A high loop in the dishwasher’s drain line is a simple but essential feature that prevents dirty water from flowing back into the dishwasher during operation. If the high loop is missing, it can lead to backflow issues, resulting in dirty water contamination and poor dishwasher performance. Here’s how to address this problem effectively.
What is a High Loop?
A high loop is when the dishwasher’s drain hose is routed upward before connecting to the sink drain or garbage disposal. This upward loop prevents wastewater from the sink or drain from flowing back into the dishwasher.
Why a High Loop is Important
1. Prevents Backflow
• Stops dirty water and debris from entering the dishwasher during drainage.
2. Maintains Cleanliness
• Ensures dishes are washed with clean water, free from contaminants.
3. Prevents Odors
• Reduces the chance of stagnant water causing foul smells in the dishwasher.
4. Meets Installation Standards
• Many building codes and manufacturer guidelines require a high loop or an alternative backflow prevention method.
Signs of a Missing High Loop
1. Dirty Water in the Dishwasher
• Pooled water with debris remains at the bottom after a cycle.
2. Water Backing Into the Sink
• Water from the sink flows into the dishwasher.
3. Foul Odors
• Persistent bad smells from standing or contaminated water in the dishwasher.
4. Poor Cleaning Performance
• Dishes are not cleaned properly due to backflow contamination.
How to Install a High Loop
1. Turn Off the Dishwasher
• Unplug the dishwasher or switch off the circuit breaker to ensure safety.
2. Locate the Drain Hose
• Find the dishwasher’s drain hose, which typically runs from the back of the appliance to the sink drain or garbage disposal.
3. Create the High Loop
• Pull the drain hose upward so it forms a loop at least 20 inches above the floor or the base of the dishwasher.
4. Secure the High Loop
• Attach the drain hose to the underside of the countertop using a clamp or zip tie to hold it in place. Ensure it stays securely elevated.
5. Reconnect the Drain Hose
• Reattach the hose to the sink drain or garbage disposal, ensuring the connection is tight to prevent leaks.
6. Test the Dishwasher
• Run a short cycle and observe the drainage process to ensure water flows correctly and no backflow occurs.
Alternatives to a High Loop
1. Install an Air Gap
• An air gap is a small device mounted on the sink or countertop that prevents backflow by creating a physical barrier.
• This may be required in some regions to comply with plumbing codes.
2. Check Valve Installation
• If a high loop or air gap isn’t feasible, a check valve in the drain line can serve as a backflow prevention measure.
Preventative Maintenance Tips
1. Inspect the Drain Line Regularly
• Check for kinks, blockages, or loose connections in the drain hose.
2. Clean Filters and Drains
• Regularly clean the dishwasher filter and check for debris in the drain.
3. Ensure Proper Installation
• Confirm that the high loop or other backflow prevention measures are in place after installation or maintenance.
4. Use Dishwasher Properly
• Avoid overloading the dishwasher or using excessive detergent, which can contribute to clogs and backflow issues.
When to Call a Professional
• You’re unsure how to create or install a high loop properly.
• The dishwasher continues to experience backflow issues despite installing a high loop.
• An air gap or check valve needs to be installed, and you’re unfamiliar with the process.
• Persistent drainage or plumbing issues are affecting the dishwasher and sink.
Conclusion
A high loop is a crucial component for backflow prevention in a dishwasher. If it’s missing, installing one is a straightforward fix that ensures proper drainage, prevents contamination, and maintains the cleanliness of your dishes. For complex installations or persistent issues, consulting a professional ensures your dishwasher operates efficiently and complies with local plumbing standards. Regular maintenance and inspections can help prevent future backflow problems.