How Do Portable Dishwashers Drain? – Complete Answer

For those who don’t have enough space to install a full-size dishwasher, there are convenient options – countertop and portable dishwashers. They do the same job as a standard or built-in dishwasher in washing dishes but are more compact, use less water and energy, and can be stored in a cabinet after each use.

Portable or countertop dishwashers drain into a sink. However, if you cannot install your dishwasher near a kitchen sink, you can use a drain hose to drain the water through an opening at the bottom of the dishwasher.

Since a portable dishwasher can be used as a countertop dishwasher (occupying your kitchen counter space) or placed under the sink or the counter, how the water drains depends on the place settings.

Portable Dishwasher Drain

So, how do portable dishwashers drain? Here are the different ways the wastewater expels out:

Unicouple Fitting And Timer-Controlled Pump

Most portable dishwashers fill and drain water through a special fitting called a unicouple connected to a sink faucet.

It has two hoses that connect to the dishwasher. One is an inlet hose that supplies cold or hot water from the kitchen faucet, and the other drains water from the dishwasher into the sink.

The dishwasher’s electric timer opens the drain valve upon completion of the wash cycle or a rinse cycle. Then, it reverses the circulating pump to expel the dirty water from the drain hose and the unicouple’s discharge outlet to drain into the kitchen sink.

Drain Hose

Some portable dishwashers have a built-in water tank and don’t need to be hooked to any sink’s faucet. Such dishwashers don’t need to be used near a sink necessarily.

A drainage hose can drain water into a sink or any drain (sink, floor drain, or shower).

However, dishwashers expel the water at relatively low pressure; this could be an issue if the water draining needs to go above the level of the dishwasher (when you place the dishwasher below the drain level). A model with a strong pump will help drain properly in this case.

Helpful Tip: You can even use a garden hose (with a pressure of at least 100 PSI) to supply and drain water if you install your dishwasher in the basement or near a utility sink.

Dishwasher Venting

Some dishwasher drain hoses are a few meters long and can be looped (a high loop) to prevent sink wastewater from backing into the dishwasher.

Some other drain hoses are designed for use with an air gap or by installing a check valve for the same purpose.

Draining Into A Tub or Bucket

A portable dishwasher (especially the countertop dishwasher) can be set up to drain directly into a tub or bucket placed at a slightly lower level next to the drain valve.

This might be a good option for portable dishwashers with a smaller capacity to avoid a messy situation.

Garbage Disposal

Portable or countertop dishwashers work by expelling dirty water through a hose and don’t use traditional plumbing.

This means that a portable dishwasher doesn’t need a garbage disposal.

It is good practice to rinse off any food waste from your dishes before loading them into your dishwasher to avoid any clogs.

Do All Portable Dishwashers Need A Drain?

Generally, all portable dishwashers do need a drain to empty the water and are installed to do so into a sink or any drain. If convenient, you can also permanently connect a portable dishwasher to a water source and drain.

However, some mini portable dishwashers don’t need any plumbing.

Instead, you can make do with a collapsible bucket or tub to supply water and even drain.

Tips On How To Use A Portable Dishwasher Without A Drain

One of the primary purposes of having a portable dishwasher is the convenience of using it anywhere. This might include a setup without a drain in the worst-case scenario.

Here’s how you can use a portable dishwasher without a drain:

  1. Use a container (like a bucket, tub, or external tank) to store the dirty water.
    Don’t forget to empty the container after each use.
  2. Use the dishwasher outdoors.
    However, this isn’t highly recommended since the expelled water contains chemicals from the detergent used, and there’s also the possibility of rust and corrosion.

You can find also a lot of helpful tips on how to use a portable dishwasher here.

Portable Dishwashers With A Great Drain System

If you’re looking to buy a new appliance with a smaller footprint to get your dishes done, here are some portable dishwashers with a great drain system.

Farberware Professional Portable Countertop Dishwasher

This portable countertop dishwasher has six place settings, seven washing programs, and an extra-drying function. A speed cycle gets your dirty dishes cleaned in just 45 minutes.

With a 6-ounce capacity, it can hold a variety of dishes up to 10-inches in diameter. The accessories and adapters are included to make it easy to connect directly to a faucet, and it can be used in apartments, campers/RVs, and dorm rooms.

You can choose to connect this to a sink or cut the connector off the hose to connect directly to a waterline using a PEX pipe. With a drain hose placed in the sink, it pumps out water just like a regular dishwasher.

GE 24-Inch Freestanding Dishwasher

This portable countertop dishwasher offers the convenience and capacity of a full-size dishwasher. Its spacious interior can hold up to 12 place settings at a time. This machine is mounted on swiveling caster wheels for easy portability.

Its Piranha hard food disposer pulverizes food particles and prevents large particles from clogging the wash arms or drains. This Energy-certified portable dishwasher offers a choice of five wash cycles and has a low noise level (about 54 decibels).

Another advantage is its adjustable top rack to accommodate larger pots and pans on the bottom rack.


A common problem for those with smaller kitchens or insufficient space is they can’t keep a standard dishwasher to clean dishes. The alternative is to use a portable or countertop dishwasher that can clean dirty dishes just as well as a regular dishwasher.

With a connected hose for the water supply and another for draining, you can get your portable dishwasher to work just as efficiently as the standard ones.