Best Toilet Fill Valves
A fill valve is the tall part inside your toilet tank that refills it with water after every flush. When it wears out, you get the classic problems: a toilet that runs forever, hisses, refills painfully slowly, or randomly cycles on in the middle of the night. The good news is that a fill valve is one of the cheapest and easiest plumbing parts to replace yourself, usually in 15 to 20 minutes with no special tools.
The catch is that not every valve fits every toilet, and the cheapest one is not always the right one. Tank height, how old your toilet is, your water quality, and even how quiet you need it all change the best pick. A modern low-flow toilet wants a different valve than a 1980s tank, and a home on well water needs rubber that won't crumble in a year.
Below are our five top fill valves for 2026, chosen by use case so you can match one to your exact situation. We researched current models, manufacturer specs, and long-term owner feedback rather than testing units ourselves, and every pick is a current, in-stock product on Amazon.
| # | Pick | Price | Rating | |
|---|---|---|---|---|
| 1 | Best Overall Fluidmaster 400AH PerforMAX Universal High Performance Toilet Fill Valve The fill valve most pros reach for: fast, quiet, and it fits almost any tank. |
$11-$18 | ★★★★★ 4.8 | Check price |
| 2 | Best for Quiet Operation Korky 528MP QuietFILL Platinum Toilet Fill Valve A near-silent, made-in-USA valve with the widest height range for fast installs. |
$13-$20 | ★★★★★ 4.7 | Check price |
| 3 | Best for TOTO Toilets Korky 528T Replacement TOTO Toilet Fill Valve A drop-in fix made specifically for TOTO G-Max and Power Gravity tanks. |
$14-$22 | ★★★★★ 4.6 | Check price |
| 4 | Best Budget Fluidmaster 400A Anti-Siphon Universal Toilet Tank Fill Valve The classic, dirt-cheap valve that has quietly fixed millions of running toilets. |
$8-$13 | ★★★★☆ 4.4 | Check price |
| 5 | Best for Hard Water Korky 818MP QuietFILL Platinum Fill Valve and Flapper Kit A fill valve plus chlorine-resistant flapper kit built to survive hard and well water. |
$17-$26 | ★★★★★ 4.6 | Check price |
Fluidmaster 400AH PerforMAX Universal High Performance Toilet Fill Valve
Key features: Refills the tank up to 2x faster than a standard valve · Height-adjustable shank: 10 to 15 inches · Quiet-fill design cuts the hiss and rattle · Anti-siphon, code-approved · 7-year manufacturer warranty
Pros
- Strong, fast refill keeps the next flush ready
- One of the quietest valves you can buy
- Fits the widest range of toilets, old and new
- Long 7-year warranty for the price
Cons
- Slightly more expensive than the basic 400A
- All-plastic build feels less heavy-duty than rubber-body valves
Who it's for: Anyone replacing a worn-out fill valve who just wants the safe, do-it-all pick that quiets a running or slow toilet.
Korky 528MP QuietFILL Platinum Toilet Fill Valve
Key features: Quieter than most competing fill valves · Twist-lock height adjust: 7.75 to 13.5 inches · Made in the USA · Refill adjuster sets the right bowl water level · 5-year warranty
Pros
- Very quiet fill, great for bathrooms near bedrooms
- Widest low-end height range fits short tanks others miss
- Tool-free twist-lock height adjustment
- Made in the USA with a solid 5-year warranty
Cons
- Fill speed is good but not quite the 400AH's 2x rate
- Best suited to modern 1.6 GPF and lower toilets
Who it's for: People bothered by a noisy refill, or anyone with an unusually short tank that other valves cannot adjust down to.
Korky 528T Replacement TOTO Toilet Fill Valve
Key features: Built for TOTO G-Max and Power Gravity models · Made in the USA · Quiet QuietFILL-style refill · Includes the hardware needed for install · Easy, no-tools height adjustment
Pros
- Matches TOTO's refill behavior better than a generic valve
- Avoids the higher cost of a TOTO OEM part
- Quiet and quick to install
- Made in the USA
Cons
- Overkill if you don't own a TOTO toilet
- Costs a bit more than a basic universal valve
Who it's for: TOTO toilet owners who want a clean, correct refill without paying for the pricier TOTO-branded OEM valve.
Fluidmaster 400A Anti-Siphon Universal Toilet Tank Fill Valve
Key features: Anti-siphon, code-approved design · Height-adjustable: 9 to 14 inches · Replaces old-style ballcock valves · Corrosion-resistant plastic · 5-year warranty
Pros
- Lowest price of any valve here
- Proven, time-tested design that just works
- Great match for older high-volume tanks
- Simple to install, parts included
Cons
- Refills slower and a bit louder than the PerforMAX
- Lacks the fast 2x fill and quiet-fill tech of newer valves
Who it's for: Budget-minded DIYers, landlords, and anyone with an older high-volume toilet who just needs a reliable, no-frills replacement.
