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The Dangers of Etching: How the Wrong Pressure Scars Concrete, Wood and Brick

Etching is what happens when a pressure washer stops removing dirt and starts removing the surface. It can scar a driveway, deck or brick wall, and it can't be washed out.

Updated October 19, 2026 · About 7 min read · By ACE – Advanced Cleaning Experts

The short version

  • Etching means material is gone. The stream cut away part of the surface itself, not just the dirt on it.
  • Four things cause it: too much pressure, too narrow a tip, too little distance and lingering in one spot.
  • It's permanent. Cleaning can't put back concrete, wood fiber or brick face that has been blasted off.

What etching actually is

Dirt, mildew and grime sit on a surface. A good clean takes that layer off and stops. Etching goes one step further and removes part of the material underneath. Consumer Reports warns that a pressure washer's stream can damage paint, nick or etch wood and even etch certain types of stone (Consumer Reports). The trade group for concrete masonry says high-pressure equipment can be very effective, but improperly applied it can cause severe damage (CMHA).

Cleaning removes dirt. Etching removes the surface. Two cross-sections of the same surface. Left: a proper clean takes off the dirt layer and leaves the surface intact. Right: too much pressure, too close, cuts into the surface itself, leaving a groove that stays after the dirt is gone. Cleaning Etching dirt left dirt removed surface layer intact surface layer cut away narrow tip, too close wide fan, proper distance
Simplified diagram. Dirt sits on top of the surface. Etching takes away part of the surface itself, which is why it doesn't wash out.

The four things that decide it

Etching is rarely about one setting. It comes from a combination:

  • Pressure. Each surface has a ceiling. Concrete Network advises keeping concrete under 3,000 PSI to avoid etching or surface damage (Concrete Network).
  • Tip angle. The lower the number, the narrower and harder the stream (Consumer Reports). A 0-degree tip concentrates everything onto a pinpoint.
  • Distance. Brick guidance calls for a minimum of 12 inches between nozzle and brick (BIA), and James Hardie asks for at least 6 feet on its siding (James Hardie).
  • Time in one spot. A stream that stops moving keeps cutting in the same place.
The four things that decide whether a stream etches Pressure, tip angle, distance and how long the stream stays in one spot. A narrow tip, held close, at high pressure, lingering in one place, is the most likely to etch. PressureTip angleDistanceTime in one spot safer: lowersafer: wider fansafer: farthersafer: keep moving risk: higherrisk: 0° or 15°risk: inches awayrisk: lingering Gentle: cleans the dirt layer Aggressive: cuts the surface They stack. A safe pressure can still etch through a narrow tip held close, and a wide tip can still mark if it lingers.
Simplified diagram. Manufacturers' limits combine these factors; see does PSI really matter?

Concrete: wand marks, lines and a rough surface

Concrete is tough, but its top surface is the smoothest, most finished part of the slab. In our experience, when a narrow tip is swept across it too close, the stream can cut into that top layer and leave marks that follow the path of the wand: typically arcs, lines or a rougher, sandier patch where the stream lingered. Because the texture has changed, those marks usually stay visible after the concrete dries and even after the next cleaning.

The professional association Power Washers of North America teaches flatwork cleaning specifically so contractors can restore hard surfaces without causing etching or other surface damage (PWNA). The usual tool for even pressure on flatwork is a rotary surface cleaner, which keeps its nozzles at a fixed distance for a balanced pattern (Mi-T-M). We cover that in surface cleaner vs wand.

New concrete is more vulnerable. Concrete typically takes about 28 days to fully cure (Concrete Network), so ask your installer before anyone pressure washes a new slab.

Wood: torn fibers and a fuzzy surface

Wood is much softer than concrete. Its surface is made of fibers, and a strong stream can tear them loose. Consumer Reports notes that pressure-treated pine decking is generally fine if the nozzle isn't held too close, and it suggests starting with a low-pressure nozzle in a hidden spot, working with the grain, at about 800 to 1,000 PSI for decks (Consumer Reports).

In our experience, etched wood typically shows up as raised, fuzzy fibers, light-colored stripes that follow the wand, or soft grain that has been dug out between the harder growth rings. Once the fibers are torn, rinsing can't reattach them; the board may need sanding, or replacement if the damage is deep. More in wood fence: weathering vs mildew.

