From what I’ve gathered through my own experiences, it’s pretty interesting to note that while you don’t always have to use a bag with a shop vacuum—especially when you’re dealing with something like water—opting for one can be a really smart move, particularly with dustier or grittier stuff.
Let’s say you’re tackling sawdust, a bit of dirt, or even tiny pebbles. In these cases, a bag inside your vacuum can be a total game-changer. It’s not just about trapping all that debris; it’s also about giving your vacuum an extra layer of defense. The bag acts like an additional filter, catching the finer dust and preventing it from clogging or overworking the main filter.
So, even though bags aren’t always necessary, I’ve found that in certain situations, they can make a world of difference.
If you do choose to use a bag, it’s important to know how often to replace it.
In general, you should replace the bag when it becomes full or when suction starts to decline.
You may notice suction decline when the bag is only halfway full, this is one of the drawbacks of using vacuum bags.
Use A Trash Bag Instead!
Tip: I use a trash bag in my shop vacuum when cleaning my gutters as it makes a big wet mess, which regular vacuum bags can't handle. This is not the natural state of my shop vacuum, as I rather run it bagless or trash bagless for most messes.
Sucking Up Water
You need to avoid having a bag in your shop vacuum if you’re sucking up water or any wet messes.
The bag won’t hold any water, and it will only make a mess.
In fact, the bags will get destroyed as the fabric itself is meant to be a filter and water will only clog and rip the bag. So don’t have the bag in your shop vacuum if you’re sucking up water or any wet messes.
No Filter When Sucking Up Water
If you’re sucking up water in your shop vacuum, you need to avoid having the paper filter on your shop vac.
Your shop vacuum should come with a foam filter, and that is the filter you use to suck up water and other wet messes.
Using the white paper filter will only work for a short time until it gets too wet and suction stops. The paper filter will also get destroyed in the process, only use the paper filter for dry messes.
You Get Better Suction Without Bag
You will get better suction from your shop vac if you don’t use a bag.
Bags can reduce suction power, and they also need to be replaced more often than the filter.
If you’re only using your shop vacuum for wet messes, then you don’t need to worry about the bags at all. Just make sure you have the foam filter in place, and you’re good to go.