Best French Toilets (2026)
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Toilet Bowl Empties Then Slowly Refills
A toilet that empties and then refills slowly is a symptom of a specific mechanical failure, not a design flaw. This guide explains exactly what causes this cycle, how to diagnose it in under 10 minutes, and which toilet models are least susceptible to the issue.
Why Trust Best Flushing Toilets
- Flushing power and MaP flush-test scores
- Water efficiency (GPF and EPA WaterSense)
- Aggregated owner reviews
- Clog resistance and trapway design
- Brand reliability and warranty
Research updated June 2026.
Quick Answer
The "empties then slowly refills" cycle is almost always a failing flapper or a misaligned fill valve. The flapper closes too early or leaks, causing the bowl to drain partially. The fill valve then runs to restore water, but does so slowly due to a clogged inlet screen or worn diaphragm. Replacing the flapper and cleaning the fill valve usually fixes it. For a permanent solution, upgrade to a toilet with a 3-inch flapper and a pressure-assisted flush system.
| Model | MaP Score | GPF | Flush Type | Trapway | Height | Best For |
|---|---|---|---|---|---|---|
| TOTO Drake II CST454CEFG | 1000g | 1.28 | G-Max (3 in. flapper) | 2-1/8 in. | 17 in. | Reliability |
| Kohler Highline K-3987 | 1000g | 1.28 | Class Five (3 in. flapper) | 2-1/8 in. | 16.5 in. | Slow refill fix |
| American Standard Champion 4 | 1000g | 1.6 | PowerWash (4 in. flapper) | 2-3/8 in. | 16.5 in. | Clog resistance |
| Woodbridge T-0001 | 1000g | 1.28 | Dual flush (3 in. flapper) | 2 in. | 16.5 in. | Budget fix |
| Gerber Viper 21-522 | 1000g | 1.28 | Vortex (3 in. flapper) | 2 in. | 16.5 in. | Commercial use |
Why does my toilet bowl empty then slowly refill?
The root cause is a flapper that fails to stay open long enough for a full flush, combined with a fill valve that cannot keep up with the demand. The flapper closes prematurely, allowing the tank to refill while the bowl is still partially empty. The fill valve then runs slowly because of debris or a worn diaphragm.
When you flush, the flapper lifts and water rushes from the tank into the bowl. A properly functioning flapper stays open until the tank is nearly empty, allowing a full siphon to clear the bowl. If the flapper is warped, dirty, or has a weak hinge, it closes too early. This stops the flush mid-cycle, leaving the bowl empty or partially empty. The tank then refills, but the fill valve is often restricted by calcium buildup or a torn washer, causing a slow refill.
Expert Take
In 90% of cases, the flapper is the culprit. Replace it with a universal 3-inch flapper from Fluidmaster or Korky. Clean the fill valve inlet screen by turning off the water, removing the valve cap, and rinsing the screen. If the slow refill persists, replace the fill valve entirely with a Fluidmaster 400 series.
How do I diagnose a toilet that empties and refills slowly?
Remove the tank lid and flush. Watch the flapper: if it drops before the tank is empty, it is faulty. Listen to the fill valve: a hissing or sputtering sound indicates debris. Check the water level in the tank after the flush stops; if it is below the overflow tube, the fill valve is slow.
Start by removing the tank lid and flushing the toilet. Observe the flapper. It should lift fully and stay open until the tank is nearly empty. If it wiggles, drops early, or does not seal properly after the flush, replace it. Next, listen to the fill valve. A steady hiss or a sputtering sound means the inlet screen or diaphragm is clogged. Finally, measure the water level in the tank after the refill stops. It should be about 1/2 inch below the top of the overflow tube. If it is lower, the fill valve is not delivering enough water.
Expert Take
Use a simple test: add a few drops of food coloring to the tank water. If the color appears in the bowl within 15 minutes without flushing, the flapper is leaking. This leak can cause the bowl to empty slowly and the fill valve to run intermittently.
What toilet models prevent the empties and slow refill problem?
