Shop Vac Blowing Dust Out the Back? (Here's Why)

Ryan Womeldorf
by Ryan Womeldorf
A Shop Vac can come in handy for cleaning up after a project or if an area is particularly dirty. However, it can be troubling when your Shop Vac blows dust out of the back. This is generally due to a dirty filter, so follow along as we explore what you can do when your Shop Vac blows dust out of the back.

A Shop-Vac can be an extremely helpful, versatile outdoor vacuum. Clean up the garage in a flash, vacuum your car, or anything else that you can put your mind to. Shop vacs also tend to be very low maintenance, oftentimes having just a few components when compared to a traditional vacuum.

A Shop-Vac can blow dust out of the back if the filter is dirty or damaged. Clean the filter by hand, rinse it with water, let it dry for 8-12 hours, and put it back in the Shop-Vac. Replace the filter entirely if there is a hole in it.

Related Content: Can You Use A Shop Vac Without A Filter? | How To Use A Shop Vac For A Water Pump

Do You Need Post Construction Clean Up Services?

Get free, zero-commitment quotes from pro contractors near you.

Check the Buttons First

Depending on the model of shop vac that you have, it is entirely possible to have a button that can be set to either blow out air or suck it in. With this type of Shop-Vac, the simplest explanation is that it has been set to the wrong setting.

Do a quick check to see where the button is set. If it is the button, you can simply flip it to vacuum and go back to what you were doing. If this isn’t the cause, however, you will have a little bit more investigating to do.

Check the Filter

Now that we have done a little troubleshooting, we can safely say that the cause of the problem is the filter. The easiest way to get to the filter is by taking the top off of the Shop-Vac. Most models will typically feature a pair of clips holding the filter into place.

It could be as simple as a dirty, clogged filter. In the most extreme cases, you may simply find shreds of the filter left over. If you don’t check or change your filter for a long time, it can wear down and clog to the point that it actually begins to disintegrate.

Use a Vacuum Bag

While it is highly recommended that you do not use a Shop-Vac without a filter, it is up to you whether or not you use a bag. At the end of the day, using a bag will make cleanup far easier but it isn’t mandatory.

If you skip using a bag, the inside of the canister will be a huge mess that is far more difficult to clean up. Not only that, it can lead to a clogged filter far sooner rather than later.

Fixing the Filter

When the filter goes, the Shop-Vac will start blowing dust out the back, moving your mess from one portion of the room to the other. To save yourself the trouble, be sure to check out your filter time and again to ensure that it is working properly and in one piece.

Be Aware of Filter Sizes

Identifying your filter is an important step towards solving the problem. But you also need to keep in mind that not all shop vac filters are the same size or style. Most shop-style vacuums will take what is known as a VF4000 filter.

Double-check to see what size filter you have but they are relatively cheap to pick up and can even be had for half the cost depending on which online retailer you find versus in typical retail stores. Depending on your need, you can get them at a local store for immediate use.

Cleaning and Replacing Your Filter

The good news is that taking your filter out, whether it be to clean it or ultimately replace it, is super easy to do. All you need to do is snap the filter off of the middle plastic frame. You can shake it out, rinse it off, and let it dry out overnight before putting it back to use.

1. Snap off the old one. When looking to replace the old filter, you will need to snap off the old one. It can fight you a little bit since there’s a tight hole that the filter actually engages a knob set onto the frame. The knob is meant to hold the filter in place in the face of the high-speed of the vacuum winds. When you remove the old filter, simply slide the new one into place, making sure that it locks.

2. Put in the new filter. It can take a little bit of force to snap the new filter into place, so don’t be scared off if the new filter doesn’t just slide in.

3. Return the cover. Return the cover to the shop vac and you’re ready to use it again in short order.

A new filter can vary in length but should give your shop vac, even older models, new life again. Besides, it is far cheaper to replace the filter than it is an entire shop vac. Even if you have to pay a little more for a filter now, it will wind up saving you money in the end.

Upgrade Your Filter

Perhaps you have just purchased a new filter or your current one is in pretty good condition, yet the shop vac is still blowing out dust through the back. When this happens, it simply means that the dust you are vacuuming up is too fine for your current filter.

When it comes to finer debris or dust, like fine powders or cement dust, you will have to upgrade to the VF5000 or potentially a higher filter than that. A good rule of thumb to follow is that, if you can see the debris you’re about to vacuum, the VF5000 will do just fine.

Finer Filters

If you are concerned about pollen or pet dander, household vacuums have a finer filter to pick those things up. But if you don’t want to use your indoor vacuum for outdoor purposes, upgrading to a VF6000 filter should ensure that just about anything in your way will be completely vacuumed up.

For shop settings, where you are more likely to see tracked-in dirt or sawdust on a regular basis, go with a heavy-duty filter to be safe. It will save you a lot of hassle and extra cleanup time and won’t cost you that much more than a standard filter.

A Quick Prevention Tip

While it’s definitely helpful to know what to do in the wake of a dust problem, it’s always better if you can prevent the issue from happening entirely. That said, it is always helpful to shake the dust off of your filter each time that you use it.

While this may seem like a bit of a pain, it is actually a very small step to take to prevent the filter from becoming clogged or overly worn down. Even if you shake the filter out every couple of times that you use it, that should be enough to extend the life of your filter for a substantial period of time.

Do You Need Post Construction Clean Up Services?

Get free, zero-commitment quotes from pro contractors near you.

Related Questions

Can You Use a Shop-Vac without a Filter?

So, having read all of that, it is only natural that a few of you out there will ask the question: can you use a shop vac without the filter in it? Well, sure, you technically can but it probably isn’t going to turn out all that well for you.If at all possible, you should never use the Shop-Vac without a filter in it. The vacuum will continue to work but you will likely see a major reduction in vacuuming ability. Not only that, but no filter will likely clog up some of the components internally.

Can a Shop-Vac be Used to Vacuum Water?

Some consider it to be too big a hassle, but you can definitely use a Shop-Vac to vacuum up water if you have no other options. In a pinch, a shop vac should do fine to suck up water from, say, a broken pipe.If you plan on using it for larger areas or something like a pool, it likely isn’t worth the hassle. It shouldn’t do damage to your Shop-Vac, but it can mean needing to empty the unit way too often. It’s simply too much work and far too inconvenient.Consider the output hose. Another thing to keep in mind is that you should have an output hose if the situation allows for it. The output hose dispels the water out of the other input as quickly as you vacuum it up. This can make the process quicker, but you have to have a place to dispel the water in order for it to be truly effective.

Is There a Filter for Wet Pickup?

Should you plan on using your Shop-Vac for light wet work, it is important to get the proper filter for the job. The best filter for wet pickup is a foam sleeve filter. The foam sleeve will keep any debris from being able to reach the motor.Vacuuming areas with sharp objects. If you plan on vacuuming areas that are rife with glass or stones, you will want to make sure that you have a tear-resistant collection bag over top of the foam sleeve filter. That will stop the filter from getting ripped or destroyed by the glass and stones. Just make sure that you verify that the foam sleeve that you choose works for your shop vac.

Related Guides

Ryan Womeldorf
Ryan Womeldorf

Ryan Womeldorf has more than a decade of experience writing. He loves to blog about construction, plumbing, and other home topics. Ryan also loves hockey and a lifelong Buffalo sports fan.

More by Ryan Womeldorf