Korky 818MP QuietFILL Platinum Fill Valve and Flapper Kit
Key features: Chlorazone red rubber resists hard, well, and chlorinated water · Includes both fill valve and 2-inch flapper · Quiet QuietFILL Platinum refill · Height adjusts 7.75 to 13.5 inches · Made in the USA, 5-year warranty
Pros
- Chlorine-resistant rubber lasts longer in hard water
- Fixes the two most-failed parts at once (valve + flapper)
- Quiet and tool-free to adjust
- Made in the USA with a 5-year warranty
Cons
- More than a valve-only purchase
- Flapper is extra if your old one is still good
Who it's for: Homes on well water, in hard-water regions, or with heavy chlorine treatment that chew through standard rubber parts.
What matters when choosing a bidet seat
- Height adjustment range. The valve has to fit your tank's height with the water line below the overflow tube. Most quality valves telescope to adjust. Korky's valves go as short as 7-3/4 inches, which is handy for compact or low-profile tanks, while Fluidmaster's typically run 9 to 15 inches. Measure from the bottom of the tank to about an inch below the overflow tube before you buy.
- Toilet age and flush volume (GPF). Toilets made since 1994 use 1.6 gallons per flush or less, and most modern valves are built for them. Older tanks can use 3.5 to 7 gallons, and they fill better with a higher-flow valve like the Fluidmaster 400A. Check the date stamp inside your tank lid or behind the bowl, and match the valve to it.
- Quiet operation. A loud refill is usually the valve, not the pipes. Newer 'quiet fill' designs (like the Fluidmaster PerforMAX and Korky QuietFILL Platinum) muffle that hiss and rattle. If your bathroom is near a bedroom or the noise drives you crazy, pay the extra couple dollars for a quiet-rated valve.
- Water quality and rubber type. Hard water, well water, and heavy chlorine treatment eat ordinary rubber, which is why some valves and flappers fail in a year. Korky's chlorazone (red) rubber is built to resist that. If you're on a well or in a hard-water area, choose a valve and flapper rated for it so you're not back inside the tank next spring.
- Fill speed and warranty. Faster refill means the next flush is ready sooner, which matters in busy or single-bathroom homes. The Fluidmaster PerforMAX refills up to twice as fast as a standard valve. Also check the warranty: 5 years is normal, and Fluidmaster's 7-year coverage on the 400AH is a good sign of confidence in the part.
How we ranked these
We did not bench-test these valves ourselves. Instead we compared current 2026 models against manufacturer specifications (fill speed, adjustment range, GPF compatibility, rubber type, and warranty), then weighed that against the long-term reliability themes and complaints that show up repeatedly in owner and plumber feedback. We prioritized real fit and durability over flashy features, picked one clear winner per common situation so the badges don't overlap, and confirmed that every product is a live, purchasable listing on Amazon.com before including it.
Frequently asked questions
How do I choose and replace a toilet fill valve?
First, turn off the water supply at the wall and flush to empty the tank, then sponge out the rest. Measure your tank height (bottom of tank to about an inch below the overflow tube) so you pick a valve with the right adjustment range, and check whether your toilet is pre-1994 (high flush volume) or newer (1.6 GPF or less). For most modern toilets the Fluidmaster 400AH is the safe pick; for older high-volume tanks the Fluidmaster 400A is ideal. Unscrew the old valve's locknut under the tank, drop in the new valve, hand-tighten the locknut, reconnect the supply line and refill tube, then turn the water back on and adjust the height so the fill stops below the overflow.
Fluidmaster or Korky, which brand is better?
Both are excellent and you can't go wrong. Fluidmaster's 400AH tends to refill faster and carries a longer 7-year warranty, while Korky's valves are made in the USA, run very quiet, and adjust to shorter tank heights. If you want one universal pick, go Fluidmaster 400AH. If you need extra-quiet, a very short tank, or hard-water-resistant rubber, lean Korky.
Why does my toilet keep running or hissing?
A constant run or hiss almost always traces back to the fill valve or the flapper. If the valve never fully shuts off, water keeps trickling into the overflow tube and the valve cycles to top it off. Replacing a worn fill valve fixes the hiss and the phantom refills; if the tank still drains slowly, the flapper is leaking too, which is why a combo kit like the Korky 818MP is a smart buy.
Are these fill valves universal, or do I need an exact match?
Most quality fill valves are universal and fit roughly 99% of toilets, including the Fluidmaster 400AH, Fluidmaster 400A, and the Korky 528 and 818MP. The main exception is TOTO toilets, which can be fussy about refill timing. TOTO owners should use a valve built for them, like the Korky 528T, for the most reliable bowl level.
How long should a fill valve last?
A good fill valve typically lasts 5 to 7 years, and many run far longer. Water quality is the biggest factor: hard water, well water, and high chlorine shorten the life of standard rubber parts. If you're on a well or in a hard-water area and you keep replacing valves, switch to one with chlorine-resistant chlorazone rubber to stretch the lifespan.