Toilets with a 3-inch or larger flapper and a pressure-assisted flush system are least likely to experience this issue. Models like the TOTO Drake II, Kohler Highline, and American Standard Champion 4 use larger flappers that are more reliable and less prone to premature closing.
The problem is common in toilets with 2-inch flappers, which are more sensitive to wear and misalignment. Upgrading to a toilet with a 3-inch flapper provides a larger opening that allows water to flow faster and more consistently. Pressure-assisted toilets, such as the TOTO UltraMax II, use compressed air to force water out, eliminating the flapper mechanism entirely. These models are virtually immune to the slow refill issue.
Top Pick
TOTO Drake II CST454CEFG
This toilet uses a 3-inch G-Max flapper and a 2-1/8 inch trapway, making it one of the most reliable models for preventing the empty-and-slow-refill cycle.
Flush TypeG-Max (3 in. flapper)
GPF1.28
MaP1000g
Trapway2-1/8 in.
Height17 in.
WarrantyLifetime
Pros
- Large 3-inch flapper reduces early closure
- MaP score of 1000g for clog resistance
- WaterSense certified at 1.28 GPF
Cons
- Higher price point than budget models
- Requires specific TOTO flapper replacement
The TOTO Drake II features a 3-inch flapper that is more robust than standard 2-inch versions. This larger flapper stays open longer, ensuring a complete siphon and preventing the bowl from emptying prematurely. The fill valve is also designed with a larger inlet screen to resist clogging. Owner reviews consistently report fewer issues with slow refills compared to older TOTO models.
For those who already have a TOTO toilet, replacing the flapper with the genuine TOTO part (THU173S) is recommended. Aftermarket flappers may not seal properly, leading to the same problem.
Expert Take
Check price on AmazonThe Drake II is the gold standard for reliability. If you are replacing a toilet specifically to avoid the empty-and-slow-refill problem, this is the model to choose. Its G-Max flush system is proven in MaP testing to clear 1000 grams of waste with a single flush.
Bottom Line: The best all-around solution for preventing the empty-and-slow-refill cycle, backed by a lifetime warranty and top MaP scores.
Best Value
Kohler Highline K-3987
The Kohler Highline uses a Class Five flush system with a 3-inch flapper, offering a reliable fix at a lower price point than the TOTO.
Flush TypeClass Five (3 in. flapper)
GPF1.28
MaP1000g
Trapway2-1/8 in.
Height16.5 in.
WarrantyLifetime
Pros
- Class Five flush is very consistent
- 3-inch flapper is easy to replace
- Affordable compared to TOTO
Cons
- Some users report noise during flush
- Fill valve can be slow if not maintained
The Kohler Highline is a popular choice for those who want a reliable toilet without the premium price. Its Class Five flush uses a 3-inch flapper that is less prone to warping than smaller flappers. The fill valve is a standard Fluidmaster design, making replacement simple. Owner reviews highlight that the Highline rarely experiences the empty-and-slow-refill issue, even after years of use.
To maintain performance, clean the fill valve inlet screen annually. If the toilet does start to empty slowly, replacing the flapper with a Kohler genuine part (1054545) usually resolves it.
Expert Take
Check price on AmazonThe Highline is the best value option for avoiding the slow refill problem. Its 3-inch flapper is more durable than the 2-inch flappers found on cheaper models, and the fill valve is easy to service.
Bottom Line: A cost-effective solution that offers the same 3-inch flapper reliability as the TOTO, but at a lower price.
Best Clog Resistance
American Standard Champion 4
The Champion 4 uses a 4-inch flapper and a 2-3/8 inch trapway, making it the most clog-resistant option and highly resistant to early flapper closure.
Flush TypePowerWash (4 in. flapper)
GPF1.6
MaP1000g
Trapway2-3/8 in.
Height16.5 in.
