[stomachmonkey]

It's 8 years old.

House was a new build.

It's not apart, that was a stock photo. After you pull the handle off there is a decorative cap with integral nut on the top. The calcification is on the underside / threads of the cap. It's soft metal and there is no where to grab the cap (other than the nut normally hidden by the handle) to loosen it without destroying the finish.

Cap is on there so securely that the entire unit, base and all started turning. Garbage disposal in front of the fixture underneath so no room to hold it from below without removing disposal. Not going through all that trouble. Have I mentioned how much I hate working upside down in cramped spaces?

After thinking about it I realized why it does not leak.

I had assumed the check ball cut off flow from the lines when in fact it just shuts off flow to the spigot. The internal pressure from the line side pushes / forces the check ball against the spigot side seal.

It actually needs the pressure to seal.