Tools and Materials
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Installing a Dishwasher Drain Hose
If you notice bad odors from your dishwasher, a clogged or leaking drain hose, replacing the dishwasher drain hose can be a relatively simple fix. Just make sure your new hose fits the connections we describe below.
In this guide we show you how to replace a dishwasher drain hose on an existing dishwasher. Exact steps vary by dishwasher and code requirements. Follow your local codes and the instructions for your specific dishwasher. Use these steps as a general guide. If you don’t have your dishwasher manual, note your dishwasher model number and check the manufacture’s web site for the manual.
If you’re installing a drain hose with a new dishwasher, take a look at our guide on how to install a dishwasher.
Step 1: Turn Off the Water and Power
Turn off the water supply to the dishwasher. If there’s not a separate supply valve for the dishwasher, turn off the water to your home. Turn off the circuit breaker for the dishwasher and, if you have one, the garbage disposer. Check to ensure there’s no power going to the appliances.
Step 2: Locate the Drain Hose Connections
Locate the dishwasher drain hose under the sink. There are several possible connection points for the drain hose:
- With a dishwasher-to-drain connection, a dishwasher drain hose installs to a small dishwasher drain port on your sink drain pipe.
- If you have a garbage disposal, the dishwasher drain hose might connect to a port on the disposer.
- The dishwasher drain hose might connect to an air gap device that has a separate hose running to the drain pipe or disposal. The air gap prevents dirty drain water from entering your dishwasher.
Note how the hose routes through the cabinets to the dishwasher so you can route the new hose along the same path. Now locate the connection at the discharge port on the dishwasher.
You might need to move the dishwasher out from under the countertop to access the port. If you need to move the dishwasher, first remove the mounting brackets securing the dishwasher to the countertop. If necessary, carefully disconnect the water supply hose. Move the dishwasher out from under the cabinet.
Step 3: Install an Air Gap, if Necessary
If your code requires an air gap but you don’t have the device, install it before connecting the new drain hose. Follow the manufacturer’s instructions. Typically, you bore a hole in the countertop near your faucet, secure the air gap device to the countertop and add the decorative cover. Connect the air gap outlet to the dishwasher T on the sink drainpipe.
Step 4: Disconnect the Existing Hose
Place a small bucket or shallow pan under the drain hose connection at the sink. Loosen the clamp securing the hose and carefully pull the hose end away from the connection. Let any water drain into the bucket or pan.
Place a cleaning cloth under the discharge port on the back of the dishwasher and remove the clamp securing the drain hose to the discharge port. Carefully drain water from the hose into the bucket or pan. Remove the hose from the drain loop on the back of the dishwasher, if equipped. Check the dishwasher manual for instructions specific to your model. Pull the existing hose out from the cabinet and from under the countertop, being careful to collect any water that remains in the hose.
Step 5: Connect the Dishwasher Drain Hose at the Sink
Place a hose clamp over the sink-end of the new drain hose. How you connect a dishwasher drain hose at the sink end of the hose depends on your setup. If you didn’t note the connections before removing the existing hose or if you installed a new disposal or air gap, here’s how you make the connections:
- How to Make a Dishwasher-to-Drain Connection: To connect a dishwasher drain hose to a sink, or more accurately, a sink drain, locate the dishwasher drain port, the small extension on the sink drain pipe. Slide the drain hose onto the port and clamp the hose securely in place.
- How to Connect a Dishwasher Drain Hose to a Disposal: Locate the dishwasher drain inlet on the disposal, typically near the top of the device. If this is a new disposal, you need to remove a plug from the inlet first. Slide the new hose onto the inlet and clamp it securely.
- How to Connect a Dishwasher Drain Hose to an Air Gap: An air gap has two fittings, a larger one that connects to the sink drain or disposal and a smaller one for the dishwasher hose. Connect the dishwasher drain hose to the smaller fitting and secure it with the clamp. Ensure there’s a hose clamped securely — with no kinks — between the larger fitting and the drain or disposal, according to the manufacturer’s instructions.
Step 6: Create a High Loop, If Necessary
If your codes don’t require an air gap, you need to create a high loop in the drain hose to prevent backflow and to keep odors from escaping. Check your codes to ensure they allow a high loop. Use plumbing hanger tape — a long metal strap with screw holes — or clamps to suspend a loop of the drain hose as high as possible under the countertop. Typically, the loop must be at least 32 inches above the floor.
Step 7: Connect the Dishwasher Drain Hose at the Dishwasher
Route the drain hose through the cabinets to the dishwasher location, ensuring there are no kinks or tight bends. Run it through the drain loop on the dishwasher, if equipped. Add a clamp to the end of the hose and connect the hose to the discharge port on the dishwasher. Secure the connection with the clamp.
Step 8: Check for Leaks
If you disconnected the supply line, reconnect it now. Turn the water and power back on. Run a cycle with the dishwasher empty and check for leaks at the sink drain, the water supply valve and at the dishwasher. Move the dishwasher back into place, if necessary, once you’re sure there are no leaks.
Let Lowe’s Help With Your Plumbing Repairs
Replacing a dishwasher hose can solve problems with foul odors and leaks. While it only requires you to make a couple of connections to the drain and to your dishwasher, preparing for the work is critical. You need to follow local codes and you need to turn off the water and power to the appliance. In some cases, you might need to install an air gap or move your dishwasher. Shop Lowes.com for your hose and air gap and find other appliance repair parts as well. Or stop by your local Lowe’s and talk to a Red Vest associate about your project. They can help you find everything you need to do the project the right way.