5 Best Toilet Fill Valves – For a Quiet and Fast Refill

Last Updated on May 18, 2022 by toilethaven

A toilet fill valve is toilet tank part that is responsible for filling the tank with water after every flush. It is normally located on the left-hand side of the toilet tank.

The fill valve is installed vertically in the tank with the help of a locknut on the underside of the tank. A water supply line which is made of braided stainless steel or sometimes plastic is also connected to the fill valve from the underside of the tank.


The water supply line draws water and links the fill valve to the toilet shut off valve. A toilet shut off valve is the knob on the wall behind the toilet. It allows you to turn off water to the toilet when performing toilet repairs.

Inside the toilet tank, the fill valve is connected to the toilet float and overflow tube through the refill tube. The toilet float moves up and down the tank relative to the tank’s water level, where it controls opening and closing of the fill valve.

A toilet’s refill tube is a thin (most black) tube that is connected from the fill valve to the overflow tube. The overflow tube is the large tube inside the tank which is part of the flush valve.

As the fill valve is filling the tank, the refill tube sends a little amount of water down to the bowl through the overflow tube. This is the water that is always at the bottom of the bowl. It prevents unpleasant sewer gases from coming up the bathroom.

The 5 Best Toilet Fill Valves

Although toilets generally last for many years, fill valves and other toilet tank parts will need to be replaced from time to time. Most of these parts are made of plastic with rubber seals that wear out after continued usage and hence necessitating replacements.

So, what is the best toilet fill valve for a replacement? While looking to buy a fill valve to replace to replace your old one, there are 2 ways to go about. You can either buy a universal fill valve manufactured by a third party or you can buy an exact replacement from your toilet manufacturer.

These are the 5 best toilet fill valves:

  • 1. Fluidmaster 400AH PerforMAX
  • 2. Toto TSU99A.X Universal Fill Valve
  • 3. Kohler Genuine Part Gp1083167
  • 4. Fluidmaster 400CRP14 Universal Toilet Fill Valve
  • 5. Korky 528 Universal Fill Valve

1. Fluidmaster 400AH PerforMAX Universal High Performance Toilet Fill Valve

If you are looking for the best universal toilet fill valve then the Fluidmaster 400 AH high performance fill valve will be worth your while.

Why do I say this is the best universal fill valve? The Fluidmaster 400AH (also known as the 400ARHR) is not only made of high quality materials but refills your toilet twice as fast as other standard fill valves.

One question I often have people ask me is “What is the difference between the Fluidmaster 400AH and the Fluidmaster 400CRP14”?

Fluidmaster 400CRP14 is designed for older toilets models with a higher consumption of 3.5 gallons per flush or more. The Fluidmaster 400AH on the other hand is designed for high efficiency (low-flow) toilets with a flush rate of 1.6/1.28 gallons per flush or even less.

Although the Fluidmaster 400AH is specially designed for high efficiency toilets, older toilet models with a high consumption rate can still use it without any issue. The 400AH is also compatible with dual flush toilets.

Another feature I like in the Fluidmaster 400AH is the water-saving roller clip on its refill tube. The refill tube is the small tube that send a little amount of water back to the bowl during flushing. This roller clip lets you control/adjust the water level in your bowl as you please.

Installing the Fluidmaster 400AH PerfoMax fill valve is a cinch. It will take you about 10 minutes. Whether you have a Toto, Kohler, American Standard or any other toilet brand this fill valve will be a perfect fit.

The height of the 400AH can be adjusted from 10 to 15 inches to fit toilet tanks of different heights. Although it is not the quietest fill valve, Fluidmaster has done a good job to ensure that it is not very noisy given its fast refill rate.

To show how confident the manufacturer is with this product, it comes with a 7-year warranty. You can then be guaranteed that you are buying a quality product.


2. Toto TSU99A.X Universal Fill Valve

If you have a Toto toilet that needs a fill valve replacement, chances are that you will be happy to buy an original Toto fill valve. In that case, the Toto TSU00A.X universal toilet fill valve is what you are looking.

It is compatible with most Toto toilets whether new, old, one-piece or two-piece. Its height can be adjusted to fit in Toto toilet tanks of different heights.

As you know, Toto toilets regardless of their flushing system have a 3-inch flush valve which is an inch larger than most toilets. This allows them to dump water in the bowl faster, and hence their strong flushing power.

