One shut-off valve only!
A plumbing fixture is only supposed to have one shut off valve for each hot and cold water supply pipe. If the plumbing fixture only has one cold or hot water supply connection, there should only be one shut off valve for the plumbing fixture.
Dual shut offs are no good
Having dual shut off valves for a faucet can create water flow issues especially if the older ones are clogged up with sediment. Referring to the picture below it shows a total of four shut-off valves. The bottom set of shut-offs are the original ones installed for the sink. Apparently, someone replaced the kitchen faucet but didn’t want to change the older shut offs, so they thought by installing a newer set above the older ones would be okay.
Only one set of shut- off valves
Here is a valve replacement job I just did for the kitchen sink I mentioned above. There is one valve on the hot water supply pipe and cold water supply pipe.
Do you have this problem?
If your not sure that your plumbing fixtures may be double-valved, click here to schedule a shut-off valve replacement with Vince, a Pittsburgh plumber who you can trust to do the job right!