Yes, you can drain a dehumidifier into your sump pump, but it requires the right setup
A dehumidifier and a sump pump both move water out of your basement, so connecting them seems logical. You can do this safely, but the connection matters. The water from a dehumidifier is clean condensation—not the groundwater or sewage that a sump pump normally handles—so it will not damage the pump. However, you need to run the dehumidifier drain line into the sump basin itself, not into the discharge pipe, and you need to make sure the connection does not let air into the basin or allow backflow into the dehumidifier.
The simplest and safest method is to run the dehumidifier's drain hose directly into the sump basin, where it sits above the water level. This way, the water drains by gravity into the basin, the pump activates when the water reaches the float switch, and everything works as designed. You do not need any special valves or fittings—just a hose that reaches from the dehumidifier to the basin opening.
Key Takeaways
- Dehumidifier water is clean condensation and will not harm a sump pump, so the two can share the same basin without damage.
- Run the dehumidifier drain hose into the sump basin itself, not into the discharge pipe that leads outside.
- Position the hose so it drains above the water level inside the basin to prevent backflow into the dehumidifier when the pump runs.
- If the dehumidifier sits higher than the sump basin, gravity will do the work; if it sits lower, you may need a small pump to move the water up into the basin.
- Check the hose connection monthly to make sure it has not shifted or become blocked, especially during humid seasons.
Where the dehumidifier hose connects inside the basin
The dehumidifier drain line must enter the sump basin above the water level. This is the critical detail. When you look inside the basin, you will see water sitting at the bottom—that is where the sump pump sits and where the float switch floats. The dehumidifier hose should come in through the basin opening and hang or rest above that water surface.
If the hose sits in the water, two problems happen: first, when the pump runs and the water level drops, the hose can siphon water back out of the basin and into the dehumidifier, which can damage it; second, if the hose gets submerged, air cannot flow freely through it, and the dehumidifier may not drain at all. Keeping the hose above the water line prevents both issues.
find the hose so it does not slip into the water or fall out of the basin opening. You can use a hose clamp, a piece of duct tape, or a small bracket to hold it in place. The goal is a stable connection that will not shift when the pump runs or when you walk past the basin.
Gravity versus pump-assisted drainage
If your dehumidifier sits on a shelf or table above the sump basin, gravity will pull the water down into the basin without any extra effort. This is the easiest setup. The hose straightforward slopes downward from the dehumidifier outlet to the basin opening, and water flows on its own.
If the dehumidifier sits on the floor at the same level as the basin, or lower, gravity alone may not be enough. In this case, you have two options: move the dehumidifier to a higher location, or add a small condensate pump. A condensate pump is a compact electric pump designed for exactly this job—it sits in a small reservoir under the dehumidifier, collects the water, and pumps it up into the sump basin when the reservoir fills. These pumps are inexpensive and widely available at hardware stores. They run on standard household current and are quiet enough for a basement.
What to avoid when connecting the hose
Do not connect the dehumidifier hose to the sump pump's discharge pipe—the pipe that carries water outside. The discharge pipe is under pressure when the pump runs, and connecting the dehumidifier there can cause backflow into the dehumidifier or create an air lock that stops the pump from working. The discharge pipe is also where a check valve sits, and adding another line upstream of that valve can interfere with its function.
Do not use a hose that is too small or kinked. A kinked or pinched hose will slow or stop the water flow, and the dehumidifier may not drain properly. A standard dehumidifier drain hose is usually 5/8 inch in diameter—use that size or larger, and keep the hose as straight as possible.
Do not leave the hose connection loose or unsecured. If the hose pulls free from the basin, water will pour onto your basement floor instead of into the pump. Check the connection every month, especially during summer when the dehumidifier runs constantly.
Seasonal maintenance for the combined system
Once the dehumidifier is draining into the sump basin, the basin will fill faster than it would from groundwater alone. This is not a problem—the pump will straightforward run more often—but it means you should check the pump more frequently during humid months. Make sure the float switch moves freely and is not stuck or blocked by debris.
If the dehumidifier hose becomes clogged, water will back up into the dehumidifier tank. To prevent this, inspect the hose every month and clear any algae or mineral buildup. You can flush the hose with clean water or run a thin brush through it. If the hose is cracked or deteriorated, replace it before it fails.
During winter, when humidity is low and the dehumidifier may not run, the sump basin will receive less water. This is normal. The pump will set up less often, but it should still run at least once every few months to stay in working order. If the pump does not run for several months, test it manually by pouring water into the basin to make sure it still works.
Checking that the sump pump can handle the extra water
A standard sump pump is sized to handle the groundwater that enters a basement naturally. Adding dehumidifier water increases the total volume the pump must move. In most cases, this is not a problem—a dehumidifier produces only a few gallons per day, and a sump pump can handle that easily. However, if your basement is very wet and your dehumidifier runs constantly, the pump may run more frequently than it did before.
Watch the pump for the first few weeks after you connect the dehumidifier. If it runs every few minutes instead of every few hours, the basin is filling too fast. This could mean the pump is undersized for the total water load, or it could mean the dehumidifier is working harder than expected because the basement is very humid. If the pump runs constantly, consider running the dehumidifier only during the day, or moving it to a smaller area of the basement so it does not have to work as hard.
Frequently Asked Questions
Will dehumidifier water damage my sump pump?
No. Dehumidifier water is clean condensation with no sediment or contaminants, so it will not clog or harm the pump. The pump is designed to move water, and this water is cleaner than the groundwater it normally handles.
Can I connect the dehumidifier hose to the discharge pipe outside?
No. The discharge pipe is under pressure when the pump runs, and connecting the dehumidifier there can cause backflow into the dehumidifier or create an air lock in the pump. Always connect to the basin itself, above the water level.
What if my dehumidifier is in a different room from the sump pump?
You can run a longer hose to reach the basin, but gravity must still pull the water downhill. If the dehumidifier is higher than the basin, a long hose works fine. If it is lower, you will need a condensate pump to move the water upward into the basin.
How often should I check the dehumidifier drain hose?
Inspect the hose connection and look for clogs or cracks at least once a month, more often during humid seasons. A clogged hose will cause water to back up into the dehumidifier tank, which can damage it.
Does connecting a dehumidifier to the sump pump increase my electric bill?
Yes, slightly. The sump pump will run more often because the basin fills faster. The increase is usually small—a few dollars per month—because the dehumidifier water is only a few gallons per day, and the pump is efficient.