Are saddle valves bad?
Furthermore, can saddle valves be shut off?
A saddle valve is mounted directly on to a pipe which is usually 1/2 inch copper tubing. Saddle valves are self-tapping devices. Turning the handle counter-clockwise opens the valve. These valves can be installed without shutting off the main water supply.
Also to know, why do saddle valves leak?
It is saddle valve. Generally they're used to supply ice makers. It is dripping because the valve is either not closed completely, or because the valve has developed a leak. Now, shut off the house water supply.
To replace a saddle valve or tee off an existing water line, start by obtaining the needed parts. I'm assuming the saddle valve is connected to a ½” copper water line. They've proven to be reliable, but they're far more expensive than traditional copper fittings.