Urinal Keeps Running? How to Troubleshoot a Flushometer
A running urinal usually points to debris, worn diaphragm or piston parts, a blocked metering passage, wrong repair parts, or a control-stop problem.
Last reviewed 2026-09-12 · General facility-maintenance information, not a substitute for site procedures, manufacturer instructions, codes, or qualified professional judgment.
Quick answer
Safety boundary
Likely causes
- Blocked metering bypass
- Debris under sealing surfaces
- Worn diaphragm or piston assembly
- Incorrect flush-volume kit
- Control-stop issue
Symptom → cause → first move
Blocked metering bypass
Check: Identify brand, model, and flush volume
First move: Clean serviceable internal parts
Debris under sealing surfaces
Check: Close the control stop
First move: Replace the correct urinal-specific repair kit
Worn diaphragm or piston assembly
Check: Relieve pressure before opening the valve
First move: Restore water slowly and test several flushes
Incorrect flush-volume kit
Check: Inspect internal parts for grit and damage
First move: Clean serviceable internal parts
Control-stop issue
Check: Verify the repair kit is for a urinal
First move: Replace the correct urinal-specific repair kit
What to check first
Bring these
- Flashlight
- Rags or towels
- Basic hand tools appropriate to the fixture
- Correct manufacturer repair parts when needed
Before touching anything
- Confirm the exact location and complaint.
- Photograph labels, settings, fault codes, and the original condition.
- Determine whether the failure affects one item or several nearby items.
- Know how to safely isolate the system if the task requires it.
Step-by-step procedure
- 1Identify the valve and flush volumeIdentify valve series, fixture requirements, and specified flush volume before choosing an internal kit; a toilet diaphragm is not interchangeable by appearance.
- 2Isolate water and release pressureClose the identified control stop gently, operate the valve to release pressure, and confirm isolation before removing the cover.
- 3Inspect the correct internal assemblyFollow the exact service drawing to inspect the diaphragm or piston, sealing surfaces, and relief components for grit or damage.
- 4Clean without changing meteringClean only as the manual permits and never enlarge the metering bypass; replace damaged parts with the exact compatible assembly.
- 5Reassemble and verify shutoffReassemble and restore the stop gradually to the prescribed flow. Verify several complete flushes, positive shutoff, no splash, and dry joints before reopening.
Routine fixes that make sense here
- Clean serviceable internal parts
- Replace the correct urinal-specific repair kit
- Restore water slowly and test several flushes
Urinal-specific note
Urinal flushometers often look almost identical to water-closet valves, but the metered volume is different. A wrong-volume internal kit can create long flushes, weak performance, or continuous run-on. Treat the existing valve markings as the starting point for parts identification.
Stop and call a licensed professional when
- Control stop will not close
- Valve body is cracked
- Supply pressure is abnormal across several fixtures
Common mistakes
- Replacing parts before proving the failure.
- Changing several settings or components at once.
- Failing to photograph the original condition.
- Ignoring whether nearby equipment has the same symptom.
- Crossing into electrical, refrigerant, life-safety, structural, or plumbing work beyond training.
FAQ
What should I check first?
Start by deciding whether the problem is local to one fixture or piece of equipment. Then begin with the simplest safe observation: identify brand, model, and flush volume.
What is the most common mistake?
Replacing parts before proving the failure. BuildingWrench recommends documenting the symptom, changing one thing at a time, and testing after each change.
When should maintenance stop?
Stop when the repair crosses your training or site-safety boundary. In this case, one clear handoff point is: control stop will not close.
What should I document?
Record the exact location, model or asset tag, what the equipment was doing, what you checked, what you changed, and whether the fix held through repeated testing.
Parts for this repair
Sloan 1.0 GPF urinal diaphragm
Repair part for compatible Sloan urinal flushometers; verify model and GPF.
Check on AmazonSloan flushometer rebuild kit
Repair kit for compatible Sloan flushometers; verify model and GPF.
Check on AmazonAffiliate links — BuildingWrench may earn a commission at no extra cost to you. Verify model, size, rating, and compatibility before ordering.