Plumbing answer · National guidance
Reviewed and updated September 25, 2026
First separate continuous running from a short refill when nobody has used the toilet. Korky describes one explanation for the second pattern in gravity-tank toilets: water escapes past the flapper, and the fill valve replenishes it. The part you hear can be responding to the loss rather than causing it. Sound alone does not tell you which part to replace.
Check the situation from a safe position before doing anything else. Water outside the fixture, a rising bowl or a leaking or stuck control takes priority over an internal-leak check. For contained but persistent running, arrange a model-matched plumbing assessment. Report the pattern and recent work; do not buy a fill valve or a complete toilet solely because it makes a refill noise.
Report continuous flow separately from brief refills. Korky’s weak-flush guidance notes that tank fill level and fill-control behavior can be relevant to a running toilet; this is not a universal adjustment instruction.
Notice next: Describe any overflow-tube flow you already saw safely. Do not open unfamiliar equipment or change settings to test a theory.
The gravity-tank flapper example explains why a working fill valve may restart. It does not prove that every intermittent sound comes from a flapper leak.
Notice next: Note whether the sound stops, when it was first noticed, and whether water is visible outside the fixture.
The model and installed part are useful records for checking compatibility and installation. The timing does not establish that the installer made an error.
Notice next: Keep the invoice, part packaging or existing model record; ask the installer how the match and operation were checked.
Do not treat outside water as harmless just because intermittent refilling is also happening. Describe the two observations separately.
Notice next: Stop testing and contact a plumber or property emergency contact; report where water first appeared without handling leaking controls.
EPA describes a dye screen for tank-to-bowl leakage. Color reaching the bowl supports that path, not a specific replacement or a measured loss. No color during one observation does not establish that every intermittent or external leak is absent.
Notice next: Keep the result and test conditions. Use only compatible EPA/manufacturer instructions, including their staining precaution; never flush a rising or overflowing bowl to finish a test.
A short history is more useful than naming an unconfirmed failed part.
Do not recreate a fault, remove components or open a pressure vessel to collect this information.
Not necessarily. In Korky’s flapper-leak example, the valve is replenishing lost tank water. Ask what inspection establishes the actual cause instead of selecting the audible part automatically.
Yes, on a compatible accessible tank the EPA check addresses a specific tank-to-bowl path. Follow the applicable instructions and staining precaution. Skip it if access is unsafe, the system is sealed or unfamiliar, or the bowl is backing up. This page is not a universal test recipe.
Flushmate describes a compressed-air system designed for a compatible toilet. Conventional gravity-flapper guidance does not transfer to its sealed vessel. Use the actual model’s support route without opening it.
Neither proves that an intermittent issue has disappeared or that outside moisture is unrelated. Report the conditions under which you observed it and ask how the proposed correction will be verified.
Ask what was found, which part or leak path it implicates, whether the replacement matches the toilet, what the visit includes, and how changed behavior will be checked. A phone conversation can arrange that assessment; it cannot inspect the toilet remotely.
General observations and manufacturer examples are not a diagnosis of this toilet.
Utility ownership, permits, trade licensing, rental responsibility, codes, prices and provider availability must be checked for the exact property.
A city or ZIP selection does not confirm a plumber’s coverage or acceptance of the job.
This answer cannot inspect a toilet or identify a failed component from a sound.
No water-loss volume, bill saving, price, warranty outcome or provider availability is estimated.
Gravity-tank examples do not establish the design of an unfamiliar or pressure-assisted toilet.
A dye observation addresses a particular path under its observation conditions, not all leak possibilities.
Confirm responsibility, access and the proposed work for the actual property.