You therefore want to buy a fill valve that will properly coordinate with the flush valve and other toilet specifications.

Korky makes an exact replica of this fill valve, dedicated to Toto toilets. If that would interest you, check out the Korky 528T Toto replacement fill valve here. It is cheaper that the Toto TSU99A.X and still works the same way.

Just like most Toto products, the Toto TSU99A.X fill valve comes with a 1 year warranty. The one from Korky comes with a 4-year warranty.

I genuinely can’t say which one among the 2 is the better than the other but I would personally lean towards the Toto-made fill valve.


3. Kohler Genuine Part Gp1083167 Silent Fill Valve Kit

If you have a Kohler toilet and only want an original fill valve replacement part from Kohler then this is the one you need to buy. It is slightly expensive than a third party universal fill valve but it works flawlessly.

One thing to note is that Kohler makes 2 models of this fill valve. There is this particular model and there is the Kohler Gp1138930 fill valve. So what is the difference between the Kohler Gp1083167 and Gp1138930 and which should you buy?

The Kohler Gp1138930 fill valve has a black shank and is specifically made for Kohler Class Five toilets, while the Kohler Gp1138930 has grey shank and is designed for all of their other older toilets.

If not for the Kohler branding at the top of fill valve, you wouldn’t tell this fill valve apart from the Fluidmaster 400AH PerforMAX fill valve. This is not a problem however since the Fluidmaster fill valve works perfectly on Kohler toilets.

The Kohler fill valve however comes with multiple fill-rate inserts to optimize performance and conserve water. Its refill is also a silent/quiet but quick.

If you are using an older Kohler toilet please order the Kohler Gp1138930 fill valve here. If you have a newer model utilizing the Class Five flushing technology then order the Gp1083167.


4. Fluidmaster 400CRP14 Universal Toilet Fill Valve

The Fluidmaster 400CRP14 toilet fill valve is the most popular universal fill valve in the market. It is both efficient and cost-effective.

What I like about this product is that instead of receiving a fill valve only, you get a toilet flapper too. These are the 2 toilet parts that will most likely trouble you and the best thing is to always replace both of them.

The 501 Fluidmaster’s toilet flapper contains Microban, an antimicrobial substance that prevents it from bad odors, staining and breaking down. This flush valve is designed for toilets with a 2-inch flush valve.

Fluidmaster’s 400CRP14 is not for all toilets. According to Fluidmaster, you should only buy these fill valve for a toilet with flushing rate of 3.5 gallons per flush or more. It is therefore not ideal for low-flow toilets.

The height of the 400CRP14 toilet fill valve can be adjusted from 9 to 14 inches. You can therefore be sure that it will fit toilets with small and those with big tanks.

For those people who still have the old-school float ball fill valves, this fill valve would be more than a perfect replacement. It comes with a 5-year warranty


5. Korky 528 Universal Fill Valve

The Korky 528 universal QuietFILL toilet fill valves are high quality, great performing and durable fill valves, best known for a quiet refill. They are designed and manufactured in Wisconsin, United States.

Korky universal fill valve is designed to fit most toilet brands including Toto, Kohler and American Standard, whether they are one-piece or two-piece toilets. I have however heard a few complaints of it not being compatible with some Kohler toilet models, none of which I have encountered myself.

The good thing is that this fill valve will work perfectly with any toilet, be it an old model with a high consumption or the new high efficiency toilets. You can also adjust its height from 7.75 to 13.5 inches. Its easy twist-lock adjustment makes it easy to adjust its height even after being fully installed.

Unlike other fill valves which come with a long plastic screw for adjusting the water level in the toilet tank, the Korky fill valve is different. You need to hold the top cap and twist it, then pull it up or down until the correct water level is attained.

Its refill tube also features a dial that lets you adjust the water level in the bowl. You may need to flush your toilet a couple of times before getting it right.

If you need to replace your old ballcock, have a slow filling or noisy toilet then the Korky QuietFILL universal toilet fill valve will be a decent pick for a replacement.


Full Toilet Tank Repair Kit?

Sometimes it makes sense to do a full toilet tank rebuild. This involves replacing all the toilet tank parts all at once, especially if you have not done so in a couple of years. I have seen old toilets flush like new ones by doing this.

The advantage of doing this is that it is cheaper to buy a complete kit than buying one part time at a time. You also get the chance to do everything at the same time instead of replacing one part at a time over a long time.

