How to Use a Wet Dry Vac on Commercial Jobs (Setup, Wet Pickup, Squeegee, Filters)

Rod Michelini is the founder of OneUp Cleaning. We sell the Tornado, Powr-Flite, Viper, Clarke and NaceCare machines named here, so every wet vac setup step below follows its manufacturer's own manual, and where an auto scrubber does the job better, this page says so.

To use a commercial wet dry vac, set it up for the mess first: dry filter in for dust, dry filter out (wet filter or foam sleeve on) for water, unless it's a dual-filter model that keeps both in. Pull the tool slowly and flat, stop when the float cuts suction, and add defoamer for soapy liquids, because foam slips past the float.

That's the whole job for a clean-water spill. Read on if you're picking up stripper, running a front-mount squeegee, or wondering why water is spraying out of the exhaust.

How do you set up a wet dry vac for dry or wet pickup?

Inside your machine, a bypass motor separates the air pulled through the tank from the air that cools the motor, and a float in a wire cage under the head blocks the inlet when the tank fills. That's how the Powr-Flite manual describes it, and what covers that cage is the entire difference between dry and wet pickup.

Setting up for dry pickup

Fit the cloth dry filter, reattach the head and lock the clamps, because you should never vacuum dust without it. The Tornado Taskforce manual identifies a dirty, torn or missing cloth filter as the reason dust blows out of the unit. On the Viper Shovelnose, the cloth bag is an optional accessory that Viper tells you to replace at three quarters full.

How to convert a wet dry vac from dry to wet

1. Empty the tank first, as Nilfisk recommends before switching between dry and wet operation.
2. Remove the cloth dry filter. Four commenters on two YouTube wet vac videos left theirs installed and either lost suction with the tank half empty or ruined the filter.
3. Fit your model's wet filter. On the Powr-Flite PF57, the pleated paper filter comes out too, and the float cage stays on. The Viper uses a nylon foam bag, and the Viper manual warns that operating without it voids your motor warranty.
4. Check that the float moves freely before you lock the head down.

If you run a dual-filter machine, you skip steps 2 and 3, and Nilfisk names the Clarke Maxxi II 35 as one of them. The Clarke manual says the Maxxi II 35 keeps its cartridge filter, wet filter and float in place for both wet and dry work, and NaceCare's spec sheet says the CV 570 picks up wet and dry without you changing filters. You still empty the tank between jobs.

Here's that setup on the seven machines in our commercial wet dry vacuums range:

Our prices as of October 14, 2026.

Notice that your wet capacity isn't your tank size. Tornado's specification sheet rates the Taskforce 20 at 15 gallons of working capacity in a 20 gallon tank, and the Taskforce 10 at 5 gallons in a 10 gallon tank, because the float shuts off suction before the drum is completely full.

How to use a wet dry vac for water

Can a shop vac suck up water? Yes, once the dry filter is out and the float moves freely.

Technique that keeps suction on the water

Plug into a grounded outlet and keep the cord behind you, away from spilled liquids. The Viper manual prohibits extension cords entirely, and the machine ships with a 50 foot cord, while some household guides allow a wet-rated extension, so follow your owner's manual.

No outlet near the spill, or a cord that would cross a walkway? Our cordless pick is the NaceCare WVB 370NX (from $1,499). It runs up to 40 minutes on an NX300 battery and holds 2.4 gallons of water. That handles a spill, not a flood. For a whole room of water, the corded CV 570 or a pump is faster.

Work your way around the edges of the puddle or standing water first, then the middle, in slow overlapping pulls. Nilfisk's advice is to move steadily and keep the nozzle in contact with the floor, because a tilted nozzle pulls air instead of water.

When the float shuts it off

You'll hear the motor pitch change as suction stops, because the float has cut off airflow at the inlet. The Powr-Flite manual warns that the power stays on when this happens, so switch off and unplug before you open the head.

If suction stops while your tank is only half full, check that the float moves freely, as both troubleshooting charts advise.

How to empty the tank on a wet dry vac

You tip the Taskforce 15, Taskforce 20 and PF57 on their carts and pour, open the rear drain hose on the Viper, and lift and pour the smaller Taskforce 10, Maxxi II 35 and CV 570 by hand. Water weighs 8.34 pounds per gallon, so a Taskforce 20 at its 15 gallon capacity holds roughly 125 pounds of water.

At its 5 gallon wet capacity, a Taskforce 10 holds about 42 pounds of water you'll lift by hand, so empty the tank early when the drain is far away.

How to use a wet vac squeegee (front-mount and wand)

A mop spreads your dirty water around, while a wet vac with a squeegee removes it, and five custodians on Reddit make exactly that point, one noting that a mop only pushes the dissolved soil around.

The Taskforce 20 and the Shovelnose carry a front-mounted squeegee (it's an option on the Taskforce 15 and PF57), and on the Viper you lower it with the foot pedal and raise it for transport. Walk your machine forward in straight, slightly overlapping lanes, then use the squeegee attachment on the wand for edges and tight spaces, as one expert custodian recommends. On the Maxxi II 35 and CV 570, you squeegee with a floor tool on the wand instead: the rubber strip floor nozzle on the Maxxi, the 16 inch wet floor tool with squeegee blades on the CV 570.

