Understanding Pressure Washer Nozzles: What Those Numbers and Colors Really Mean

When you’re using a pressure washer, the nozzle might look like a simple piece of hardware — but it’s actually one of the most important parts of the entire setup. The nozzle determines how your washer performs, how much pressure you get, and how wide the spray pattern will be.

In this post, we’ll break down the three key specs that define every pressure washer nozzle and explain how to read the numbers (and colors) printed on them.

1. Plug Diameter

The plug diameter is the size of the fitting that connects the nozzle to your spray wand or gun.

The standard plug diameter is ¼ inch, which fits most consumer and professional pressure washers.

Make sure your nozzle’s plug diameter matches your wand — even a small mismatch can cause leaks or prevent the nozzle from locking in properly.

2. Fan Angle

The fan angle tells you how wide the spray of water will be when it leaves the nozzle. A narrower fan angle produces a tighter, more concentrated stream — which means higher effective pressure on the surface. A wider fan angle spreads the water out more, making it gentler and better for covering large areas.

Fan angle is measured in degrees, and it’s often represented by a color code:

🔴 Red - 0° - Pinpoint stream for tough stains and deep cleaning (use with caution)

🟡 Yellow - 15° - Medium-intensity cleaning for driveways, patios, and siding

🟢 Green - 25° - General-purpose cleaning for vehicles, outdoor furniture, and decks

⚪ White - 40° - Gentle rinsing for delicate surfaces like windows and painted finishes

3. Nozzle Size (Orifice Size)

The nozzle size determines how much water can flow through the nozzle. It’s measured using an industry rating system that refers to the flow rate at 4000 PSI (pounds per square inch).

For example, a 3.5 nozzle size allows 3.5 gallons per minute (GPM) at 4000 PSI.

Choosing the right nozzle size ensures your pressure washer maintains proper pressure and water flow — too small, and you’ll restrict the flow; too large, and you’ll lose cleaning power.

How to Read the Numbers on a Nozzle

Most pressure washer nozzles have a number stamped on the plug, typically in the format “##0##.”

Here’s how to decode it:

• • • The first two digits represent the fan angle.

    • The last two digits represent the nozzle (orifice) size.

For example: a nozzle labeled 15037 has a 15° fan angle and a 3.7 nozzle size.

Choosing the Right Nozzle for the Job

If you’re tackling tough grime on concrete, go with a lower-angle nozzle (like 0° or 15°). For washing cars, boats, or outdoor furniture, use a wider fan angle (25° or 40°) to prevent surface damage.

And remember — always start with a wider angle and work your way down to find the right balance of cleaning power and safety.