Tank stays empty after one flush
You flush once, the bowl drains, and no water comes back into the tank.
Start here: Start with the wall shutoff valve and make sure the house still has water pressure at nearby fixtures.
Toilet troubleshooting
Toilet Tank Not Filling
Direct answer: When a toilet tank will not fill, the problem is usually a closed or restricted water supply, debris in the toilet fill valve, or a failed toilet fill valve.
Most likely: Start at the wall shutoff and the fill valve cap before you assume the whole toilet needs work.
First separate a no-water problem from a slow-fill problem. If the bowl flushes down and the tank stays empty, you are dealing with incoming water, not a drain issue. Reality check: most of these turn out to be a partly closed valve or a fill valve packed with grit. Common wrong move: cranking on an old shutoff valve until it starts leaking at the stem.
Don’t start with: Do not start by replacing random tank parts. A flapper usually does not cause a tank that never refills.
Tank empty after flushing?Check whether water is reaching the toilet before touching tank parts.
Tank fills very slowly?Look for a restricted shutoff, kinked toilet supply line, or debris in the toilet fill valve.
Last reviewed: 2026-04-04
What you’re seeing
Tank fills very slowly
Water trickles into the tank and it takes several minutes to refill.
Start here: Look for a partly closed shutoff valve, a kinked toilet supply line, or sediment in the toilet fill valve.
No refill sound at all
The tank is low or empty and you hear nothing from the fill valve.
Start here: Lift the tank lid and check whether the float is stuck in the up position or the fill valve is jammed shut.
Refill starts only if you jiggle something
The tank may refill if you tap the fill valve or move the float by hand.
Start here: That points strongly to a sticking toilet fill valve rather than a drain or flapper problem.
Most likely causes
1. Shutoff valve is closed or only partly open
This is common after cleaning, painting, recent plumbing work, or someone trying to stop a small toilet leak.
Quick check: Turn the toilet shutoff valve gently counterclockwise until it stops, then flush and listen for refill.
2. Toilet fill valve is clogged with grit or mineral debris
If the home had recent water work, old galvanized piping, or sediment in other fixtures, debris often lodges in the fill valve first.
Quick check: Remove the tank lid and see whether the float moves freely but little or no water enters the valve.
3. Toilet supply line is kinked or internally restricted
A bent braided line, an old rigid line, or debris at the inlet can starve the tank even when the shutoff looks open.
Quick check: Look behind the toilet for a sharp bend, flattening, or corrosion at the supply connection.
4. Toilet fill valve has failed internally
If water supply to the toilet is good and the valve still will not open or only works when tapped, the fill valve is usually done.
Quick check: With the shutoff fully open, move the float down by hand. If nothing changes, the toilet fill valve is the leading suspect.
Step-by-step fix
Step 1: Make sure the toilet is actually getting water
A toilet tank cannot refill if the supply is shut off or weak, and that is the fastest thing to rule out.
- Look at the shutoff valve on the wall or floor behind the toilet.
- Turn the shutoff valve gently counterclockwise until it stops. Do not force it.
- Check a nearby sink or tub faucet to confirm the bathroom has normal cold-water flow.
- Flush the toilet and listen for any refill sound at the tank.
- If the toilet recently stopped filling right after plumbing work, expect debris or a partly closed valve before anything else.
Next move: If the tank starts filling normally, the shutoff was closed or partly closed and you are done for now. If the tank is still empty or only trickling, move on to the tank-side checks.
What to conclude: You have separated a simple supply setting issue from a restriction or failed toilet part.
Stop if:
- The shutoff valve starts leaking around the handle or packing nut.
- The valve will not turn without heavy force.
- There is no water pressure at nearby fixtures either, which points beyond the toilet.
Step 2: Check for a stuck float or obvious fill valve hang-up
A float stuck in the up position tells the fill valve the tank is already full, so no water enters.
- Remove the tank lid and set it on a towel or safe flat surface.
- Look at the toilet fill valve on the left side of most tanks where the supply line connects underneath.
- Gently move the float down by hand and see whether water starts flowing.
- Make sure the float is not rubbing the tank wall, chain, or overflow tube.