WarrantyLifetime
Pros
- 4-inch flapper is very reliable
- Largest trapway for clog prevention
- PowerWash rim jets clean bowl
Cons
- Uses 1.6 GPF, not WaterSense
- Flush can be loud
The American Standard Champion 4 is designed for high-performance flushing. Its 4-inch flapper is the largest available, ensuring it stays open long enough for a complete flush. The 2-3/8 inch trapway is the widest in the industry, reducing the chance of clogs that can cause the bowl to empty slowly. The PowerWash rim jets also help keep the bowl clean, reducing buildup that can affect the flush.
This model is ideal for households with heavy use or older plumbing. The 1.6 GPF rating is not WaterSense certified, but the flush performance is exceptional. If you are experiencing the empty-and-slow-refill problem, upgrading to the Champion 4 will likely eliminate it.
Expert Take
Check price on AmazonThe 4-inch flapper on the Champion 4 is a game-changer for reliability. It is much less likely to warp or close early than smaller flappers. Combined with the large trapway, this toilet is virtually immune to the slow refill issue.
Bottom Line: The best choice for households that need maximum clog resistance and a flapper that will not fail prematurely.
Budget Pick
Woodbridge T-0001
The Woodbridge T-0001 is a dual-flush toilet with a 3-inch flapper, offering a budget-friendly solution that still prevents the empty-and-slow-refill cycle.
Flush TypeDual flush (3 in. flapper)
GPF1.28 / 0.8
MaP1000g
Trapway2 in.
Height16.5 in.
WarrantyLifetime
Pros
- Dual flush saves water
- 3-inch flapper is reliable
- Very affordable
Cons
- Fill valve can be slow on low-flow flush
- Some users report flapper seal issues
The Woodbridge T-0001 is a budget-friendly dual-flush toilet that still uses a 3-inch flapper. This helps prevent the early closure that causes the bowl to empty. The dual-flush mechanism allows for a 0.8 GPF liquid flush and a 1.28 GPF solid flush. Some users report that the fill valve is slower on the low-flow flush, but this is not the same as the empty-and-slow-refill problem. The 2-inch trapway is smaller than the TOTO or Kohler, but still adequate for most households.
For the price, the Woodbridge T-0001 is a solid choice. If you are on a tight budget and need to replace a toilet that has the empty-and-slow-refill issue, this model will likely perform better than older 2-inch flapper toilets.
Expert Take
Check price on AmazonThe Woodbridge T-0001 is a good entry-level option, but the fill valve is not as robust as the TOTO or Kohler. If you choose this model, plan to replace the fill valve with a Fluidmaster 400 series after a few years.
Bottom Line: A budget-friendly dual-flush toilet that uses a 3-inch flapper, but the fill valve may need upgrading over time.
Commercial Grade
Gerber Viper 21-522
The Gerber Viper uses a Vortex flush system with a 3-inch flapper, designed for commercial use where reliability is critical.
Flush TypeVortex (3 in. flapper)
GPF1.28
MaP1000g
Trapway2 in.
Height16.5 in.
WarrantyLifetime
Pros
- Commercial-grade reliability
- 3-inch flapper is durable
- Vortex flush cleans bowl
Cons
- Flush can be loud
- 2-inch trapway is smaller
The Gerber Viper is built for commercial applications, meaning it is designed to withstand heavy use without developing the empty-and-slow-refill problem. Its 3-inch flapper is made from a more durable material than residential models, and the Vortex flush system ensures a complete siphon every time. The 2-inch trapway is smaller than the TOTO or Kohler, but the flush power compensates for it.
This model is a good choice for households with multiple bathrooms or for those who want a toilet that will last for decades. The fill valve is also commercial-grade, reducing the chance of slow refills.
Expert Take
Check price on AmazonThe Gerber Viper is a workhorse. If you want a toilet that will not develop the empty-and-slow-refill issue even after years of heavy use, this is the model to choose. It is not the prettiest, but it is the most reliable.
Bottom Line: A commercial-grade toilet that is built to last, with a 3-inch flapper and a durable fill valve that resist the slow refill problem.
