Most dehumidifiers come equipped with a bucket that acts as a reservoir to catch water. When the bucket is full, the extra weight trips a float switch, and the unit shuts off until you empty the bucket. In humid weather, the bucket can fill in a matter of hours, and if you aren't around to empty the bucket, the appliance won't work until you return. To prevent this scenario, most manufacturers provide a hose thread adapter to which you can attach a garden hose. It may be already there on the back of the machine or the bucket, or you may have to install it.
Unplug the dehumidifier.
Look for a hose thread connection on the back or on the bucket. Not all units come with these installed, but if yours has one, you can simply screw on a garden hose. Instead of an adapter in place, some models have a hole into which you must screw the adapter, which usually comes with the unit. The hole is usually covered by a rubber plug.
Pull out the plug, insert the adapter and secure it with the screws that come with it, using a screwdriver.
Connect the drain port to the adapter with 1/2-inch plastic tubing. This tubing comes with the hose adapter; if you lost it, purchase a piece that is approximately 12 inches long. If the adapter is connected to the bucket, you don't need to install this hose.
Place the dehumidifier on a level surface at a higher elevation than the drain into which you want the water to empty. Check the level with a torpedo level, and if the dehumidifier is tilted, place shims under it to level it.
Thread a garden hose into the threaded drain port and extend the hose to the drain. Make sure the hose has no upward slope at any point along its path, or water will back up from that point.