To fix a leaking shower valve with separate hot and cold water, first shut off the water supply by closing the valves beneath the sink. Remove the escutcheon plate covering the valve stem using a screwdriver. Disassemble the stem by unscrewing it counterclockwise with a pipe wrench. Inspect the seat inside the valve body for damage or debris. Replace worn O-rings, seals, or the entire stem if necessary. Apply silicone lubricant to the stem and threads before reassembling. Turn the water back on and test for leaks. Repeat the process if the leak persists.

This method addresses common failure points such as degraded seals, loose components, or misaligned seats. According to the Environmental Protection Agency (EPA), 55% of household leaks stem from fixtures like faucets and shower valves, costing homeowners an average of $270 annually in water waste. Replacing O-rings and stems, typically costing $10–$30, prevents further damage, as corrosion or mineral buildup can destroy the valve seat, requiring costly professional repair. A 2021 study by the American Water Works Association found that 68% of leaks in older plumbing systems are due to worn valve components, emphasizing proactive maintenance. By disassembling the valve, homeowners can identify and replace specific parts, avoiding unnecessary full valve replacement. Regular inspection every 6–12 months extends fixture lifespan and reduces water waste, aligning with EPA WaterSense guidelines.