Dehumidifier Drain Hose Connection Sizes

What the listing tells you

When you read a dehumidifier listing, the drain connection is usually described in the bullet list or the image set. Look for words like "drain hose," "continuous drain," "gravity drain," or "pump included." The listing may state the hose size in inches or show a picture of the fitting. If the size is not stated, the seller may have left it out, and you should check the maker's page or the manual.

The two common fitting types are a barb fitting, where a hose slides over a ridged spout, and a threaded fitting, where a hose or adapter screws on. The listing may not name the type, but the image usually shows it. A barb fitting is common on portable units; a threaded fitting is more common on whole-house or commercial units. For a general overview of drain options, see dehumidifier drain options.

• Barb fitting: a ridged spout that accepts a hose with an inside diameter of about 3/4 inch or 5/8 inch.
• Threaded fitting: a screw-on connection, often a standard pipe thread or a garden hose thread.
• Adapter: a small part that lets you connect the unit's fitting to a different hose size or type.

Common sizes and fittings

Portable dehumidifiers typically use a barb fitting that accepts a hose with an inside diameter of 3/4 inch or 5/8 inch. The hose slides over the barb and is held in place by friction or a small clamp. Some units use a threaded fitting, which may be a standard 3/4-inch garden hose thread or a finer pipe thread.

Whole-house and commercial units often use a larger threaded connection, such as a 3/4-inch or 1-inch pipe thread, because they move more water. The listing may state the thread size, or the maker's manual will. If the listing does not say, treat the size as unknown and confirm it before buying an adapter. For more on continuous drain setup, see dehumidifier continuous drain hose setup.

A standard garden hose has a 3/4-inch thread, which is different from a pipe thread. An adapter converts the unit's fitting to the garden hose thread, so you can run the drain line to a floor drain or outside using a regular garden hose.

Adapting to a garden hose

To connect a dehumidifier to a standard garden hose, you need an adapter that matches the unit's fitting to the garden hose thread. If the unit has a barb fitting, you slide a short piece of hose over the barb, then attach the other end to a garden hose adapter. If the unit has a threaded fitting, you screw on an adapter that converts to the garden hose thread.

The adapter is a separate purchase, not included with the unit. Read the listing to see if the unit comes with a drain hose or an adapter. If it does not, you will need to buy one that matches the unit's fitting size and the garden hose thread. For a guide to units with a pump, see best dehumidifiers with pump.

When you connect the hose, make sure the fitting is snug but not over-tightened. A loose connection can leak. The maker's manual will describe how to attach the hose and where to route it. If you are unsure about the fitting size, contact the maker with the model number.

Pump versus gravity drain

A gravity drain relies on the slope of the hose to carry water away. The hose must go downhill from the unit to the drain. A pump, when included, pushes water upward, so the hose can go up and over an obstacle. The connection size may differ between a gravity drain and a pump drain.

On a pump unit, the pump outlet is often a barb fitting that accepts a hose, and the listing may state the hose size. On a gravity drain, the fitting is usually at the bucket or the back of the unit. Read the listing to see which type you are getting, and check the manual for the exact connection. For more on pump benefits, see dehumidifier with pump benefits.

If you have a pump, the hose length and lift height are questions for the maker's page. The listing may state the pump's lift, but the connection size is separate. Always confirm the fitting size before buying a hose or adapter.

Checking the manual

The maker's manual is the final word on the drain connection. It will state the hose size, the fitting type, and how to attach the hose. The listing may not include this detail, so the manual is your best source. You can usually find the manual on the maker's website by searching the model number.

If you are comparing two units, check the manual for each to see the connection size. This helps you plan the drain setup before you buy. The manual will also tell you if the unit comes with a hose or if you need to buy one separately. For a broader look at choosing a dehumidifier, see best dehumidifier.

For any electrical work or drilling, such as routing a drain line through a wall, contact a licensed professional. The manual will describe the drain setup, but it will not cover modifications to your home.

What to pick for your situation

Questions

What size hose does a dehumidifier drain use?

Most portable dehumidifiers use a barb fitting that accepts a hose with an inside diameter of 3/4 inch or 5/8 inch. Some use a threaded fitting. The exact size is stated on the listing or in the maker's manual.

Can I connect a dehumidifier to a garden hose?

Yes, with an adapter that matches the unit's fitting to the 3/4-inch garden hose thread. The adapter is a separate purchase.

Is a drain hose included with a dehumidifier?

Some listings include a drain hose, others do not. Read the listing to see what is in the box. If a hose is not included, you will need to buy one that matches the fitting size.

What is the difference between a barb and a threaded fitting?

A barb fitting is a ridged spout that a hose slides over. A threaded fitting is a screw-on connection. The listing image usually shows which type the unit has.