Field Rig Sizing Reference

Pressure Washer Nozzle Size Chart

Every spray tip has an internal orifice size that dictates how hard your pump works. If your nozzle is too small, your unloader valve spikes and cooks the pump seals. Too large, and your pressure drops through the floor. Use this chart to match your machine's real GPM and PSI, decode 5-digit tip stamps, or size nozzles for a rotary surface cleaner. (Need metric unit conversions? Use our PSI to BAR Converter).

Nozzle Orifice Size	Operating Pressure (PSI / BAR Equivalent) — Delivered Flow in GPM
Nozzle Orifice Size	1,000 PSI (70 BAR)	1,500 PSI (100 BAR)	2,000 PSI (140 BAR)	2,500 PSI (170 BAR)	3,000 PSI (205 BAR)	3,500 PSI (240 BAR)	4,000 PSI (275 BAR)	4,500 PSI (310 BAR)	5,000 PSI (345 BAR)
# 2.0	1.00 GPM	1.22 GPM	1.41 GPM	1.58 GPM	1.73 GPM	1.87 GPM	2.00 GPM	2.12 GPM	2.24 GPM
# 2.5	1.25 GPM	1.53 GPM	1.77 GPM	1.98 GPM	2.17 GPM	2.34 GPM	2.50 GPM	2.65 GPM	2.80 GPM
# 3.0	1.50 GPM	1.84 GPM	2.12 GPM	2.37 GPM	2.60 GPM	2.81 GPM	3.00 GPM	3.18 GPM	3.35 GPM
# 3.5	1.75 GPM	2.14 GPM	2.47 GPM	2.77 GPM	3.03 GPM	3.27 GPM	3.50 GPM	3.71 GPM	3.91 GPM
# 4.0	2.00 GPM	2.45 GPM	2.83 GPM	3.16 GPM	3.46 GPM	3.74 GPM	4.00 GPM	4.24 GPM	4.47 GPM
# 4.5	2.25 GPM	2.76 GPM	3.18 GPM	3.56 GPM	3.90 GPM	4.21 GPM	4.50 GPM	4.77 GPM	5.03 GPM
# 5.0	2.50 GPM	3.06 GPM	3.54 GPM	3.95 GPM	4.33 GPM	4.68 GPM	5.00 GPM	5.30 GPM	5.59 GPM
# 5.5	2.75 GPM	3.37 GPM	3.89 GPM	4.35 GPM	4.76 GPM	5.14 GPM	5.50 GPM	5.83 GPM	6.15 GPM
# 6.0	3.00 GPM	3.67 GPM	4.24 GPM	4.74 GPM	5.20 GPM	5.61 GPM	6.00 GPM	6.36 GPM	6.71 GPM
# 6.5	3.25 GPM	3.98 GPM	4.60 GPM	5.14 GPM	5.63 GPM	6.08 GPM	6.50 GPM	6.89 GPM	7.27 GPM
# 7.0	3.50 GPM	4.29 GPM	4.95 GPM	5.53 GPM	6.06 GPM	6.55 GPM	7.00 GPM	7.42 GPM	7.83 GPM
# 8.0	4.00 GPM	4.90 GPM	5.66 GPM	6.32 GPM	6.93 GPM	7.48 GPM	8.00 GPM	8.49 GPM	8.94 GPM
# 9.0	4.50 GPM	5.51 GPM	6.36 GPM	7.12 GPM	7.79 GPM	8.42 GPM	9.00 GPM	9.55 GPM	10.06 GPM
# 10.0	5.00 GPM	6.12 GPM	7.07 GPM	7.91 GPM	8.66 GPM	9.35 GPM	10.00 GPM	10.61 GPM	11.18 GPM
# 12.0	6.00 GPM	7.35 GPM	8.49 GPM	9.49 GPM	10.39 GPM	11.22 GPM	12.00 GPM	12.73 GPM	13.42 GPM

