Plumbing

Why Does My Faucet Keep Running When I Turn On My Shower?

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Everything You Need to Know About Your Shower's Diverter Valve

Showering is something you do fairly frequently. You’re no stranger to stepping in the shower, turning on the faucet, and adjusting the taps to get the perfect water temperature. Nobody has to tell you how to stop the water from coming out the spigot and have it come out of the showerhead instead, right? Of course not! But have you ever thought about what forces the water to flow to your showerhead instead of the spigot? If you're like most homeowners, probably not.

If you’ve ever turned your shower on but noticed that there was still water running from the tub’s faucet, you may have wondered what was wrong with your shower. You’d probably be especially frustrated by the lack of pressure coming from your showerhead because it makes it difficult to shower properly. 

If your tub’s spigot continues to run even when you turn on your shower, you most likely have an old or faulty shower diverter valve. 

What is a Shower Diverter Valve?

Valves are everywhere in your plumbing. When you turn on your sink, garden hose, and tub, you are using valves. They even help determine your water temperature when you turn on the sink or shower.

A valve is what keeps the water from flowing through your faucet and sends it to your showerhead instead. Although you’ve probably never heard it called a "diverter valve," that is the part of your shower that you turn, push, or pull to send the water coming from your tub’s faucet to your showerhead. It does exactly what it’s named for: it diverts (changes direction) water from one place to another.

Download the shower diverter graphics here.

The only problem with shower diverter valves is they don’t last forever, and there are many times—like all of the other components of your home—when they fail from old age and normal wear and tear.

There are two types of shower diverter valves:

Three-Valve Shower Diverter

Animated graphic of how a three-valve shower diverter works.
Download the shower diverter graphics here.

A three-valve shower has three different handles that you turn to open or close the valves. One handle opens the hot water valve, one opens the cold water valve, and the third (generally in the middle of the temperature valves) diverts the water into the spigot or up to the shower head.

As you turn the valves for the hot and cold valves, depending on the temperature you want the water to be coming out of your spigot, you increase or decrease the opening of each valve. Once you get the right temperature, you can keep the water running into your tub, or twist the diverter valve 180 degrees to divert the water up into the showerhead.

When water pours into the tub through the spigot, the valve is open. When the handle is turned 180 degrees, the valve moves forward and a rubber washer plugs the spigot of the tub so no water can get through.

A diagram of the three-valve shower diverter shower.
Download the shower diverter graphics here.

 Instead, the water is forced through a small number of holes in the valve which build pressure, sending the water up through the shower’s pipe and out of the showerhead.

The third valve diverter looks like this when it is working:

How the three-valve shower works to divert the water away from your tub spigot.
Download the shower diverter graphics here.

Tub Spigot Diverter Shower

Your tub keeps running if your shower diverter isn't working.

There are a number of different ways this shower looks. Some showers have two handles that regulate temperature, which open the cold and hot water lines separately. The water mixes together before coming out of the spout. Other showers have one handle that opens both of the water lines, and depending on how far the handle is turned, determines how much each of the two water lines is opened and how hot or cold the water is by mixing the water temperatures. Either way, the diverter valve is generally found on the spigot of the tub.

Your tub keeps running if your shower diverter isn't working.
Download the shower diverter graphics here.
This diverter valve is something you pull up or out to plug the water from coming into the spigot, diverting it up into the showerhead. When the diverter is pulled, it pulls a rubber (or sometimes plastic piece) into the hole where the water pours through, plugging spigot where the water normally flows. With this escape-route sealed off, the water has only one place to go: up and into the shower head. 
A tub spigot shower diverter diagram.
Download the shower diverter graphics here.
How the tub spigot diverter valve works.
Download the shower diverter graphics here.

Why would my diverter not be working?

Although diverter valves are a fairly simple way to control whether or not water flows from the tub to the showerhead, if they break down and fail, they could cause other major problems in your bathroom.  There are a few reasons why your shower may either have water flow through both the tub’s spigot and the showerhead at the same time or not flow at all. If you find that you’re having problems with your showerhead and tub running at the same time or you can't divert water to the showerhead, you may need to have your diverter replaced.

(It’s important for us to mention that if you’re a home warranty customer, you won’t have to do any investigation into why your diverter valve isn’t working – in fact, if you try to investigate the problem yourself and fail, the repair may not even be covered by your home warranty! If you open a claim with your home warranty company right away, though, you could only have to pay a small service call fee.)

Here are some reasons why a diverter may be failing to bring water into a showerhead:

Blocked Diverter:

In both types of diverter valves, if there’s something that’s blocking the diverter from closing or opening all the way, it could cause water to pour out of both spigots at the same time.

If you have a spigot that has the diverter directly inside of the spigot, you can see if there is something that’s blocking the diverter from closing all the way. You may need to soak the faucet in vinegar overnight to soften calcium build-up or clean it out with a small soft brush.

What may be causing your tub's spigot to keep running even when you turn on the shower.
Download the shower diverter graphics here.

With the three-valve shower, if you can take the shower faucet off easily, you can try and open the valve and see if there are any blockages within the valve and brush them off with a clean cloth.

Broken Washer

Some diverters rely heavily on rubber or nylon washers to make sure the holes to the spigot are properly closed. If these washers crack, fall apart, or get bent, they could be the cause of the problem with the diverter. If you see a broken or cracked washer, this is something that will need to be replaced.

Corrosion

Sometimes the threads on the crew that connect the spout to the pipe can corrode. The spout’s finish could also flake off and cause blockages in the shower. If this is the case and the faucet isn’t replaced, it could cause water to leak out on the wall behind the shower, which could cause rot, mold, or mildew.

If corrosion or a broken washer is the cause of your diverter woes, you’ll probably need to replace the diverter valve. Not sure how to do that? Not to worry! We have an article on how to replace the diverter valve on your shower

Learn how to replace the shower diverter valve here.

Wait! Are You a Landmark Home Warranty Customer?

If you’re having problems with your diverter valve, listen up! Don’t take your shower apart to see if there’s a problem. If you have a home warranty and your shower diverter valve has failed from normal wear and tear, you can have everything fixed and paid for, for a small service call fee! If you try to do it yourself, then you may not have the repair or replacement covered. If you're not a home warranty customer and you have no interest in saving hundreds of dollars on home repairs like broken diverter valves, read our article on how to replace a shower diverter valve

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