We may be compensated if you purchase through links on our website. Our team is committed to delivering honest, objective, and independent reviews on home products and services.
Project details
Skill
Cost
Estimated Time
PVC pipe cutter
Screwdriver
Your dehumidifier handles nasty moisture buildup and prevents mold, but emptying its tank can be a nasty and difficult chore. You can avoid this task completely by installing a new dehumidifier pump, which automates tank-emptying. Read how to install and maintain a dehumidifier pump in the step-by-step guide below, and watch the video above for tips from This Old House plumbing expert Richard Trethewey.
What is a Dehumidifier Pump?
Dehumidifier pumps automatically remove water from your dehumidifier and eliminate the need for manual emptying. These pumps are especially useful in basements or areas from which gravity drainage isn’t possible.
How Dehumidifier Pumps Work
A dehumidifier pump sits in the unit’s water reservoir and becomes active when the water reaches a certain level. The pump’s float rises with the water level, which triggers a switch that turns on the pump. The pump expels the water through a discharge hose, which you can direct to a suitable drainage point.
What Are the Benefits of Installing a Dehumidifier Pump?
Installing a dehumidifier pump offers several advantages:
- Allows you to remove water even when gravity drainage isn’t an option
- Offers greater convenience, especially in hard-to-reach areas
- Operates continuously without the need for manual intervention
- Reduces risk of water overflow and potential damage
Preparing for Installation of a Dehumidifier Pump
Gather all the tools and materials you need before you install the pump.
Tools and Materials Needed
You’ll need the tools and materials below to install a dehumidifier pump:
- Brass barbed fitting
- Clear plastic tubing
- New dehumidifier pump
- PVC coupling
- PVC pipe cutter
- PVC primer and cement
- Screwdriver
- Stainless steel hose clamps
- T-fitting
- U-shaped pipe clip
Assessing Your Setup
Keep existing drain lines, such as those that stem from air conditioning units, in mind while you set up your pump. These may provide an ideal connection point, which can simplify the installation process.
Step-by-Step Dehumidifier Pump Installation Process
Follow the steps below to install your dehumidifier pump:
1. Use a PVC pipe cutter to slice into the existing PVC drain line that runs from the air conditioner pump.
2. Attach a T-fitting to a new length of PVC pipe using PVC primer and cement. Fasten a brass barbed fitting to the T-fitting.
3. Connect the new pipe to the existing PVC drainpipe with a coupling. Glue the connection together with primer and cement.
4. Secure the new drainpipe to a floor joist with a U-shaped pipe clip.
5. Connect the existing tubing that comes from the air conditioner pump to the end of the PVC pipe.
6. Run a new length of clear plastic tubing from the T-fitting back to the dehumidifier.
7. Force one end of the tubing onto the barbed fitting that protrudes from the T-fitting on the PVC drainpipe. Secure the tubing with a stainless steel hose clamp.
8. Clamp the opposite end of the tubing to the discharge port on the new dehumidifier pump.
9. Unplug and remove the old defective dehumidifier pump.
10. Set the new pump into the dehumidifier condensate tub, then plug the pump into a GFCI-protected electrical receptacle.
11. Pour water into the condensate tub so that the pump operates properly.
Gluing PVC Connections: When assembling PVC joints, Richard Trethewey recommends cleaning both the pipe and the fitting first, then applying solvent cement and holding each joint for a quick three count before moving on. As he demonstrated on Ask This Old House, “My last connection is the coupling, clean both sides and the pipe and the old pipe. I’m gonna glue this all at once.” Taking the time to properly clean and cement each connection ensures a watertight seal.
How To Test and Troubleshoot Your Dehumidifier Pump
Once you’ve completed your installation, you should test your dehumidifier pump.
Performing a Test Run
Follow the steps below to test your new dehumidifier pump:
- Pour water into the dehumidifier’s condensate tub.
- Observe how the pump operates as the water level rises.
- Make sure the pump activates and successfully removes the water.
- Check all connections for leaks.
Pro Tip: Richard Trethewey, plumbing and heating expert on Ask This Old House, emphasizes the importance of electrical safety during testing: make sure your dehumidifier pump is plugged into a ground fault circuit interrupter (GFCI) outlet. As he notes, “That’s really important around water.”
Expert Insight: Every condensate pump discharge line should include a check valve. As demonstrated on Ask This Old House, a check valve contains a small flapper that lets water flow in one direction only — up and out of the building. Without one, water remaining in the pipe after the pump shuts off will fall back down, causing the pump to cycle on again unnecessarily and reducing its lifespan.
What Are the Most Common Issues With Dehumidifier Pumps?
Below are the most common issues you might encounter with dehumidifier pumps, and how you can address them:
- The pump doesn’t activate: Check the float mechanism and make sure the pump is plugged in.
- There’s insufficient water removal: Make sure the discharge hose isn’t kinked or obstructed.
- Unusual noises: Check for debris in the pump or loose components.
- Water leaks: Inspect all connections, and tighten or reseal as necessary.
Pro Tip: Richard Trethewey, This Old House plumbing and heating expert, has seen a common homeowner mistake that leads to pump failure: plugging the dehumidifier pump into a switched outlet. As he explains, homeowners sometimes “plug these pumps into a light socket or an outlet that’s switched and when they leave the basement and turn off the switch, they’re unaware they’ve shut off the pump.” He recommends a dedicated line for each pump, noting that a 15-amp service is adequate.
Maintenance and Care of the New Dehumidifier Pump
Take good care of your dehumidifier pump so that it continues to work efficiently.
Routine Cleaning
Follow the steps below to keep your dehumidifier pump in top condition:
- Clean the pump and reservoir each month with a mild detergent solution.
- Inspect and clean the discharge hose to prevent clogs.
- Remove any debris or buildup from the float mechanism.
When To Replace Your Pump
Dehumidifier pumps are usually durable, but you may eventually need to replace them. Consider replacing your pump if you encounter any of the following variables:
- It fails to activate consistently.
- The pump makes unusual noises or vibrates excessively.
- There are visible signs of wear or damage.
- You notice a significant decrease in pumping efficiency.
