How Does a Wet and Dry Vacuum Cleaner Work?

Today, let’s get a bit technical and discuss how a wet and dry vacuum cleaner works. With the knowledge about how these handy tools work, you will be able to utilize yours better and get the most out of it.

First, what is a wet and dry vacuum cleaner?

Wet Dry Shop VacThis is a multi-purpose vacuum cleaner designed to clean both dry dirt and liquid spills.

They were initially designed for heavy-duty jobs in commercial settings but have become more compact over time and made their way into homes, shops, and offices.

How Does a Wet and Dry Vacuum work?

Let’s first see how regular dry vacuums work;

A dry vacuum works by incorporating a vacuum bag that all the dirt and dust sucked up by the machine gets into, and this bag gets emptied after the cleaning gets done. But, there’s a limitation: this vacuum bag only takes in dry waste and can get spoiled if it sucks in liquid spills.

On the other hand, a wet and dry vacuum instead of a vacuum bag has a single bucket or a two-bucket system that separates liquids from solid waste sucked into the vacuum into two separate chambers. After cleaning, you can then empty both chambers separately.

For a wet & dry vacuum cleaner to work, several individual parts of it must function together to suck solid dirt and liquid spills. These parts include;

Motor power

This is what drives the suction process of the vac. A motor converts electrical energy from a source into mechanical energy that enables the suction of the vacuum. This is the most crucial part of the vacuum cleaner.


For the vac’s motor to function correctly, it requires electrical power. Some vacs have electrical cords plugged into external electrical outlets to feed power in real-time to the appliance, while some are cordless and get power from a battery.

Usually, having cords is preferable to get the best amount of electrical energy, and because most shop vacs require high energy, they have cords. Some other types of wet & dry vacs are cordless, but they generally perform less than shop vacs.

The power capacity of wet & dry vacs is usually listed in horsepower (hp) for corded ones and in volts (V) for cordless ones. Their ratings include;

  • Light Duty – 1 to 4.5 horsepower for corded ones and 18 to 20 volts for cordless ones. Having light power, they are ideal for small cleanup tasks around a home or in a car.
  • Medium Duty – These types have 5 to 6 horsepower motors for corded vacs and 20 to 24 volts for cordless ones. They’re suitable for cleaning after small construction and DIY works that generate a significant amount of debris.
  • Heavy Duty – These types are the big boys of their class, the shop vacs used to clean up heavy-duty construction sites that generate a lot of dirt and debris. They have the highest power requirements, being 6+ horsepower for corded ones. It’s rare to find a heavy-duty shop vac that’s cordless because of its high power requirements.

Storage Tank of a Wet and Dry Vacuum Cleaner-

Wet and Dry VacuumWhen dirt and debris are sucked by the vacuum into the machine, it goes into the storage tank (a bucket or canister) where it’s held until the vacuuming work is done and the tank is emptied. The bigger the storage tank, the bigger the amount of debris that can be stored at a time.

The storage tank capacity of wet & dry vacuum cleaners varies. They include;

  • Small capacity – These types hold anywhere from 0.5 to 6 gallons of debris, depending on the style. They are usually handheld wet & dry vacs.
  • Medium capacity – Some have storage tanks that can hold anywhere from 6 to 14 gallons of debris, making them suitable for cleaning up dry debris in workshops or large amounts of stagnant water in homes and offices. These are usually the upright vacuums.
  • Large capacity – These types have storage tanks that hold 14 gallons of debris and upwards. They are the high-powered shop vacs used to clean up heavy-duty construction sites.


Wet & dry vacs are heavy and have wheels to move around. This is important when doing tasks such a vacuuming spilled water since the appliance can get very heavy.

Hose Length

The length and diameter of hoses in a vacuum cleaner determine the amount of waste that can be sucked at a single time where the vacuum remains stationary. If the hose is long, you won’t need to move it around as frequently as you would do when the hose is short.

The hose length of a vacuum usually runs from anywhere between 6 and 30 feet, depending on the type.


All vacs have filters that serve different purposes. For wet & dry vacs, you have to switch filters from dry to wet and vice versa whenever you want to clean because there are different filters for both purposes.

For dry cleaning, you use a paper filter to trap dust and small bits of debris to prevent them from recirculating back into the air, while for wet cleaning, you use a foam pre-filter that prevents large particles from entering into the corrugated filter.


Wet & dry vacs usually have accessories that enable external attachments to expand the vac’s functionality. With attachments, vacs are able to do more than they can in their stock mode from the manufacturer.

The types of attachments that wet & dry vacs support include;

  • An elbow wand for reaching around corners or overhead.
  • A brush nozzle for cleaning car interiors.
  • A blower attachment to blow leaves or snow away.
  • A crevice nozzle for sucking debris out of tight corners and spots.
  • Reusable or single-use waste bags.

The Working Principle of  A Wet and Dry Vacuum Cleaner

Given these parts, we can discern how a wet & dry vacuum works.

