Pressure washing equipment
Two numbers describe a pressure washer: PSI (force) and flow rate. Both matter, and so does the nozzle. NPS guidance on masonry notes that nozzle distance and gallons per minute are important variables alongside pressure. For exterior house work, the more relevant question is whether the contractor also carries a soft wash setup - a low-pressure applicator for cleaning solutions - because that is the correct tool for roofs, wood and most siding.
PSI is not a quality rating. A higher-PSI machine is not a better machine for house work; it is a more dangerous one in the wrong hands. What matters is whether it can be dialed down and whether the operator does. Fixr's material-by-material PSI guidance spans roughly 500 PSI for brick and softwoods up to 3,500 for concrete - one machine, many settings.
Nozzles. The tip changes the spray from a narrow, concentrated jet to a wide fan. A wide-angle tip at distance is gentle; a narrow tip up close will carve wood and etch stone at the same machine setting. Today's Homeowner's cedar guidance calls for a wide-angle nozzle roughly two feet away at a 45-degree angle.
Hot vs cold. Heated machines help with grease and oil. Fixr prices heated power washing on fences slightly above cold pressure washing - $0.35 to $0.45 versus $0.30 to $0.40 per square foot - and notes heat can cause minor damage to older wooden fences. NPS describes steam cleaning as low-pressure hot water washing, illustrating it at under 100 psi, and calls it gentle and effective for stone, particularly acid-sensitive stone.
Soft wash systems. These apply diluted cleaning solution at low pressure and are the right tool for roofs, siding and wood. A contractor whose entire kit is a high-pressure machine can only do one thing, and that thing is wrong for most of your house.
Water supply. Machines need continuous water. Ask where they're drawing from and whether they bring a tank. It matters if you're on a well or have low pressure - running a pump dry is the contractor's problem, but a mid-job stoppage becomes yours.
Choosing pressure washing equipment
The judgement calls that decide the bill, before anyone quotes you.
- Ask to see the soft wash setup If the answer is 'we just turn the pressure down,' they don't have one. A low-pressure applicator for solution is a different piece of equipment.
- Ask which nozzle goes on which surface Someone who can answer this has been trained. Someone who talks only about machine PSI has not.
- Don't pay extra for hot water by default It earns its upcharge on grease and oil. On general dirt and algae it adds cost and, on older wood, some risk.
- Confirm the water source Ask whether they're using your supply or bringing a tank, especially if you're on a well or your pressure is low.
- Don't buy a machine to solve a judgment problem Consumer pressure washers are more than powerful enough to wreck siding. The skill is in restraint, not in horsepower.
All pressure washing equipment
Pressure Washers PSI Classes
Soft Wash Systems
Surface Cleaners
Extension Wands
Chemical Injectors
Hot Water Pressure Washers
Downstream Injectors
Nozzle Types
Where these figures come from
Sources last checked
- Fixr - Cost to Pressure Wash a Fence (PSI by material, hot vs cold pricing) · retrieved 2026-07-26
- Fixr - Cost to Pressure Wash a House (PSI range) · retrieved 2026-07-26
- Fixr - Cost to Pressure Wash a Deck (PSI guidance) · retrieved 2026-07-26
- Today's Homeowner - Pressure Washing Cedar Siding · retrieved 2026-07-26
- NPS Preservation Brief 1 - Cleaning and Water-Repellent Treatments for Historic Masonry (PDF) · retrieved 2026-07-26
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