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 if your water carries sediment, a valve you can open and clean out is worth having.
Below are our five top fill valves for 2026, chosen by use case so you can match one to your exact situation. We test these valves ourselves and cross-check current models against manufacturer specs and long-term owner feedback, 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 Fluidmaster's quiet PerforMAX, with a boosted bowl refill and a height range that fits most tanks. |
$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 Korky's TOTO-specific fill valve, which Korky's site lists for all TOTO toilet models. |
$14-$22 | ★★★★★ 4.6 | Check price |
| 4 | Best Budget Fluidmaster 400A Anti-Siphon Universal Toilet Tank Fill Valve Fluidmaster's classic budget valve, which it calls the #1 selling fill valve in the world. |
$8-$13 | ★★★★☆ 4.4 | Check price |
| 5 | Best Valve and Flapper Kit Korky 818MP QuietFILL Platinum Fill Valve and Flapper Kit Korky's quiet 528MP fill valve and its standard adjustable 2-inch flapper in one box. |
$17-$26 | ★★★★★ 4.6 | Check price |
Fluidmaster 400AH PerforMAX Universal High Performance Toilet Fill Valve
Key features: 2X greater bowl refill for 1.6 GPF and lower toilets (Fluidmaster's figure) · Height-adjustable shank: 10 to 15 inches · Roller clamp regulates the bowl fill level · Anti-siphon, code-approved · 7-year manufacturer warranty
Pros
- Fluidmaster bills it as its quietest, most powerful fill valve
- A stronger flush on today's low-flow toilets
- Adjusts an inch taller than the 400A
- Longest warranty of any pick here
Cons
- Slightly more expensive than the basic 400A
- Aimed at newer high-efficiency toilets rather than older high-volume tanks
Who it's for: Owners of newer low-flow toilets who want a quiet, no-fuss replacement for a worn or noisy fill valve.
Korky 528MP QuietFILL Platinum Toilet Fill Valve
Key features: Proven quietest in lab testing, per Korky · Twist-lock height adjust: 8.5 to 14 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
- Goes lower than either Fluidmaster valve here, down to 8-1/2 inches
- Tool-free twist-lock height adjustment
- Made in the USA with a solid 5-year warranty
Cons
- Korky makes no bowl-refill claim to match the 400AH's 2X figure
- Best suited to modern 1.6 GPF and lower toilets
Who it's for: People bothered by a noisy refill, or with a tank just a little too short for the Fluidmaster valves.
Korky 528T Replacement TOTO Toilet Fill Valve
Key features: Specific fit for TOTO toilets · Adjustable height, no tools needed · Comes with the refill tube, clip and install hardware · Made in the USA · 5-year warranty
Pros
- Higher refill ratio for TOTO toilets, per Korky
- Korky says it runs quieter than other fill valves
- Made to fix slow-refilling, running and noisy TOTO toilets
Cons
- Overkill if you don't own a TOTO toilet
- Costs a bit more than a basic universal valve
Who it's for: TOTO owners replacing a running, noisy or slow-filling valve who want a part made for TOTO tanks instead of a universal one.
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
- Not as quiet as the PerforMAX, which Fluidmaster bills as its quietest valve
- No 2X bowl refill, and a 5-year warranty against the 400AH's 7
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: Red rubber part 100 flapper; Korky lists chlorine, hard-water and well-water resistance · Fill valve fits 99% of toilets, per Korky · Flapper adjusts from 1.28 to 5 GPF · Refill tube, metal clip and install hardware included · Made in the USA, 5-year warranty
Pros
- Covers the two parts Korky calls the most commonly replaced in a toilet
- Dial on the flapper tunes how long it stays open
- Same quiet valve as our quiet pick
Cons
- More than a valve-only purchase
- Flapper is extra if your old one is still good
- Comes with Korky's standard flapper; the Ultra 2X, with rubber Korky calls twice as strong as other flappers and a 10-year warranty, is sold separately
Who it's for: Anyone whose fill valve and flapper are both worn, or who wants to replace both in one trip into the tank.
What matters before you buy
- Height adjustment range. Fluidmaster and Korky both size the valve off the overflow tube, not the tank: its critical-level (CL) mark has to sit 1 inch above the top of the overflow tube, a plumbing-code requirement both print in their instructions. On a Fluidmaster 400A, the top of the valve goes 3 inches above the overflow tube, and the tank lid must still sit down without touching it. On a Korky, the stamped water-level mark goes about 1/2 inch below the top of the overflow tube, which puts the CL mark in the same place. The listed height ranges tell you whether a valve can reach that setting in your tank: 9 to 14 inches for the Fluidmaster 400A, 10 to 15 for the 400AH, and 8-1/2 to 14 for Korky's QuietFILL Platinum. Once it's in, the water should stop at the tank's waterline mark, or about 1/2 inch below the top of the overflow tube if there isn't one.
