Without fail, water should come out of a faucet in your home when you open the tap. When no faucets work, the issues is usually with the water supply or a broken main. If only one faucet isn't working, then the problem is localized and a repair is necessary. The following are five common reasons why a single faucet may fail.
1. Blocked Aerator
The aerator screen sits just behind the faucet cap where the water comes out. If sediment or hard mineral buildup blocks this screen, water can slow to a trickle or simply not come out at all. Fortunately, this is an easy fix. Screw off the tip of the faucet and replace the screen with a new one. Alternatively, you can clean the screen by soaking it overnight in vinegar to loosen any buildup, and then brushing it off with a stiff brush before reinstalling it.
2. Water Heater Failure
If only the hot water tap isn't working, then the issue is most likely with your hot water supply. The hot water valve to the sink could be turned off, or there could be a leak in the line. Often, the issue is with the hot water itself. A failed pressure regulator, for example, may make it impossible for the hot water to effectively travel to the faucets furthest from the tank.
3. Closed Valve
Check the water valves for the affected faucet. These are usually located beneath the sink in a cabinet, although in the bathroom they sometimes sit behind the toilet or tub. Verify that both valves are turned to the completely open location. Sometimes these valves get closed by accident, usually when cleaning. Opening them will restore water flow to the faucet and any other affected plumbing in the room.
4. Water Line Leak
A more severe problem is if the water line that serves the affected faucet has sprung a leak. In this case, there is water leaking into your walls, likely in a location where the damage won't be immediately apparent. This means mold and rotting wood or drywall is going to become a problem if you don't act quickly. A leaking line must be found and repaired by a plumber.
5. Frozen Pipes
If it's below freezing outside, the cause of the failure could be frozen pipes. This is especially true in rooms that back up against the exterior of the home, since they are more exposed to the outside cold. If you suspect frozen pipes, open the tap to relieve pressure, then open any cabinet doors so air can circulate around the pipes. Call a plumber for more help.
Contact a plumbing contractor for more help with the malfunctioning faucet.