If you would like to give your toilet a complete makeover then these are the kits that I would recommend:

1. Fluidmaster 400AKRP10 Universal Toilet Repair Kit

This repair kit comes with a fill valve, flapper, flush valve, toilet tank to bowl gasket, tank bolts, flush handle and all the necessary seals. It is basically everything you would need to put in your toilet and have it flush like a new one all over again.

It is a universal repair kit and will therefore fit in most toilets. The kit comes with a 5-year warranty and at a great price.


2. Korky 4010PK Universal Complete Toilet Repair Kit

The Korky universal complete tank repair kit comes with everything that the Fluidmaster’s kit comes with except a handle. It comes with the Korky QuietFILL fill valve and toilet flapper for 2-inch flush valve toilets.

It is compatible with old as well as modern high efficiency toilets from most brands. The kit has a 5-year warranty.


It is important to note that replacing all the toilet tank parts takes longer than just replacing a fill valve. To replace the flush valve, toilet tank to bowl gasket and tank bolts you will first need to remove the tank.

It is however not a difficult task. I have written these detailed guides to help you do this repair on your own without needing to call in a plumber:

Once you complete this repair, you can rest assured that your toilet will serve you well for at least the next 5 years.

Before buying a toilet fill valve there are some factors to consider to make sure you end up with the best one, one which will fit and work perfectly for you. These factors include:

  • Quality/durability
  • Fill rate
  • Noise level
  • Toilet compatibility
  • Adjustable length
  • Warranty
  • Brand

How a Toilet Fill Valve Works


The moment you enter the bathroom and prior to you flushing the toilet, the tank is normally full of water up to just about ½ inch below the overflow tube.

After doing your business and flushing, the toilet float which was until that time floating at the top of the tank falls down towards the bottom of the tank. Since the float is connected to the fill valve, its downward movements opens the valve and the tank starts to fill with water.

As the level of water in the tank rises, the float moves up with it until its set height when it stops and shuts the fill valve. At this point the refill cycle is complete.

It is always important to make sure that the refill tube is properly clipped on the overflow tube. If that is not the case you will have a low water level inside the toilet bowl.

The water level in the tank also affects the overall performance of the toilet. When the toilet tank water level is too low, you will have a slow flushing toilet, which means you will need to flush it more than once.

Ideally, the water level inside the tank should be about ½ inch below the overflow tube. Remember to adjust the toilet float accordingly after replacing the fill valve.

Toilet Fill Valve vs Flush Valve

Often, most people confuse between a toilet fill valve and a flush valve. So what is the difference between a fill valve and a flush valve?

A fill valve is the opening through which water enters the tank after flushing while a flush valve is the opening at the bottom of the tank through which water leaves the tank and enters the bowl during flushing.

A fill valves goes hand in handle with a toilet float while a flush valve goes hand in hand with a toilet flapper. A flapper is the seal that sits at the top of the flush valve to prevent water from flowing to the bowl unless during flushing.

The fill valve is involved with the toilet’s refill cycle while the flush valve is involved with the toilet’s flush cycle. Older toilets have a 2-inch flush valve but modern low-flow toilets have a 3 or a 4–inch flush valve.

Types of Toilet Fill Valves

Although toilet fill valves are largely universal, it depends on the particular type as there are several types of fill valves. These is something you need to consider before buying replacement a fill valve for your toilet.

The 3 common types of toilet fill valves are:

1. Ballcock/Float Ball Fill Valve

A float ball which is also known as a ballcock is the oldest type of type of fill valve. It consists of a balloon-like plastic ball connected to the valve using a rod.

The name float ball came from the fact that the ball is always floating when the tank is full. After flushing the toilet the ball falls to the bottom of the tank allowing the tank to start filling.

Although new ballcocks are still available in home improvement stores, modern toilets don’t use them anymore. Most of the new fill valves use its working principle however.

2. Float Cup Fill Valve

A float cup which is also known as float cylinder fill valve has a small cylindrical cup mounted on the fill valve’s vertical assembly. It is more compact than a float ball and that is why it is the favorite choice of fill valve for modern toilets.

Float cup fill valves comes as a complete kit compromising the fill valve and the float and is cheaper to buy. You can replace an old float ball fill valve with a modern float cup fill valve, which also refills fast.

