A toilet supply line usually leaks because a hose, washer, coupling, valve or fill-valve seal is loose, worn, damaged, corroded or misaligned. Limit the leak by closing the toilet isolation valve only if it is accessible and turns easily. Keep the water off and call a licensed plumber if any component needs repair or replacement.
Find the source
Dry the accessible hose and fittings, then use dry tissue to identify the first wet point without dismantling anything. If checking requires the water to be reopened, leave that test to a plumber.
- Hose coupling: Water at either connection may indicate a loose coupling, failed washer, damaged thread or misaligned fitting.
- Hose body: Moisture, bulging, corrosion, splitting, brittleness or kinking means the hose is damaged.
- Isolation valve: Water around the spindle, valve body or wall connection points to a valve or fixed-pipe leak.
- Under the cistern: Water running from above the coupling may come from the fill-valve shank or seal.
Check the highest wet point because water can run down the hose before dripping. Broader toilet leak tracing may be needed if the first wet area is not the true source.
Stop the leak safely
- Turn the isolation valve gently clockwise if it moves freely. Never force a seized, damaged or leaking valve.
- If water continues flowing, use the correct procedure to turn off the mains water only if the valve is known, safely accessible and easy to operate.
- Place towels or a container beneath clean water and keep it away from electrical fittings. Keep clear and seek urgent help if water may contact electricity.
- Look for cracks, corrosion, damaged threads, distortion or a coupling that is not sitting squarely, but do not dismantle any fitting.
- Do not tighten, reseat or improvise a repair. Do not apply sealant or thread tape, dismantle the isolation valve, or disturb fixed pipework.
After a licensed repair, the plumber should restore the supply slowly and test each joint and the toilet through its operating cycle.
When to call a licensed plumber
Arrange a licensed plumber if the valve will not isolate the water, the leak persists, or any hose, washer, valve, fill-valve seal, thread or fitting is damaged. Keep the supply off where possible, especially if water is spreading into walls, flooring or cabinetry. Contact our leaking-toilet repair team to identify the failed component and complete the required plumbing work.