Your toilet fill valve, also known as the ballcock, is a very important part of your toilet. Without it, the toilet wouldn’t be able to function properly. It’s also one of the most common toilet repairs that need doing. Chances are, as a homeowner, you’ll run into a toilet fill valve problem at some point. In this article, we give you the full scoop on toilet fill valves so you’re prepared: what they are, how they work, the different kinds available, and how to know when it’s time for a replacement part.

What Is a Toilet Fill Valve and How Does It Work?

The toilet fill valve is a valve located inside your toilet, attached to either a float cup or a float ball. The job of your fill valve is to refill the tank with clean water each time you flush the toilet. It does this through a series of controlled actions that maneuver it up and down inside the tank, all of which are essential to the functioning of your toilet.

First, the valve opens the water flow when you flush the toilet, which starts the toilet float movement to the bottom of the tank, allowing the water to exit the tank. Once the water has flown back into the tank, the float gradually rises and the valve then closes the water supply, but only once the water has reached the appropriate level.

There are a few different kinds of fill valves, depending on how old your toilet is. They all work in a similar way, but each has its own unique features.

Plunger Fill Valves

Plunger fill valves, also known as piston style fill valves, are one of the oldest styles of fill valves. They’re constructed of a cast brass body, designed to stand the test of time. The brass body also reduces noise, creating a quiet and smooth operation. This style of fill valve is characterized by its long arm and float ball, usually constructed of plastic, though older models are sometimes made from brass.

The design consists of a simple plunger valve. Most newer toilets won’t come with this style, but if you have an older toilet, the valve may still be installed and functional. When you flush the toilet, the stem that seals off water flow is lifted, and clean water rushes into the tank. The water rises, and along with it the float ball. Once it reaches the top of the tank, the valve is closed and the water stops.

These toilet valves can usually be fixed pretty easily, but if you’re ever in need of a replacement, you’ll probably have to go with a more modern fill valve.

Floatless Fill Valves

If you have a floatless fill valve, you might have overlooked it when you first opened the tank. This is because it’s located underwater, at the bottom of the tank. These models are another that aren’t often used anymore. In fact, older models of this are likely out of code and in need of replacing. This is because older models would sometimes malfunction and siphon toilet water back into the water supply. Some communities don’t allow floatless fill valves of any kind, even newer ones that have anti-siphon technology, so be sure to ask before installing this valve type.

Float Cup Fill Valves

Currently, the most popular type of fill valve and the kind you’re likely familiar with, float cup fill valves are both reliable and easy to install and work on. They’re considered universal since they can be adjusted for a variety of toilet heights and configurations. They’re also considered easier than other types to repair.

Unlike other types of fill valves where a float ball is connected to a lever, with float cup valves, there’s a float cup that connects to the valve via the stem. The float cup changes height inside the tank, moving up or down depending on the water level, opening or closing the fill valve depending on the position of the cup.

Diaphragm-Style Fill Valves

The last style of toilet fill valve is called a diaphragm-style fill valve. There are actually two different subtypes here: diaphragm fill valves with a plastic body and ones with a brass body. Brass models were common a number of years ago, making it possible that your toilet still has one installed. There’s nothing to be alarmed about if this is the case as even older models have anti-siphon technology built in. If you’re ever in need of a replacement, however, your plumber will probably use a newer model with a plastic body. Alternatively, they may replace your fill valve with a different kind altogether, most typically the float-cup style.

This style of fill valve is actually a modification of the older plunger-type model. Instead of a plunger-style valve, there’s a diaphragm controlling the seal of the valve and the inflow and outflow of water.

How Do I Know When My Toilet Fill Valve Needs Replacing?

Over time, parts on your fill valve begin to break down and wear out. If you notice one or more of the following signs, it’s time to give us a call. We’ll send a licensed plumber out to investigate and solve the issue for you.

  • Humming, screaming, or rattling noises
  • A toilet that won’t stop running
  • Toilet that fills slower than normal

Which signs you notice will largely depend on how bad the damage has gotten as well as what type of fill valve your toilet has installed.

Can I Replace My Toilet Fill Valve Myself?

If you’ve noticed problems with your fill valve, you might be wondering if you can fix it yourself, and the answer is that it depends on what type of fill valve you’re replacing and what, if any, plumbing experience you have. If you don’t even have a basic grasp of your plumbing system, the different components of your toilet, and how to use a basic set of handyman tools, it’s probably best to leave things to a professional. We’d be more than happy to send a member of our team out to your home to take a look. They’ll be able to diagnose the problem and make sure it really is the fill valve that needs replacing as well as get things fixed for you in no time at all.

Your Local Plumbing Experts

AZ Water, Drain & Sewer is a full-service plumbing company that provides services to residents in Gilbert, Arizona. Our plumbing services range from drain cleaning and sewer inspections to pipe repair, leak detection, and water heater installations for both tank and tankless models. With a variety of financing options and emergency services available for problems that can’t wait, we’re the pros ready to tackle any job. Give us a call today and schedule an appointment.

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