8 Reasons Why Your Foam Cannon Might Not be Working Properly

Struggling with thin, watery foam from your snow foam lance? Can’t get those thick suds you’ve seen everyone else get?

In this article I’ll take you through 8 reasons why your snow foam cannon might not be working properly and how to fix them.

Reasons Why a Foam Cannon Might Not Work Properly:

  • Dial is turned the wrong way
  • Incorrect snow foam dilution ratio
  • Low water pressure/ flow rate
  • Leaks in the pressure washer/ lance connection points
  • Pickup pipe not connected fully or clogged up
  • Blocked orifice or filter/ gauze
  • Wrong orifice size for pressure washer
  • Poor quality snow foam

I’ll go through each issue and the fix in the sections below. They are listed in order of likelihood and priority so I’d recommend working through the list step by step to diagnose the problem, even if the first couple seem obvious!

1. Turn the Dial to Maximum

Pretty much every snow foam cannon has a dial on the top to control how much snow foam is drawn up from the bottle and goes through the nozzle and hence, how thick and concentrated the foam is.

On most foam cannons:

  • Turning the dial clockwise = thicker foam
  • Turning the dial counter-clockwise = thinner foam

On some foam cannons, the dial may work oppositely to as described above, so I’d advise trying the max setting in both directions to ensure this is not the issue.

2. Ensure the Dilution Ratio is Correct

The dilution ratio of different snow foams can vary considerably, so don’t assume that just because it was 1:9 with the last brand you used, that it’s the same when you try a bottle of something new.

The dilution ratio should be clearly stated on the back of the bottle, but if you can’t see it then it is probably on the brand’s website. In most cases, it will be between 1:4 and 1:20.

Some brands just state the ratio, and others will specify how many mL of snow foam and water to add to the reservoir.

Here is a table showing the most popular dilution ratios and the amount to add in mL and oz. to your lance. Most lances are 1L, so I’ve done the calculations for that volume, but you may want to adjust if you only want to fill your lance partway or have a smaller lance.


Dilution RatioSnow Foam RequiredWater Required
1:3250 mL750 mL
1:4200 mL800 mL
1:5170 mL830 mL
1:9100 mL900 mL
1:1090 mL910 mL
1:1565 mL935 mL
1:2050 mL950 mL
1:2540 mL960 mL

Fluid Ounces

Dilution RatioSnow Foam RequiredWater Required
1:38.8 oz26.4 oz
1:47.0 oz28.2 oz
1:56.0 oz29.2 oz
1:93.5 oz31.7 oz
1:103.2 oz32.0 oz
1:152.3 oz32.9 oz
1:201.8 oz33.4 oz
1:251.4 oz33.8 oz

3. Check Your Water Pressure

Pressure washers require a certain amount of water to be able to run properly. If the pressure washer is not being fed with enough water, it will damage it overtime and cause the snow foam to be thin and watery in the short-term.

Here’s how to check your water pressure/ flow rate is high enough:

  • Check the maximum flow rate of your pressure washer online (usually this is between 7-10 litres/ minute or 1.5-2.2 gallons per minute)
  • Get an empty bucket (at least 10 litres/ 2.2 gallons)
  • Take the hose that you are connecting directly to your pressure washer and place it over/ inside the bucket
  • Turn the tap on and set a timer for 1 minute
  • Measure how much water was collected in the bucket
  • Check that the amount of water collected in the bucket exceeds the maximum flow rate of the pressure washer

If you notice that the water pressure is low, then try this test again but fill the bucket directly from the tap. This will allow you to identify if it’s the hose or the tap that’s causing the problem.

If it’s the hose then it’s likely that there’s a kink somewhere that’s causing the drop in water pressure. If it’s the water source (tap), then you’ll need to do some further investigation or use a different tap which has enough flow.

4. Check for Leaks in the Pressure Washer and Lance Connections

Leaks in the connections on your pressure washer and foam lance can also lead to thin and watery snow foam similarly to the reasons described above.

Turn the pressure washer on and check for leaks at the following points:

  1. Pressure washer inlet which connects to the garden hose
  2. Pressure washer outlet which connects to the high pressure hose
  3. Connection between the pressure washer trigger and high pressure hose
  4. Connection between the foam lance and pressure washer trigger
  5. Connection between the foam cannon and foam cannon adapter

If you find any leaks in these areas, tighten them up or use PTFE to create a tighter seal. Even if the leak seems relatively small, it will still cause the snow foam to have a thinner and more watery consistency, so it’s worth doing this step.

