How To Repair A Leaking Tub Diverter Spout

Repairing a leaking tub diverter spout is a relatively easy task that most people can do themselves. It is normal for a small amount of water to come out of the spout when the shower is being used but when the amount is large enough and the shower water volume suffers the spout should be replaced.

The small amount of water bypassing the diverter and coming out of the spout is by design to allow the water in the shower riser to leak down and allow the diverter to reset so the next shower user does not receive a cold blast out of the showerhead when they turn on the water. Instead water will come out of the tub spout allowing them to set the water temperature. Most diverter tub spouts are inexpensively constructed and there is no repairs that can be performed on them, so replacing the spout is required. Most diverter spouts are of die cast construction and the metal may corrode allowing excessive leakage out of the spout while showering or, in some cases at the connection to the pipe stub coming out of the wall will start to leak. The connection to the pipe stub leaking in many cases is noticeable by water coming out of a drain hole on the bottom side of the tub spout where it meets the wall. In some cases if the drain hole has been caulked over or, the leakage is a higher flow than the drain hole can handle water will pour back inside the wall when the shower is running causing leaks to appear below the tub often damaging ceilings on the levels of the home below the tub.

There are three basic designs of diverter spouts for bathtubs with showers, and the tools required will vary depending on which type you have. The most common is probably a diverter spout that screws on to a pipe nipple or, pipe stub with a threaded adapter sweated onto the end of the spout. Rapidly gaining popularity because of the ease of installation and the expanding Do It Yourself marketing by many tub/shower mixer manufacturers is the slip on diverter spout, which uses a connection that slides over a copper pipe stub sealing with an o-ring and locking in place with a set screw onto the copper pipe stub. The last one is the Delta tub/shower diverter spout that has an adapter that either threads onto a pipe nipple or, is sweated onto a copper pipe stub coming out of the wall. The Delta tub/shower diverter spout is easily recognized by its unique appearance and the pull down diverter operation instead of lifting a knob.

Recognizing which tub/shower diverter spout is key to avoiding damage to your pipe coming out of the wall and making the job easier. If you attempt to turn a slip on tub spout that locks onto a copper pipe stub with a set screw you can very quickly turn an easy job into one that requires using a plumbers torch. In some cases if the original installer turned the spout after locking the set screw the set screw will no longer line up with the hole. If the spout is not a Delta pull down type spout in most cases it will have a die cast shell around the attachment. I usually cover the tub drain with a rag then crush the die cast shell with a pair of channel lock pliers exposing the attaching mechanism. If the spout threads on then I can use a wrench to hold back on the stub out of the wall while unthreading the spout or, easily see and remove the set screw holding on a slip on spout.

Screw On Diverter Spout Replacement

To replace a screw on diverter you will need a new spout matching the dimensions of the old spout for attachment or, be ready to adjust the stub out length possibly involving sweating copper pipe with a plumbers torch or, cutting the adapter off and using a slip on spout. To replace the spout with a matching spout you will need the spout, Teflon tape, Teflon paste, a measuring tape, channel lock pliers, a pipe wrench to hold back on the pipe nipple (if one is used coming out of the wall), an adjustable wrench to hold back on the threaded adapter (if copper pipe comes out of the wall), and something to put into the end of the spout to aid you in turning the spout tight. Unscrew the old spout off the stub and threaded adapter then wrap Teflon tape over the threads, apply Teflon paste over the tape and thread the new spout tightly into place ending with the spout facing in the down position and level. I have strong hands and can get it sufficiently tight but many people have to use something inserted into the spout to assist turning. Be careful not to damage the spout. Test for proper operation and leaks and the job is done. In most cases caulk is not required, and if you caulk the spout, you should only caulk the upper half of the spout where it meets the wall, never caulk the drain at the bottom closed.

Slip On Diverter Spout Replacement

To replace a slip on diverter spout you will need the new spout, plumber’s grease, possibly plumber’s cloth or, a file if there are burrs on the stub, and an allen wrench. Remove the slip on spout by loosening the set screw with the allen wrench. Slid the spout off the stub using a twisting, turning motion while pulling it off. Inspect the stub making sure there are no sharp burrs that will damage the sealing o-ring on the new slip on spout. If there are any burrs remove them with the plumber’s cloth or file before attempting to slip on the new spout. Apply a light coating of plumber’s grease on the stub to where the o-ring will sit when installed this will help prevent damage to the o-ring. Slide the new spout into position tightly against the wall and level with the spout facing down then use the allen wrench to tighten the set screw, taking care not to over tighter the screw into the copper tube. Test for proper operation and leaks and the job is done. In most cases caulk is not required, and if you caulk the spout, you should only caulk the upper half of the spout where it meets the wall, never caulk the drain at the bottom closed.

Delta Pull Down Diverter Spout Replacement

To replace a Delta pull down spout you need to pick up the new spout either the Delta # RP17453 plastic spout, or, # RP17454 metallic spout. Examine the new spout and how it attaches will be self-evident. