Before repairing a water closet, the first step is to

• A. Drain the line
• B. Disconnect supply
• C. Turn off the water
• D. Call a plumber

Answer: (C)

Shutting off the water to the toilet is the first step because it immediately stops the flow of water, preventing a flood or extra water damage while you work. Locate the shut‑off valve on the supply line behind the toilet and turn it clockwise to close. If you can’t find it or it won’t shut off, use the main house valve to stop all water. Once the water is off, you can drain what’s left in the tank and bowl and safely proceed with the repair. The other steps would come after you’ve stopped the water, and calling a plumber is only necessary if the shutoff can’t be controlled or the problem is more complex.