Machine Category	Typical Specs	Target Pressure	Required Orifice #	Standard Tip Codes (25° / 40°)	Engineering Note
Electric Detailing	2.0 GPM @ 1,000 PSI	1,000 PSI	# 4.0	`25040` / `40040`	Keeps pressure around 1,000 PSI while pulling high water flow to lubricate paint without clearcoat scratches.
Electric Residential	1.2 GPM @ 1,700 PSI	1,700 PSI	# 2.0	`25020` / `40020`	Matched for small 13-amp universal motors without tripping household 15A breakers.
Homeowner Gas	2.5 GPM @ 3,000 PSI	3,000 PSI	# 3.0	`25030` / `40030`	The sweet spot for driveway concrete and fence prep without gouging soft wood.
Mid-Duty Gas	3.0 GPM @ 3,000 PSI	3,000 PSI	# 3.5	`25035` / `40035`	Direct-drive pump standard. Easily spins a 12" to 14" surface cleaner.
Pro Direct Drive	3.5 GPM @ 4,000 PSI	4,000 PSI	# 3.5	`25035` / `40035`	Delivers true 4,000 PSI blast. Step up to a #4.5 tip if washing wood to avoid tearing the grain.
Commercial Workhorse	4.0 GPM @ 3,500 PSI	3,500 PSI	# 4.5	`25045` / `40045`	The daily contractor staple. Feeds a 16" to 20" surface cleaner with dual #2.5 tips.
High-PSI Commercial	4.0 GPM @ 4,000 PSI	4,000 PSI	# 4.0	`25040` / `40040`	At 4,000 PSI, GPM directly equals orifice size (#4.0 orifice = exactly 4.0 GPM).
Commercial Soft-Wash	5.5 GPM @ 3,000 PSI	3,000 PSI	# 6.5	`25065` / `40065`	High-volume rinse rig for fast two-story siding flushes and commercial flatwork.
Dual-Gun / Heavy Rig	8.0 GPM @ 3,000 PSI	3,000 PSI	# 9.5 / # 10.0	`25100` / `40100`	Splits 8 GPM cleanly across two operators running wands with #4.5 or #5.0 nozzles each.

5 Standard Quick-Connect Spray Tip Degrees

Color coding indicates the fan spray angle only. The numerical orifice stamped on the tip dictates your pump pressure.

0° Red Blast

Pinpoint Jet

A solid, laser-tight water jet with zero fan spread. It hits with pure mechanical impact. Good for chipping dried mortar or peeling rust off heavy iron.

Use On: Heavy iron rust, caked excavator mud. Never use on wood, siding, glass, or vehicles.

15° Yellow Chisel

Stripping Fan

Acts like a high-pressure putty knife. The narrow chisel lifts peeling paint from masonry, strips old deck stain, and breaks up packed road grime.

Use On: Paint prep, stripping deck stain, baked-in oil grime on concrete.

25° Green Clean

Universal Wash

The tip you will reach for 80% of the time. Wide enough to sweep concrete quickly, but tight enough to scour away green mold and black mildew.

Use On: Driveways, sidewalks, brick pavers, composite decks, vinyl siding.

40° White Wash

Gentle Fan

Spreads water into a broad, soft curtain. Built for jobs where concentrated pressure does damage—rinsing vehicles and washing siding without blasting weep holes.

Use On: Car detailing, fragile window screens, soft wood furniture, stucco.

65° Black Soap

Low-PSI Chemical

Has a wide brass bore that drops line pressure under 200 PSI. That drop creates the vacuum inside your downstream injector, pulling soap right out of your jug.

Use On: Siphoning house wash detergent, foaming lances, garden soaking.

How to Read Nozzle Tip Codes

Pick up any quick-connect nozzle and look at the hex flat. You will see a stamped 5-digit number like 25040. Those numbers are not random part IDs—they tell you the exact fan pattern and hole diameter:

First Two Digits (25): Spray angle in degrees. 25 means a 25° Green fan pattern.
Last Three Digits (040): Orifice size rating with an implied decimal. 040 means a #4.0 orifice.

Common Rig Tip Examples:
• 40030 = 40° White tip, #3.0 orifice
• 15045 = 15° Yellow tip, #4.5 orifice
• 00025 = 0° Red pinpoint jet, #2.5 orifice

Surface Cleaner Multi-Nozzle Rule

A common rookie mistake is screwing two stock wand tips into a rotary surface cleaner. Surface cleaners divide your machine's total water flow across all spinning nozzles on the bar:

Orifice Size Per Tip = (Machine GPM ÷ Number of Tips) × √(4000 ÷ Operating PSI)

Real-world example: If you run a 4.0 GPM @ 3,500 PSI machine on a 2-nozzle spray bar, each nozzle only receives 2.0 GPM. Sizing at 3,500 PSI gives ~#2.14 per tip. You must install two #2.0 or #2.5 nozzles. If you screw in two stock #4.0 nozzles, your machine tries to feed an #8.0 opening—your pressure collapses from 3,500 PSI down to roughly 875 PSI.

Engineered & Field-Tested by Najam | Mechanical Engineer & Founder

Najam is a mechanical engineer who tests pump hydraulics, nozzle wear, and unloader valve tolerances. Every formula and flow benchmark in this chart is derived directly from fluid orifice physics and factory calibration data. Read more about our engineering methodology.