water is leaking out from the bottom of my supreme plus, right onto the counter, mostly during the brew.

Diagnosis

The Keurig K-Supreme Plus utilizes a pressurized pump system that pushes water from the reservoir through a series of internal silicone hoses and plastic connectors. When water leaks specifically during the brew cycle, it indicates a failure under pressure. The most common culprit is a compromised seal at the reservoir base or a hairline crack in the internal water line that only opens when the pump creates maximum head pressure. If the leak is a slow drip, it is likely a seating issue where the reservoir valve isn't fully engaging the intake port. However, if the leak is a steady stream or "puddling" during the actual extraction process, the internal O-ring has likely perished, or a connector has slipped. You can confirm the source by drying the machine completely, placing a piece of dry paper towel under the base, and running a "water-only" brew; the location of the first wet spot on the towel will tell you if the leak is centered (valve failure) or offset (internal hose failure).

How to Fix It

Follow these steps to isolate and resolve the most common leakage points:

1. Inspect the Reservoir Valve: Lift the water reservoir completely off the machine. Look at the bottom of the tank where the plastic valve is located. Check the black rubber O-ring for any nicks, tears, or "flattening." If the ring looks stretched or cracked, it must be replaced to maintain a vacuum seal.
2. Clean the Intake Port: Use a damp microfiber cloth to wipe the receiving port on the machine (the hole where the reservoir sits). Even a small amount of calcium buildup or a stray coffee ground can prevent the valve from seating flush, allowing water to spray outward under pressure.
3. Verify the Reservoir Seat: Place the reservoir back on the machine. Instead of just dropping it in, apply firm downward pressure until you feel the valve click into the locked position. Ensure the tank is perfectly vertical; if it is tilted even slightly, the seal will fail during the high-pressure brew phase.
4. Clear the Needle: If the leak is actually spraying from the top and running down the inside of the chassis to the bottom, the exit needle may be clogged. Use a straightened paperclip to gently clear the needle in the K-Cup holder to ensure water isn't backing up and forcing its way out of the internal seals.

If That Didn't Work

• Internal Hose Re-seating: If you are comfortable opening the chassis, remove the bottom screws and lift the base. Look for the silicone tubing connecting the pump to the brew head. Over time, the vibration of the pump can cause these tubes to slip off their plastic barbs. Push the tubing firmly back onto the barb and secure it with a small zip-tie or a replacement hose clamp.
• Pump Gasket Replacement: The pump assembly on the K-Supreme Plus has a primary gasket that can fail. If you see water pooling specifically around the pump motor, the gasket has failed. You will need to replace the pump assembly entirely, as the internal seals on these units are not serviced individually.
• Crack Detection: Inspect the plastic water lines for "stress whitening"—areas where the plastic looks white or cloudy. This is a sign of a hairline crack. If a crack is found, a temporary fix is food-grade silicone sealant, but the permanent solution is replacing the internal plumbing line.
• Descale the System: Heavy mineral buildup can create "back pressure," forcing water out of the weakest seal. Run a full descaling cycle using a white vinegar solution or a commercial descaler to ensure the water path is completely clear.

Heads Up

• Avoid Overfilling: Never fill the reservoir past the "Max" line; overfilling can put undue pressure on the valve seal and lead to premature leaks.
• Use Filtered Water: To prevent the calcium buildup that causes valve malfunctions, use filtered or bottled water rather than hard tap water.
• Power Warning: Always unplug the machine from the wall outlet before attempting to inspect the internal hoses or opening the chassis to avoid electrical shock.
• Dry the Base: If a leak occurs, do not simply wipe the counter. Use a vacuum or cloth to ensure the bottom vents of the machine are dry so that moisture isn't sucked back into the electronics during the next heat cycle.