5. Check the Pickup Pipe is Connected Properly

All snow foam cannons have a pickup pipe which collects the snow foam solution. Take the head of your foam cannon and ensure the pickup pipe is fully pushed in. If there is a slight gap then this will lead to watery snow foam.

It’s also worth checking at this point that the pickup pipe isn’t clogged up. You should be able to see this easily, but if not then you can always make sure by removing it and running water through it to check there’s no restrictions.

Some foam cannons have a filter at the bottom of the pickup pipe which is more prone to clogging. It’s worth cleaning this at least annually using a soft brush and dish soap and then rinsing thoroughly.

6. Clean the Orifice and Filter

If you’ve tried all the steps above and are still having issues with your foam cannon producing poor quality or even no foam at all, then you’ll need to take it apart and check that it isn’t clogged.

The process for this does vary between foam cannons but the following steps are typically involved:

  • Push the pin that connects the nozzle in and then slide off the nozzle.
  • Remove the gauze.
  • Remove the orifice using a flat headed screw driver.
  • Remove the adapter which connects the foam cannon to the pressure washer trigger.
  • Check that you can see all the way through the cannon at this point. If you cannot, then this will also need cleaning.
  • Place the metal components that you removed into caustic soda solution and leave for 24 hours.
  • Rinse thoroughly and reassemble the foam cannon.

Check out this guide to dismantling and cleaning a foam cannon for the step-by-step process with images.

7. Ensure the Orifice Size is Appropriate

The foam cannon orifice sits inside the foam cannon and controls the amount of water that passes through the foam cannon.

There are three standard snow foam orifice sizes:

  • 1.1 mm
  • 1.25 mm
  • 1.35 mm

The smaller the orifice, the more the flow will be restricted which results in thicker snow foam.

It’s important to use the correct size orifice for your pressure washer though:

  • Using an orifice which is too large will result in thin snow foam
  • Using an orifice which is too small will damage the pressure washer and can cause it to pulsate

The consequences of using an orifice which is too small are much greater compared to using one which is too large, so I personally err on the side of caution and size-up if I’m unsure.

The recommended orifice size depends on the flow rate and pressure rating of your machine. Here’s a rough guide:

Orifice SizePressure Washer SuitabilityExample Pressure Washer
1.10 mm90-110 barKarcher K2
1.25 mm110-150 barKarcher K4
1.35 mm150+ barKarcher K7

Most foam cannons come with a 1.25 mm orifice as standard. If you are unsure what size orifice your foam cannon has, then you can either Google it, or contact the manufacturer directly to confirm.

As you can see from the table, if you’re using a Karcher K2 and your foam cannon has a stock 1.25 mm orifice, then you can swap it out for a 1.1 mm orifice to get thicker foam.

You shouldn’t size-down though if you’re already using the correct size orifice as this can damage the pressure washer irreversibly.

Here’s a link to a 1.1 mm orifice on Amazon.

You can use the video in the section above to help you change the orifice.

8. Use a Different Snow Foam

If you’ve tried everything on this list and you’re still not getting good quality snow foam, then the chances are that you’re just using one that isn’t very good.

If you’re looking for some high quality car detailing products, check out my recommended products page for all my top picks.

It’s important to note though that thicker foam isn’t always better.

If you’re using it to pre-wash the car, then cleaning power is more important. If the foam is thin but cleans well, then there’s not really any issue.

If you’re using your foam cannon to layer shampoo over the car to clean it with a wash mitt, then dwell time is more important than thickness. As long as the shampoo stays on the car long enough for you to clean it without keep re-foaming the area, again the thickness is just a secondary factor.

How to Keep the Foam Cannon Working Properly

Here are some quick tips to keep your foam lance in good working order:

  • Rinse out the foam lance and fill with clean water after use, then connect it to your pressure washer and rinse it through for about 10 seconds before putting it away. This will help prevent the filter and pickup pipe becoming clogged.
  • Try not to leave snow foam in the lance to store it as it can clog up the pickup pipe.
  • Make sure you check for leaks periodically.
  • Clean the foam cannon (as described in point #6) at least annually.


Heather is a professional car detailer & valeter based in Cheshire and the owner of Auto Care HQ. A familiar face in the car detailing community, she has written over 200 car detailing guides on autocarehq.com and has produced over 165 videos on the Auto Care HQ YouTube channel.

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