- If the valve starts and stops only when you move or tap it, note that as a strong sign of a failing toilet fill valve.
Next move: If lowering the float starts a steady refill and it keeps working, the float was hanging up and may just need a small adjustment or repositioning. If the float moves freely but little or no water enters, the valve is likely clogged or failed.
What to conclude: This separates a simple mechanical hang-up from a supply restriction inside the toilet fill valve.
Step 3: Look for a restricted toilet supply line
A toilet can have house water pressure and still starve at the tank if the supply line is kinked or plugged.
- Inspect the toilet supply line from the shutoff valve to the bottom of the tank.
- Look for a sharp bend, crushed section, corrosion, or mineral buildup at either end.
- If the line is visibly kinked or damaged, plan to replace the toilet supply line rather than trying to straighten a damaged one.
- If you have room, lightly touch the line while someone opens the shutoff and flushes; a line that stays cold and quiet with no flow supports a restriction upstream or at the valve.
Next move: If correcting a simple bend restores normal refill, monitor it and replace the line if it has been permanently deformed. If the line looks fine and the tank still will not fill, the toilet fill valve is the next place to focus.
Step 4: Clear debris from the toilet fill valve if the supply seems good
Sediment often clogs the fill valve cap and inlet, especially after water main work or in older plumbing.
- Shut off the toilet water at the wall.
- Flush the toilet to lower the tank water level.
- Open the fill valve cap per the valve's locking tabs or top cap style without forcing brittle plastic.
- Rinse loose grit from the cap and inlet area with clean water only.
- Reassemble the cap, turn the shutoff back on slowly, and test the refill.
- If the refill improves but still acts erratic, the valve may be partly worn out and close to failure.
Next move: If the tank now fills at a normal speed and shuts off cleanly, debris was the problem. If there is still no refill or the valve only works briefly, replace the toilet fill valve.
Step 5: Replace the failed part and test the toilet
By this point the likely fix is usually a toilet fill valve, and sometimes a damaged toilet supply line found during inspection.
- Replace the toilet fill valve if the float moves freely, supply is available, and cleaning did not restore reliable refill.
- Replace the toilet supply line if it is kinked, crushed, leaking, or badly corroded at the ends.
- After replacement, open the shutoff slowly and let the tank fill.
- Set the water level to the marked fill line inside the tank or about 1 inch below the top of the overflow tube if no mark is present.
- Flush the toilet several times and watch for a full refill, proper shutoff, and no leaks at the supply connection or under the tank.
- If the toilet still will not refill even with a new fill valve and a good supply line, the shutoff valve or branch supply needs a plumber.
A good result: If the tank refills at normal speed and stops at the right level, the repair is complete.
If not: If a new fill valve still gets little or no water, stop replacing toilet parts and address the shutoff valve or supply problem.
What to conclude: You have confirmed whether the failure was inside the toilet or in the water supply feeding it.
Replacement Parts
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FAQ
Why is my toilet tank not filling after I flush?
Most often the shutoff valve is partly closed, the toilet fill valve is clogged with debris, or the toilet fill valve has failed. Start with the water supply at the wall before replacing tank parts.
Can a bad flapper cause the toilet tank not to fill?
Usually no. A bad toilet flapper more often causes running or repeated refilling, not a tank that stays empty with no incoming water. If the tank will not refill at all, focus on the supply line and toilet fill valve first.
Why does my toilet tank fill very slowly?
A slow fill usually points to a partly closed shutoff valve, a restricted toilet supply line, or sediment inside the toilet fill valve. Those are much more common than a drain problem.
Should I replace the toilet fill valve or try cleaning it first?
If the toilet recently had normal operation and then slowed down or stopped after plumbing work or sediment issues, cleaning the fill valve cap area is worth trying first. If the valve only works when tapped, sticks repeatedly, or still will not refill after cleaning, replace the toilet fill valve.
What if a new toilet fill valve still does not let the tank fill?
That usually means the problem is not inside the toilet anymore. The shutoff valve may be blocked internally, the toilet supply line may still be restricted, or the branch water supply has a problem. At that point, stop buying toilet parts and address the supply side.