Start with what changed after the repair
Think back to the original symptom. Did the toilet run continuously, or briefly refill every so often? Is that pattern exactly the same now? Write down the replacement part and whether you changed the chain setting or another component at the same time. Those details are more useful than buying a second part without knowing what failed.
A new part still needs to suit the fixture
Flappers differ in size and design. A package marked universal is not a reason to ignore the toilet manufacturer’s compatibility instructions. A provider can compare the installed part with the tank model and check whether the flapper sits evenly on its sealing surface. Keep the packaging or part number if you have it.
Look for a chain that holds the flapper open
With the lid safely set on a stable surface, observe whether the handle returns normally and the chain catches on anything. A chain under tension can keep the flapper from closing. Do not bend parts or guess at an adjustment. Use the instructions for the actual fixture, or ask the provider to check the installation.
Separate a seal problem from a filling problem
Note whether water continues entering the overflow tube, or whether the tank stops filling and later starts again. These are useful observations, not a complete diagnosis. The flush-valve seat, flapper fit, refill arrangement and fill-valve shutoff may need separate checks. Replacing parts in sequence can miss the underlying fault.
Helpful product reference · optional DIY considerations
Parts and tools worth checking
These products are examples to compare after identifying the problem. Not every toilet needs a new part, and a product listing is not a diagnosis or substitute for a suitable professional.
Affiliate disclosure: The links below are paid Amazon links. We may earn a commission from qualifying purchases at no additional cost to you.
Replacement flapper
Korky Standard 2-Inch Ultra High Performance Flapper
A replacement part to consider only if the installed flapper size and the toilet model match. A new flapper cannot fix every running-toilet problem.
Check two-inch versus three-inch flush valve size and tank-model compatibility.
See on Amazon ↗
Fill valve
Fluidmaster 400H Universal Toilet Fill Valve
A separate fill-valve option if diagnosis points to water continuing to enter or refill the tank rather than leaking past the flapper.
Confirm tank clearance and the installed valve requirements before ordering.
See on Amazon ↗
Complete repair kit
Fluidmaster 400AKRP10 Complete Toilet Repair Kit
A multi-part option for compatible toilets when inspection finds several worn tank components.
Not necessary when a single component or adjustment addresses the fault.
See on Amazon ↗Illustrations are original diagrams, not Amazon product photos. Check current product details and compatibility on Amazon and with the fixture manufacturer. Fix Up Bath remains an independent referral service.
What to tell the person you call
Explain that the problem persisted after a flapper replacement. Share the toilet model if readable, the new part number and a short description of when the sound returns. Mention any water outside the fixture. Ask the provider to diagnose the remaining problem before discussing additional work. For broader symptoms, see our running toilet repair page.
Questions homeowners ask
Should I buy another flapper immediately?
First confirm compatibility and the source of the continued running. Another replacement may not address a fill-valve or sealing-surface problem.
Does continued running mean the new flapper is defective?
Not necessarily. Fit, installation and other tank components need to be considered.
Should I keep the old and new part details?
Yes. A photo of the packaging and the toilet model can help a provider understand what has already been tried.
Can I leave the toilet running while I wait?
Avoid leaving uncontrolled water loss unattended. If the fixture valve works and you can reach it safely, isolate the toilet. Do not force a stuck valve.
Does this mean the whole toilet must be replaced?
A failed first repair does not establish that. Ask for the fault to be identified before discussing fixture replacement.
Manufacturer and consumer resources
Use instructions for your actual fixture and valve model. These resources provide additional context.
General homeowner information, not a diagnosis of your fixture. Photos are illustrative scenes, not providers available through this website.
