How to Replace a Toilet Fill Valve (Simple DIY Fix)
- The Best Life Awaits
- 2 days ago
- 2 min read
Updated: 1 day ago
Continuing our recent toilet repairs, it was time to replace the fill valve.
If you’re still troubleshooting your toilet, start with our post on replacing the canister gasket.
That guide walks through how to diagnose common toilet issues and determine which part has failed before you start swapping components.
In our case, the diagnosis was straightforward.
The canister had already been replaced recently, so we knew that wasn’t the issue.
That left two possible culprits:
The fill valve
The float
On our model, those are integrated into one assembly.
How We Knew the Fill Valve Was Failing
To adjust the water level on this toilet, you press down on the fill valve and rotate it to raise or lower the float.
We adjusted it several times.
Each time, the water level continued rising until it overflowed into the overflow tube.
That’s a classic sign the fill valve is no longer regulating pressure correctly.
At that point, replacement is faster and more reliable than trying to “tune” it.
And yes — it often feels like parts fail in sequence.
Fix one issue, and the next weakest component gives out.
That’s homeownership.
(Our TOTO Washlet had also recently failed. Apparently it was toilet month.)
Tools You May Need
This repair is beginner-friendly.
Possible tools:
Adjustable wrench (for supply line nuts)
Screwdriver (for adjustments)
Utility knife (if replacing supply line)
Bucket (to catch water)
Towels or rags
In our case, everything was hand-tight. We only needed:
Knife
Bucket
Rags
Step-by-Step: Replacing the Fill Valve
Turn off the water supply to the toilet (valve at the wall).
Flush the toilet to drain most of the tank.
Place a bucket under the tank, beneath the fill valve connection.
Disconnect the water supply line from the fill valve.
Remove the nut securing the fill valve to the bottom of the tank.
Disconnect the small refill tube from the overflow pipe.
Remove the old fill valve and catch any remaining water.
Insert the new fill valve.
Reattach the securing nut (hand-tight, then slight snug).
Reconnect the supply line.
Turn water back on and adjust water level as needed.
That’s it.
Total time: about 20–30 minutes.
When to Replace Instead of Adjust
Replace the fill valve if:
Water continuously runs into the overflow tube
The tank never stops filling
Adjustments don’t stabilize the water level
The valve is more than 5–7 years old
Fill valves are inexpensive and considered wear items.
Final Thoughts
Toilet repairs look intimidating — but most internal tank components are modular and designed for easy replacement.
If you’ve already replaced a flapper or canister gasket, this is the natural next step in troubleshooting.
And once you’ve done it once, it becomes a 15-minute job the next time.
Homeownership isn’t about avoiding failures.
It’s about knowing how to fix them when they happen.
We'll go over these steps in more detail in this video.
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