3. Floatless/Pressure-Activated Fill Valve

According to the laws of physics, fluids (in this case water) exerts pressure in the container it is held, in this case the toilet tank. The more the water or the higher the level of the water the more the pressure it exerts.

Floatless or pressure-activated toilet fill valves are installed at the bottom of the tank and instead of relying on floats to open or shut water flow, they do so by detecting changes in water pressure in the tank. They are set to automatically open or set when the water level reaches a certain level.

When to Replace a Toilet Fill Valve

Although fill valves can be fixed, if the one you have has served you for a couple of years then replacing it is the way to go. These parts are generally inexpensive hence a replacement makes more sense.

How do you know that your toilet fill valve is bad and that it is time to buy a new? The following are the telltale signs that your fill valve has seen better days and that a replacement is the only viable solution.

1. Constantly Running Toilet

A constantly running toilet is not only irritating but it can be very expensive too. Water endlessly trickles from your tank to the bowl.

A running toilet is caused by either a faulty toilet flapper or fill valve. When the problem is with the flapper, water seeps from underneath the flapper but with a faulty fill valve water flows down to the bowl via the overflow tube.

To determine whether the problem is with the flapper or the fill valve, lift off the tank lid and check the water level. If the water is so high that it is flowing down through the overflow tube, you have a problem with the fill valve.

The solution can be a fill valve replacement or adjustment of the float.

2. Noise From the Toilet

When your toilet makes a humming/hissing/screaming noise then you need a fill valve replacement. The sound is normally experienced after flushing the toilet as the toilet is refilling.

A screaming toilet is a sign that water is not flowing as freely as it should, indicating a blockage of the waterway by either debris or mineral deposits. It could also be as a result of loose fill valve parts.

3. When It’s too Old

Sometimes you might want to replace your fill valve and other toilet tank parts after say 5 years of continuous usage. The reason for doing this is that you do not want to wait until they are completely worn out in order to replace.

New toilet parts function better than old ones. If you toilet is taking too long to refill or if it is not flushing as powerfully as you may want it then you can decide to change the toilet tank parts and give it a few more years of life.

How to Replace a Toilet Fill Valve

Toilet fill valve replacement is a simple task that you can comfortably do on your own. You really don’t need to pay a plumber to do this task for you. It will take you around 15-20 minutes even without prior plumbing experience

Here are the steps to follow:

1. Empty your Tank

  • Turn off the water flow to your toilet. The shut off valve is located on the wall behind your toilet.
  • Flush the toilet and hold the level down until most of the water has been flushed down
  • Remove the toilet tank lid and place it away in a safe place.
  • Since there is still some water left at the bottom of the tank, use a sponge or rag to soak it up until the tank is completely empty.

2. Remove the Old Fill Valve

  • Disconnect the water supply line from the fill valve on the underside of the tank. Use your hands and not a wrench as you do not want to deform that coupling.
  • Locate a lock nut that holds the fill valve firmly on the toilet, still on the underside of the tank. Unscrew that one too,
  • Unclip the refill tube from the overflow tube and lift off the fill valve.
  • Clean the bottom of the tank and the fill valve opening prior to installing the new one.

3. Install the New Fill Valve

  • Check the fill valve gasket at the top of the threads to make sure it is well positioned at the very top of the threads.
  • Slide the fill valve through the hole at the bottom of the tank but don’t tighten it yet.
  • Measure the distance between the top of the fill valve and the top of the overflow tube. The fill valve top cap should be about 3 inches higher than the top of the overflow tube. Remove the fill valve and adjust it accordingly.
  • Put the fill valve back and tighten it in place using the new locknut.
  • Connect the water supply line on the new fill valve.
  • Clip the refill tube on the overflow tube. If it is too long cut it down in size. You do not want it too deep inside the overflow tube. It can siphon out the water in the bowl.
  • Turn on the water supply from the shut off valve

4. Adjusting the Toilet Fill Valve

  • Note the level of water inside the tank, relative to the top of the overflow tube. If it is not about ½ below the overflow tube you will need to adjust the fill valve float.
  • Look for a long plastic screw alongside the body of the fill valve. By turning it clockwise or counterclockwise, the water level in the tank will fall or rise respectively.


A toilet fill valve is one of the most important toilet tank parts. With a a faulty one you almost don’t have a toilet. While looking looking to buy the best fill valve to replace your old one, Fluidmaster and Korky make the best universal fill valves. You could also decide to go with one specially made by your toilet manufacturer.