To turn off the bathroom water valve, first locate the shut-off valve, typically found beneath the sink or adjacent to the toilet. Turn the handle counterclockwise until it stops, ensuring no water flows. For valves with a lever, push it perpendicular to the pipe. Verify the water stops by checking the sink or toilet fill. If the valve is stuck, use a wrench to loosen it.

The importance of knowing how to shut off the valve lies in preventing water damage. According to the Insurance Institute for Property Loss Reduction (IPLR), water damage accounts for over $5 billion in annual claims in the U.S., with 15% of home insurance claims stemming from plumbing failures. Proper valve operation reduces risks of leaks, mold, and structural damage. Data from the Environmental Protection Agency (EPA) shows that a single undetected drip can waste 500 gallons of water annually, highlighting the need for regular maintenance. Additionally, the American Water Works Association reports that 98% of water-related emergencies in bathrooms are preventable with proper valve management. Turning off the valve during repairs or emergencies mitigates hazards, protecting both property and health. Neglecting this step increases vulnerability to costly repairs, as 20% of U.S. homeowners experience water damage from plumbing issues each year, averaging $7,500 per incident (IPLR, 2022). Always test the valve periodically to ensure it functions smoothly, safeguarding against unexpected failures.