A leaky Sub-Zero refrigerator can be a surprise, given the brand’s superior construction and performance. Fortunately, most leaks are quickly identified with a straightforward cause. Why is my Sub-Zero refrigerator leaking water? The water line may be loose or improperly connected. Use these DIY tips to find the source of the leak and the right solution.
Sub-Zero Refrigerator Leaking Water?
Here Are 5 Common Causes
The most likely causes for a Sub-Zero refrigerator leaking water include simple fixes. From changing the water filter to defrosting the drain tube, here’s how to stop the leak and restore your Sub-Zero’s function.
1. Refrigerator Water Line Leaking
If you find your Sub-Zero refrigerator leaking water underneath it may be due to a water line issue. This thin plastic tube delivers water from your home supply to the refrigerator. To access the water line, turn the water supply valve off and unscrew the bottom kickplate.
The following issues can result in a leaky water line:
- Loose connection: Tighten any loose connections and make sure the water line is properly connected to the refrigerator and your home water supply.
- Faulty connection: Cracks or other damage can cause leaking at the water line’s connection points. In this case, they require professional replacement.
- Damage: Check the water line for cracks or holes that can cause leaks. A damaged water line must be professionally replaced.
2. Leaking From Water Filter
Is your Sub-Zero water dispenser dripping? These leaks often result from a water filter malfunction.
The following problems can cause water filter leaks:
- Clogged filter: Over time, the water filter can become clogged from the minerals and impurities it screens out . This can cause leaks at the dispenser or in the filter manifold. You may also notice your refrigerator ice maker not working properly if a clogged filter restricts its water supply. Sub-Zero recommends changing the filter on an annual basis to prevent clogs and leaks.
- Filter incorrectly installed: Incorrect installation can cause filter head leaks that accumulate inside the refrigerator. Refer to your user manual to make sure the filter is installed correctly. Always use an OEM filter to ensure that it fits and operates properly.
- Damaged filter: Damaged O-ring gaskets or a cracked filter cartridge can also cause leaks in the filter manifold. If the filter shows visible damage, it must be replaced.

3. Defective Water Inlet Valve
If your Sub-Zero refrigerator leaks water from the top, it’s possible that the water inlet valve is defective. This valve opens and closes to provide the refrigerator with water from your home supply and is located behind the top grille. If the valve is leaking, turn off the refrigerator’s water supply until it can be professionally replaced.
4. Frost Buildup Inside Refrigerator
Water inside Sub-Zero refrigerator is often due to a buildup of frost.There are several possible issues that cause frost to accumulate.
Here’s why frost can develop inside the refrigerator and cause leaks:
- Doors aren’t properly closed: Even a small door opening can cause frost to develop inside the refrigerator or freezer and cause leaks. Make sure the doors are properly closed and free of obstructions after each use.
- Damaged door gasket: A loose or cracked door gasket can allow warm air to enter the refrigerator and cause leaks from frost development. If the gasket is loose or damaged, it must be replaced.
- Incorrect temperature settings: Make sure the refrigerator and freezer are set at the right temperature to deter the development of frost. Sub-Zero recommends setting the refrigerator at or near 38℉ and the freezer at approximately 0℉.
- Clogged drain tube: Condensation in Sub-Zero refrigerator crisper drawers or frost buildup behind the drawer assembly is often due to a clogged drain tube. Depending on your model refrigerator, you can unclog the drain tube with a solution of warm water, bleach and dish detergent. To access the tube, remove the bottom kick plate and flush the drain trough with the solution via a turkey baster. Once the clog is dispelled, it may be necessary to manually defrost the refrigerator to remove the frost.

5. Drain Pan Leaking
A Sub-Zero drain pan is found underneath the refrigerator behind the front kick plate. This pan collects any remaining water from the automatic defrost system so it can eventually evaporate. If you find your Sub-Zero drip tray overflowing, make sure it’s properly installed and level. Cracks or holes in the pan can also cause leaks. If the pan appears damaged, it must be replaced by a professional Sub-Zero repair service.
The technicians at Apex Appliance Service can fix a Sub-Zero refrigerator leaking water regardless of the cause. Call us to schedule your expert service today.