes in writing—you should collect 2–3 estimates before deciding.
Pressure Washing Everything
A contractor who wants to pressure wash your vinyl siding, roof, or delicate wood surfaces at high PSI is signaling inexperience. Soft washing (low-pressure application of biodegradable cleaning agents) is the right approach for:
- Roof cleaning (prevents shingle damage)
- Vinyl or aluminum siding
- Wood decks and fencing
- Window frames and brick
If they insist high-pressure is the answer to everything, they're likely cutting corners. Professional contractors know when to adjust technique based on the surface.
Unwillingness to Discuss Chemicals Used
Ask what cleaning solutions and detergents they use. Reputable contractors will name brands, explain whether they're eco-friendly, and confirm they're safe for your landscaping. They should also specify if they'll rinse thoroughly to prevent chemical residue.
Red flag: "We just use standard stuff" or refusing to disclose. You have a right to know what's being applied to your home and yard.
No References or Online Presence
Check for:
- Google reviews (aim for 4+ stars with recent activity)
- Before-and-after photos on their website or social media
- At least 3 customer references they can provide
- Years in business (2+ years is reasonable; 5+ is better)
One or two reviews, no website, and vague answers about past jobs suggest they're new or hiding poor work quality. Mercoly makes it easy to compare trusted pressure and soft washing providers side-by-side with verified reviews in one place.
Lowest Price Bid by a Large Margin
If one quote is 30–50% cheaper than the others, question why. Undercutting usually means:
- Cutting cleaning time short
- Using cheaper, less effective chemicals
- Skipping necessary steps like surface sealing after cleaning
- No insurance (hiding labor costs)
A typical driveway cleaning runs $150–$400 depending on size and condition. A roof soft wash might be $400–$1,200. If someone's quoting $80 for your entire driveway, that's unrealistic.
No Contract or Cancellation Policy
Before work starts, you should have a signed agreement that covers:
- Exact scope of work
- Start date and estimated completion date
- Payment schedule (deposit amount, balance due)
- What happens if weather delays the job
- Warranty on the work (30–60 days is standard)
- Cancellation terms
Verbal handshakes are worthless. A real contractor protects both of you with documentation.
Poor Communication or Responsiveness
If they're hard to reach during the quoting phase, they'll be impossible to reach if something goes wrong during the job. Test their responsiveness: Do they answer emails within 24 hours? Return calls? Explain things clearly?
A contractor who rushes through your questions or seems annoyed by follow-ups isn't a fit.
Frequently Asked Questions
Q: What PSI level is safe for my wood deck? Most wood decks need soft washing or pressure below 1,500 PSI to avoid gouging. A contractor should test an inconspicuous area first.
Q: Should I get my roof professionally cleaned, or will a pressure washer damage it? High-pressure washing damages asphalt shingles; soft washing (around 500 PSI with biodegradable detergent) is the correct method and costs $400–$1,200 for an average home.
Q: How long should pressure washing results last? On properly sealed concrete or wood, results typically last 6–12 months depending on weather and foot traffic; sealed surfaces last longer.
Use these red flags to vet contractors, and you'll avoid overpaying or dealing with damaged property.