  1. The vac is powered by plugging it into an external electrical outlet or a battery.
  2. Electrical energy is then fed to the motor that converts it into mechanical energy to enable the suction function. The suction function works via a high-spinning fan sucking in air and any other particles within its vicinity and pushing them into the storage tank
  3. The vac sucks in dirt and debris into its storage tank and does so until the cleaning job is done or the tank gets full; during the cleaning process, the filters work to prevent small dust particles from recirculating into the air (dry cleaning) or prevents large particles from entering into the corrugated filter (wet cleaning).
  4. After cleaning, the storage tank is emptied for use again.
  5. During cleaning, several attachments can be used to enhance the job, e.g. crevice nozzle for sucking dirt out of tight corners or blower attachment for blowing leaves or snow away.

The best way to illustrate how a vac works is a straw. When you sip a drink with a straw, you create negative air pressure inside it. That’s lower than that of its surrounding atmosphere and thus sucks the drink into your mouth. It’s the same way with a vacuum cleaner sucking in dirt into its storage tank, pausing and repeating.

What are the uses for a wet and dry vacuum cleaner?

Because they’re capable of cleaning both liquid and solid waste. Wet and dry vacuum cleaners offer more cleaning functionality than dry vacuum cleaners in areas including;

1.    Cleaning water spills

Water spill accidents in a home aren’t unheard of, maybe from a tap left running or even from flooding. In such a case, wet and dry vacuum cleaners effectively help clean up the mess.

2.    Unblocking baths and sinks

Clogged-up baths and sinks are common incidents in homes. To solve this problem, you can use the blower function of a wet and dry vacuum cleaner to remove the blockages by applying considerable external force.

3.    Cleaning carpets

Carpets in a home are prone to absorb liquid spills due to their texture. You can use wet and dry vacuum cleaners to get rid of the absorbed liquid spills effectively.

4.    Emptying water mattresses

Do you own a water mattress? This is sort of a trick, but you can use the suction function of wet and dry vacuum cleaners to empty water mattresses when you need them to be as dry as possible.

5.    Clearing snow and leaves outdoors

With their blower function, wet and dry vacuum cleaners effectively blow snow and fallen leaves away from an outdoor setting, maybe your gardens or front yard.

Other handy uses of these vacuums include cleaning ashes and dust from a fireplace and blowing dust from curtains.

Types of Wet & Dry Vacuum Cleaner

Wet & dry vacuum cleaners are of several types, including;

1.    Shop Vacuums

This is the particular type most commonly used in construction and woodworking. It contains a high-powered suction unit that sucks heavy dirt and debris, the type commonly found in construction sites and woodworking shops. These types have big and rigid hoses to suck up large amounts of waste and large canisters to hold the sucked-in waste.

One of the standout features of shop vacs is the blower function.

 By look, shop vacuums look like buckets with a vacuum attached, and for that reason, they’re aptly called bucket vacuums. Because of their heftiness, they usually have large wheels to help move them around construction and woodwork sites quickly to clean dirt.

Shop vacs differ from regular vacuums because they’re built for heavy-duty work, with enough motor power to suck up the type of hefty debris found in industrial sites. Unlike regular vacuums, they also don’t use bags to store the dirt but rather the buckets attached to the machine that you can empty after use.

Lastly, shop vacs don’t have filters like regular vacuum cleaners as it’s capable of sucking up dirt without separating hefty chunks of it. Due to their high power consumption, they are also mostly corded (plugged into electrical outlets to function).

Shop vacs due to their complexity are the most expensive type of wet & dry vacuums.

2.    Handheld

This type of vacuum is portable enough to be held firmly on the hand while vacuuming. Because of its portability, it’s easy and quick to clean up small amounts of dirt, able to suck in only small amounts of water and dust at a single time.

Handheld vacuums are commonly used in homes and offices. Due to their low level of complexity, they are the cheapest type of wet & dry vacs to purchase.

3.    Upright Vacuum (Cordless)

These vacuum cleaners aren’t as portable like the handheld ones or as big as the shop vacs. They are instead of medium size and are usually cordless, capable of getting pushed around quickly without restrictions and absorbing the ideal amount of dirt produced in homes and offices.

Upright vacuums are not as expensive as shop vacs nor as cheap as handheld vacs. They are priced in the medium range.

Frequently Asked Questions About Wet and Dry Vacuum Cleaners

Is a shop vac the same as a wet and dry vac?

Though both terms are used interchangeably, a shop vac isn’t always the same as a wet and dry vac because some shop vacs don’t actually have the wet suction function.

Can I vacuum water with a shop vac?

Many shop vacs have a wet suction function, meaning you can vacuum water with them.

Is a shop vac more powerful than a regular vacuum?

Yes. Generally, a shop vac is more powerful than a regular household vacuum.

Can a wet and dry vac clean carpets?

It’s often the tool of choice to suck water out of flooded carpets. However, it’s not a dedicated carpet cleaner.

How do you maintain a wet & dry vacuum cleaner?

Regular cleaning, safe storage, always empty the storage tank immediately after use, etc.