Wipe your blades with a cloth, never your fingers, and store the machine with the squeegee raised, following the Viper manual.

Here's the honest concession: if you clean a large open floor every day, an auto scrubber scrubs and recovers in one pass and will beat any wet vac on time, so see how to use a floor scrubber. Your wet vac earns its place on floods, stripping jobs and rooms a scrubber can't reach.

Not sure which fits your facility? Send your square footage, floor type and what you pick up through the contact page for a straight recommendation.

Why foam is the one thing the float can't stop

The float rides up on liquid, but foam doesn't lift it the way water does, so the suds climb past the float toward your motor.

Viper's manual says it outright: "Foam will not activate the float shut-off, and therefore, may cause vacuum motor damage." Powr-Flite's warranty terms exclude motor damage caused by failure to use defoamer. Both Tornado and Powr-Flite list foamy liquid as a reason water blows out of the unit, with one remedy: add defoamer to the tank. The Clarke manual says to always use a chemical defoamer when your water holds foaming detergents.

Picture your crew stripping a school hallway, with the slurry foaming as it enters the drum. The suds rise past the float, mist sprays from the exhaust, and eventually foam reaches the motor. A capful of defoamer before the first pull would have prevented all of it.

Six custodians on Reddit describe that routine: a capful of defoamer in the tank, or about 8 ounces pulled through the hose beforehand. You'll need it for stripper, scrubber detergent, carpet shampoo and anything else that produces suds.

Picking up floor stripper: filters in or out?

In. Most online guides tell you to remove the filter for any wet pickup, but the Tornado and Powr-Flite manuals make a specific exception: "When picking up floor stripper with these units it is necessary to use all filters." Afterward, rinse your filters and the float cage thoroughly and let them air dry.

Under one YouTube stripping video, a contractor told a Tornado owner that he removes the dry filter for slurry because it gets messy. That keeps it cleaner, but your warranty is written against the manual, so follow it and rinse afterward.

More than seven custodians on Reddit prefer a front-mount squeegee wet vac to an auto scrubber for stripper, though in one r/Custodians discussion an expert says his district has used scrubbers for over a decade without a failure.

Either way, clean your squeegee, hose and tank the same day, because three custodians and that same contractor warn that leftover wax congeals, hardens and clogs the vac.

Wet vac filters: which one, and how to clean it

Do you leave the filter in a wet dry vac when vacuuming water?

Usually not the dry one. Remove the cloth or paper dry filter and leave your model's wet filter or foam sleeve on, with stripper as the exception. If you run a dual-filter machine like the Maxxi II 35 or CV 570, yes: you leave everything in.

Users disagree about the foam sleeve. Keep it on when your water carries dirt or debris, because without it, commenters say, grime can reach the blower intake and even the motor.

How to clean a wet dry vac filter

Ridgid tells you to rinse its wet filter without high water pressure and let it dry completely, and Powr-Flite gives the same instruction. Tornado's own video shows the Taskforce 15 filters rinsed from the inside out with a garden hose.

Let everything dry completely before the cloth dry filter goes back on, or you'll be vacuuming dust into damp cloth. The CV 570 manual says the same: don't refit a filter until it's completely dry.

How to clean and store a wet vac after the job

1. Drain and rinse your tank, then rinse the hose and tools, which five users say keeps mildew and odors away.
2. Clean the float after each use and rinse the foam bag after every wet job, as the Viper manual directs.
3. Store the machine with the head off so the tank can ventilate, which Viper says prevents odors.
4. Let everything dry before reinstalling the cloth dry filter.

Common questions

Why is my wet vac spraying water out the exhaust?

Usually because your tank is full or you're picking up foam. One Reddit user adds a third cause, a missing or twisted inlet deflector, so empty the tank, add defoamer and check the deflector. The Clarke and CV 570 manuals both tell you to switch off right away if foam or liquid comes out of the machine.

Can you just vacuum dry debris with a wet dry vac?

Yes, with the cloth dry filter installed and your tank dry, using the crevice tool and brush like any vacuum. If dust blows from the exhaust, the cloth is dirty, torn or missing.

Can I use a wet vac on carpet?

For spills, yes, but for deep cleaning, read our guide on using a shop vac as a carpet extractor.

For spot work on stains, stairs and seating, a carpet spotter sprays, scrubs and extracts with one tool. Our cordless one is the NaceCare CTB 370NX (from $1,549). It uses cold water only, so treat it as a spot tool, not a hot water machine. You can compare it with the other carpet spotters we carry.

Can a wet vac pick up gasoline or hot ash?

No. The Tornado, Powr-Flite, Viper and Clarke manuals prohibit flammable liquids such as gasoline, and the Powr-Flite, Viper, Clarke and CV 570 manuals also rule out anything burning or smoking, such as cigarettes and hot ashes.

Still deciding which of our commercial wet dry vacuums fits? Send your square footage, floor type and what you pick up through the contact page, or call (855) 601-5678. Every order is covered by our 30-day return policy, so you can confirm the fit on your own floors.

Related reading: Commercial wet dry vacuums · Floor scrubber maintenance · How to use a carpet extractor · Professional tile and grout cleaning machines · How to clean commercial tile floors