Brick: eroded mortar and a lost face

Brick looks indestructible, but the Brick Industry Association is direct about it. It says excessive pressure may damage brick surfaces, erode mortar joints and remove finishes or coatings, changing the wall's appearance. It classifies anything over 800 PSI as not appropriate for brick, allows 400 to 800 PSI only when the brick manufacturer permits, and recommends low pressure, under 400 PSI, for rinsing. It also says abrasive and high-pressure methods that remove stains by abrasion can etch mortar joints and remove the outer surface of brick, resulting in permanent damage (BIA).

Mortar is meant to be the softer part of a brick wall. National Park Service guidance on repointing says mortar should be softer than the bricks themselves, so it serves as the sacrificial part of the wall (National Park Service). In our experience, that's why the joints usually show damage first: they look recessed, sandy or uneven. A damaged brick face typically looks rougher or a different color than the bricks around it.

Why etching is permanent

Stains can be treated and dirt can be rinsed, because both are something added to the surface. Etching is something taken away. There's nothing left to clean back to; the original finish, fiber or mortar is gone. Repairs mean resurfacing concrete, sanding or replacing wood, or repointing mortar joints, all of which cost far more than doing the cleaning gently in the first place.

Safety note: The same stream that etches concrete can injure skin. Consumer Reports recommends never using the red 0-degree nozzle, because it can pierce surfaces, including protective boots (Consumer Reports).

How ACE avoids it

We match the method to the surface. Flat concrete gets our 3,000 PSI, 5.5 GPM pressure washer with a 20-inch surface cleaner, which keeps the spray at an even height, and siding, brick and shingle roofs get a soft wash: a cleaning solution at low pressure and a gentle rinse. If you're not sure what your siding is, or your concrete is new, tell us when you ask for a quote.

Quick answers

What is etching from pressure washing?

Etching is damage where the stream removes part of the surface itself, not just the dirt on it. Typically, it shows up as wand marks or lines on concrete, fuzzy or gouged wood and eroded mortar or a roughened face on brick.

What causes etching?

A combination of too much pressure, too narrow a tip, too little distance and letting the stream linger in one spot. Each surface has its own limits, so a setting that's fine on concrete can etch wood or brick.

Can etched concrete be fixed by cleaning it again?

No. Etching means material has been removed, so there's nothing for cleaning to restore. Repairs usually mean resurfacing. Uneven cleaning can look similar, so it's worth having someone look before assuming the worst.

What pressure is too much for brick?

The Brick Industry Association classifies anything over 800 PSI as not appropriate for brick, allows 400 to 800 PSI only if the brick manufacturer permits it and recommends under 400 PSI for rinsing, using a 25- to 50-degree fan tip at least 12 inches away.

How do I avoid etching my driveway?

Stay within the surface's limits, use a wide tip, keep a steady distance and keep moving. A rotary surface cleaner helps on flat concrete because it holds the nozzles at a fixed height for an even pattern. Ask your installer before washing new concrete, which typically takes about 28 days to cure.

Sources

  1. Can You Pressure-Wash It?, Consumer Reports. https://www.consumerreports.org/home-garden/pressure-washers/surfaces-safe-to-clean-with-a-pressure-washer-a5445180933/
  2. New Concrete? Common Care Questions Answered, Concrete Network. https://www.concretenetwork.com/concrete/new-faqs.html
  3. Removal of Stains From Concrete Masonry (TEK 08-02A), Concrete Masonry & Hardscapes Association. https://www.cmha.org/resource/tek-08-02a/
  4. Flatwork Certification, Power Washers of North America (PWNA). https://www.pwna.org/certificate-courses/flatwork-certification
  5. Technical Note 20: Cleaning Brickwork, Brick Industry Association. https://www.gobrick.com/media/file/20-cleaning-brickwork.pdf
  6. Preservation Brief 2: Repointing Mortar Joints in Historic Masonry Buildings, U.S. National Park Service. https://www.nps.gov/orgs/1739/upload/preservation-brief-02-repointing.pdf
  7. Pressure Washer FAQ: PSI vs GPM, hot vs cold water, rotary surface cleaners, Mi-T-M Corporation. https://www.mitm.com/consumer/pressure-washers/
  8. Siding Cleaning and Maintenance (Technical Bulletin), James Hardie. https://assets.ctfassets.net/dzi2asncd44t/1mcW7pxuTmKq1nWLOgTRbW/40f30c33fe5a8f9b9ea5ffdbffae86ae/20-james-hardie-siding-cleaning-and-maintenance.pdf

Links checked October 19, 2026. This page is general information, not a substitute for your manufacturer's instructions or a product label.