Check each toilet for a silent tank leak
A worn tank seal can send clean water into the bowl continuously without an obvious puddle.
When it usually needs attention
Usually repeats every 1 year
EPA WaterSense recommends checking tank toilets for silent leaks at least once a year.
When this guide applies
Only applies when a conventional tank-type toilet is confirmed; flushometer and specialty fixtures need their own route.
What to do
Follow the WaterSense dye test for a tank-type toilet, wait the directed time without flushing, check for color in the bowl, then flush immediately.
Applies when: Only applies when a conventional tank-type toilet is confirmed; flushometer and specialty fixtures need their own route.
Who should handle it: A resident may perform the non-invasive test; repair responsibility belongs to the responsible owner or manager unless the resident is authorized to repair it.
Tools
- Timer
Parts and supplies
- A few drops of food coloring or a toilet dye tablet
Safety gear
- Wash hands after contact with the toilet area
Before you start
- Confirm a conventional tank toilet
- Do not use the toilet during the test
Power, water, or fuel shutoffs
- Know the toilet supply valve before testing, but do not force a stuck valve
Cleaner or chemical limits
No cleaner is used; flush after the test to prevent staining.
Stop and get help when
- Stop for a cracked fixture, active overflow, sewage backup, loose toilet, or a stuck/corroded valve
Who to call: Use the responsible owner or a qualified plumber for leaks or unsafe fixture conditions outside an authorized simple repair.
Reviewed sources
- Home MaintenanceEPA WaterSense · reviewed July 13, 2026