- Toilet age and flush volume (GPF). Korky calls its QuietFILL Platinum ideal for toilets built from 1994 on, which use 1.6 gallons per flush or less, and Fluidmaster's catalog aims the PerforMAX 400AH at those same high-efficiency toilets. Older tanks are a different case: Fluidmaster lists its 400A as best for toilets made before 1994 that use 3.5 to 7 gallons per flush. 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. Korky says calcium, sediment and other debris can build up inside a fill valve and slow the refill. Its QuietFILL Platinum has a strainer that catches sediment, and a Korky valve can be taken apart and cleaned when it slows down. For the flapper, the 818MP kit page lists chlorine resistance for the kit's red rubber, and the page for that same flapper (part 100) adds bacteria, hard water and well water. The tougher Ultra 2X, made with Korky's Chlorazone II rubber, is the hard-water pick in our best toilet flappers guide.
- Bowl refill and warranty. Refill claims are about the bowl, not how fast the tank fills. Fluidmaster lists 2X greater bowl refill for the PerforMAX 400AH on toilets using 1.6 GPF or less, for a more powerful flush. Also check the warranty: the Fluidmaster 400A and Korky QuietFILL Platinum carry 5 years, and Fluidmaster gives the 400AH 7.
How we ranked these
We tested these valves ourselves, and we compared current 2026 models against manufacturer specifications (bowl refill, 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. Pick a valve whose height range lets its critical-level (CL) mark sit 1 inch above the top of your overflow tube, the position Fluidmaster and Korky both require, 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. Disconnect the supply line, unscrew the old valve's locknut under the tank and lift the valve out. Set the new valve's height before you fit it, then drop it in and hand-tighten the locknut. Reconnect the supply line, clip the refill tube to the top of the overflow tube, and turn the water back on. The water should stop at the tank's waterline mark, or about 1/2 inch below the top of the overflow tube if there isn't one.
Fluidmaster or Korky, which brand is better?
Both are excellent and you can't go wrong. Fluidmaster's 400AH is rated for 2X greater bowl refill on newer toilets and carries a longer 7-year warranty, while Korky's valves are made in the USA, run very quiet, and adjust slightly shorter, down to 8-1/2 inches. If you want one universal pick, go Fluidmaster 400AH. If quiet is your priority or you own a TOTO, lean Korky.
Why does my toilet keep running or hissing?
A constant run or hiss usually traces back to the fill valve or the flapper, and the pattern tells you which. If water keeps flowing after the tank is full, Korky says the float may be set too high, clogged with debris or failing to shut off, and adjusting, cleaning or replacing the fill valve fixes it. If the valve instead switches on every so often, a worn flapper or flush valve seal is usually letting tank water slip into the bowl. When both parts are worn, a combo kit like the Korky 818MP replaces them in one trip.
Are these fill valves universal, or do I need an exact match?
Most are universal. Fluidmaster lists universal fit for all its fill valves, including the 400AH and 400A, and Korky says its valves, including the 528MP in the 818MP kit, fit 99% of toilets. TOTO is where a dedicated valve earns its place: Korky makes one specifically for TOTO toilets, with a higher refill ratio it says suits them. That is our TOTO pick above, sold on Amazon as the 528T, which the listing says contains Korky's 528GT valve.
How long should a fill valve last?
Korky puts a fill valve's typical life at 5 to 7 years, depending on your water, since some water carries sediment that builds up inside the valve. Before you blame a slow valve, make sure the shut-off behind the toilet is fully open and the supply line isn't kinked. After that, Korky's advice is to service a Korky valve that is still in good shape and to replace one that is damaged or more than five years old.
Related guides & comparisons
- Best toilet flappers
- How to clean a toilet tank
- Best toilet bowl cleaners
- How to replace a toilet fill valve
- How to adjust a toilet float
- Toilet leaking? Find the source
Sources
- Fluidmaster — 400A Fill Valve Installation Instructions (PDF)
- Fluidmaster — Retail Catalog, fill valve specifications (PDF)
- Fluidmaster — 400A Universal Fill Valve (toilet age and fit)
- Korky — 528 QuietFILL Fill Valve Instructions (PDF)
- Korky — QuietFILL Platinum Toilet Fill Valve (528MP)
- Korky — QuietFILL Platinum Fill Valve and 2-Inch Flapper Kit (818MP)
- Korky — 2-inch Ultra High Performance flapper, part 100 (the flapper in the 818MP kit)
- Korky — Genuine TOTO Toilet Fill Valve (528GT)
- Korky — Ultra 2X Long Life flapper (Chlorazone II)
- Korky — How to replace a toilet fill valve (fill valve lifespan)
- Korky — How to fix a slow-filling toilet tank
- Korky — How to fix a running toilet
- Kohler — Toilet troubleshooting guide, waterline mark (PDF)