Greene County
Pressure Washing

Brick

Brick walls, chimneys and steps can be washed with water pressure, within limits. Too much pressure eats the mortar and the face of the brick, and that damage is permanent.

Low pressure, wide tip

Method
Saturate first, apply cleaner gently, rinse at low pressure.
Pressure
Rinse at 400 psi or less, 25 to 50 degree fan tip, at least 12 inches away1.
Cleaners
Only cleaners suited to your brick. No unbuffered muriatic acid.

Pressure or soft washing

Soft wash Cleaner goes on first, a soft brush does the scrubbing, and a garden hose does the rinsing.
distance
Pressure wash A machine pushes water through a nozzle. The tip, the distance and the angle set how hard it hits. Low pressure, wide tip

The Brick Industry Association says to consult the brick manufacturer before using pressurized water on brick at all. It warns that excessive pressure can damage brick surfaces, erode mortar joints and remove finishes or coatings, leaving a different appearance1.

Its method is wet, then clean, then rinse. Saturate the area with water first so the brick doesn’t soak up the cleaner, apply the cleaning solution gently, and rinse thoroughly1.

Nozzle and pressure

40° 25° 15° 0°
Spray angle by nozzle tip. A narrow angle puts the same water on one small spot; a wide fan spreads it out. Named in this guide: 25°, 40°.

BIA sorts water pressure into classes: very low is under 100 psi, low is 100 to 400 psi, and medium is 400 to 800 psi, to be used only if the brick manufacturer permits it1. Above 800 psi, it says high-pressure water cleaning is not appropriate for brick and may damage it1.

Unless the brick maker allows more, keep to 400 psi or less measured at the nozzle tip1. Use a 25 to 50 degree fan-shaped nozzle and keep the tip at least 12 inches from the brick1.

For prewetting, BIA recommends very low pressure, no more than 100 psi1. Cleaning solution should go on at no more than 50 psi, because higher pressure pushes it deep into the masonry where it can become a source of future staining1.

Cleaners to use and avoid

Use

  • Plenty of plain water to saturate the wall before any cleaner goes on1.
  • A cleaning solution your brick maker approves, applied at low pressure1.

Avoid

  • Unbuffered muriatic (hydrochloric) or hydrofluoric acid, which tend to cause more stains and damage mortar joints1.
  • High-pressure water, which cleans by abrasion and can etch mortar joints and strip the outer surface of the brick1.

Protect plants and keep runoff out of drains

Cleaning chemicals can damage plants and grass. The Brick Industry Association’s advice holds for any surface: protect nearby plants, and where needed keep the cleaning solution and runoff off plants and the soil around them1. Soaking beds with plain water before and after, and covering what you can, is the practical version of that.

Street drains are not sewers. EPA reminds people that storm drains lead directly to local waterways, not to treatment facilities. Its tips for washing outdoors: use biodegradable, phosphate-free, water-based detergents, use as little as you can, wash on a driveway or yard rather than in the street, and send the wash water onto grass or gravel2. In Greene County, polluted runoff that enters the storm sewers is often discharged into local rivers and streams without treatment3, and Beavercreek asks residents not to dump anything down a storm sewer or drain4.

If you see suds, a rainbow sheen or an odd color in a ditch, stream or storm drain, Greene County asks you to report it to the County Engineer’s Office at 937-562-75005.

Common damage

  • Stripped mortarHigh-pressure water can etch and erode mortar joints1.
  • A damaged brick faceThe same abrasion can remove the outer surface of the brick, which BIA describes as permanent damage1.
  • New stainsCleaner forced in under pressure can come back later as staining1.

When not to pressure wash at all

  • Above 800 psi, which BIA calls inappropriate for brick1.
  • Above 400 psi unless the brick manufacturer permits it1.
  • Where mortar joints are already soft or crumbling. Eroded joints are exactly the damage BIA warns about, so more water pressure is the wrong tool there1.

Step by step

  1. Check with the makerLook up whether your brick manufacturer allows pressurized water, and at what pressure.
  2. Protect plants and drainsSoak and cover nearby plants. Plan where the rinse water will run.
  3. Saturate the wallWet the area thoroughly with plain water at very low pressure, no more than 100 psi1.
  4. Apply the cleaner gentlyPut the cleaning solution on at no more than 50 psi and let it work as its label says1.
  5. Rinse with a fan tipRinse with a 25 to 50 degree fan tip held at least 12 inches away, at 400 psi or less unless the brick maker allows more1.

Before you start, read the safety page. If the job looks bigger than you want to take on, DIY or hire lays out what each way involves.

Sources

Every superscript number on this page points to one of these. Each was read on the date shown.

  1. Technical Note 20: Cleaning Brickwork (August 2018) Brick Industry Association. Checked 2026-10-26.
  2. Stormwater Best Management Practice: Vehicle Maintenance and Washing (EPA-832-F-21-032F) U.S. Environmental Protection Agency. Checked 2026-10-26.
  3. Stormwater Basics Greene County, Ohio. Checked 2026-10-26.
  4. FAQs: Stormwater Program City of Beavercreek, Ohio. Checked 2026-10-26.
  5. Illicit Discharge & Illegal Dumping Greene County, Ohio. Checked 2026-10-26.