If your toilet flushes but the tank never refills — or refills very slowly — it can leave the toilet unusable. This is a common problem and is usually caused by an issue with the toilet’s water supply or fill mechanism, not a clog in the drain.
In most cases, the fix is simple and doesn’t require replacing the toilet.
Quick Answer:
A toilet usually won’t refill after flushing because the fill valve isn’t opening properly, the water supply valve is partially closed, debris is blocking the fill valve, or the float is stuck in the down position. Adjusting or cleaning the fill valve often restores normal refilling.
Why This Happens
After you flush, the toilet relies on the fill valve to open and allow fresh water into the tank. If that process is interrupted, the tank stays empty or refills too slowly to be usable.
Common causes include:
- The toilet supply valve being partially closed
- A stuck or misadjusted float
- Debris inside the fill valve
- A kinked or restricted supply line
- Wear inside the fill valve mechanism
These issues can appear suddenly, even if the toilet worked normally before.
Step-by-Step: How to Fix a Toilet That Won’t Refill
Step 1: Check the Toilet Supply Valve
Look at the shutoff valve located behind or below the toilet.
- Turn it fully counterclockwise
- Do not assume it’s open just because it looks aligned
A partially closed valve is one of the most common causes of refill problems.
Step 2: Lift the Float Manually
Remove the tank lid and locate the float.
- Gently lift the float upward
- Listen for water entering the tank
If water starts flowing when you lift the float, the fill valve is likely misadjusted or sticking.
This is closely related to issues that cause a toilet to keep running, and the same parts are often involved.
Step 3: Check for Debris in the Fill Valve
Sediment or mineral debris can block the fill valve and stop water from entering the tank.
To check:
- Turn off the toilet supply valve
- Flush to empty the tank
- Remove the top cap of the fill valve (design varies)
- Rinse away debris and reassemble
Many refill problems are resolved at this step.
Step 4: Inspect the Supply Line
Make sure the flexible supply line:
- Isn’t kinked
- Isn’t crushed behind the toilet
- Isn’t leaking
If water flow to the fill valve is restricted, the tank won’t refill properly.
Step 5: Test and Adjust
Turn the supply valve back on and flush the toilet.
Watch the refill process and confirm:
- Water flows smoothly
- The tank refills to the correct level
- The fill valve shuts off automatically
If refilling is extremely slow, the issue may overlap with a toilet filling slowly, which has slightly different causes.
What Not to Do
- Don’t keep flushing repeatedly
- Don’t force internal parts
- Don’t ignore a silent or dry tank
- Don’t pour cleaning chemicals into the tank
Repeated flushing without refilling can damage internal components.
When to Call a Professional
Call a plumber if:
- The tank won’t refill after cleaning the fill valve
- Water leaks from the valve or supply line
- Multiple toilets won’t refill
- You suspect a pressure or supply issue
If more than one toilet is affected, the issue may be related to a broader plumbing problem.
Safety Notes
- Turn off the toilet supply valve before disassembly
- Handle plastic parts carefully to avoid cracking
- Keep towels nearby in case of spills
- Replace the tank lid gently to avoid damage
Common Homeowner Questions
Why does my toilet flush but not refill at all?
The fill valve may be blocked, stuck, or not receiving enough water.
Can a bad fill valve stop refilling completely?
Yes. Worn or clogged fill valves are one of the most common causes.
Is replacing the fill valve difficult?
Most replacements are straightforward and can be done with basic tools.