I spotted a pretty common issue this morning—one that flies under the radar until it becomes a bigger problem. Under a bathroom sink, the cold water shutoff valve was leaking right at the stem. You can see the buildup and corrosion in the photo. It’s subtle, but it’s enough to cause water damage over time, especially in a cabinet with limited airflow.

Most people wouldn’t even notice this unless they happened to pull everything out from under the sink. And that’s part of the problem—these kinds of slow leaks can go unnoticed for months. The result? Swollen cabinets, mold, and in some cases, damage to the subfloor.

These valves are called “angle stops,” and they control water to the faucet. Over time, the internal seals wear out or the packing nut loosens up. Sometimes you can tighten that nut just a bit and stop the leak—but if there’s corrosion like this, replacement is the better move.

Why It Matters for Insurance and Inspections

If you’re selling your home in Florida—or just trying to keep your insurance coverage—this can show up on a 4-point inspection. Active leaks, even small ones, are red flags for underwriters. I’ve seen policies denied or held up until things like this are repaired. It’s one of those minor issues that can turn into a major roadblock if ignored.

What You Should Do

• Inspect under your sinks occasionally—especially if it’s been a few years since the valves were touched.
• Look for corrosion or mineral buildup. That’s usually the first sign.
• Test the valve by feeling around the stem when the water’s on—just be careful not to disturb anything if you’re not sure what you’re doing.
• Call a plumber if you see anything suspicious. A simple valve swap can prevent a much more expensive repair down the road.

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Want to stay ahead of issues like this? These little things are exactly what I’m looking for during a 4-point or home inspection. If you’re in Florida and need a pro to take a look, I’m here for it.