To fix a toilet water shut-off problem, first locate the shut-off valve, typically behind the toilet or near the wall. Turn it clockwise to shut off the water. Remove the tank lid and inspect the fill valve, float mechanism, and ball or flapper. If the float is stuck or misadjusted, adjust it to ensure the water level stops at the proper mark. Replace a damaged ball or flapper. If the fill valve is leaking, replace it. Finally, test the toilet by flushing and checking for leaks.

This process addresses common causes such as loose valves, faulty floats, or clogged lines. According to the Environmental Protection Agency (EPA), 60% of household water leaks originate from faulty valves, pipes, or fixtures, often leading to significant water waste. For example, a running toilet can waste over 200 gallons of water daily, equivalent to 7,300 gallons annually per household. Adjusting the float mechanism to prevent overfilling reduces water usage and potential overflow damage. The EPA estimates that proper maintenance of water valves and shut-off systems can prevent up to 30% of water-related property damage annually. Additionally, replacing worn components like flappers and fill valves costs less than $20 on average, compared to $200+ for water damage repairs. Data from the American Water Works Association (AWWA) shows that 1 in 50 households waste 10,000 gallons yearly due to undetected leaks, underscoring the importance of timely shut-off valve inspections and repairs. Consistent maintenance ensures efficient water use, minimizes utility bills, and avoids costly repairs.