Stuck water valves usually occur when calcium and minerals from water build up over time and lock the valve into place. Since water valves are only turned when performing plumbing work, it can sometimes be years before a valve is turned. Freeing up a stuck valve is not difficult when the proper technique is used. To prevent valves from becoming stuck, turn them off and then back on at least once or twice per year.
Open a can of spray lubricant and spray it around the base of the water valve. Spray until the valve is completely saturated.
Allow the lubricant solution to sit on the water valve for approximately 10 to 15 minutes to dissolve the calcium and minerals.
Place a wrench around the face plate of the water valve and place your other hand on the water valve itself.
Turn the wrench one to two degrees counterclockwise until the faceplate starts to move.
Remove the wrench and turn the water valve. The valve should move freely.
Wipe away excess lubricant from the valve and surrounding area with a cloth.