Frequently Asked Questions
Why does my toilet bowl empty but not refill?
This is usually a failed flapper that does not seal, causing the tank to empty into the bowl. The fill valve then runs continuously but slowly because the tank never fills completely. Replace the flapper first.
Can a clogged fill valve cause the bowl to empty slowly?
Yes. A clogged fill valve reduces the flow of water into the tank. If the tank refills slowly, the bowl may not get enough water to complete the siphon, leaving it partially empty.
How do I fix a toilet that empties and refills slowly?
Turn off the water, flush to empty the tank, and remove the flapper. Check for warping or debris. Clean the fill valve inlet screen. Replace the flapper and fill valve if needed.
Is a 3-inch flapper better than a 2-inch flapper?
Yes. A 3-inch flapper allows more water to flow faster, reducing the chance of premature closure. It is also less prone to warping and misalignment.
What is the best toilet to prevent the empty and slow refill problem?
The TOTO Drake II with its 3-inch G-Max flapper is the most reliable. The Kohler Highline and American Standard Champion 4 are also excellent choices.
Can a pressure-assisted toilet have this problem?
Pressure-assisted toilets do not use a flapper, so they are immune to this specific issue. However, they can have other problems with the pressure vessel or fill valve.
How often should I replace the flapper?
Every 2 to 3 years, or sooner if you notice the toilet running or the bowl emptying slowly. Hard water can accelerate wear.
Does a slow refill mean I need a new toilet?
No. In most cases, replacing the flapper and cleaning or replacing the fill valve will fix the problem. Only consider a new toilet if the bowl is cracked or the flush mechanism is beyond repair.
Can a toilet flapper be too tight?
Yes. If the flapper chain is too tight, it can pull the flapper closed early, causing the bowl to empty. Adjust the chain to have 1/4 inch of slack.
What is the difference between a slow refill and a running toilet?
A slow refill means the tank takes a long time to fill after a flush. A running toilet means the fill valve runs continuously because the flapper is leaking. Both can be caused by the same parts.
Should I use a universal flapper or a brand-specific one?
Brand-specific flappers are recommended for TOTO and Kohler toilets because they are designed to seal properly. Universal flappers work for most other brands.
Can hard water cause the empty and slow refill problem?
Yes. Mineral deposits can clog the fill valve inlet screen and cause the flapper to warp. Use a water softener or clean the parts regularly.
Is it safe to use a toilet that empties and refills slowly?
It is safe, but it wastes water and can lead to incomplete flushes. Fix it as soon as possible to prevent further damage.
How much does it cost to fix a toilet that empties and refills slowly?
Replacing a flapper costs $5 to $15. A new fill valve costs $10 to $25. If you hire a plumber, expect to pay $100 to $200 for labor.
Sources
- EPA WaterSense, epa.gov/watersense
- MaP flush testing, map-testing.com
- Manufacturer published specifications
- Fluidmaster fill valve repair guides
- Korky flapper compatibility charts
Our Verdict
The "toilet bowl empties then slowly refills" problem is almost always a failed flapper or a clogged fill valve. Replacing the flapper with a 3-inch model and cleaning the fill valve inlet screen will resolve the issue in most cases. For a permanent solution, upgrade to a toilet with a 3-inch flapper, such as the TOTO Drake II or Kohler Highline. These models are designed to prevent premature flapper closure and have more robust fill valves. If you are on a budget, the Woodbridge T-0001 offers a 3-inch flapper at a lower price, but you may need to replace the fill valve over time. For maximum reliability, the Gerber Viper is a commercial-grade option that will last for decades.
How we rank & our data sources
We do not run physical lab tests. Rankings are built from published, verifiable data and real owner feedback, never paid placement.
- MaP (Maximum Performance) flush scores
- EPA WaterSense certification & GPF ratings
- Manufacturer specifications (trapway size, flush-valve, rough-in)
- Verified owner reviews from Amazon, Home Depot & Lowe’s
Researched by Marcus Bell · Last updated June 30, 2026 · Our review method
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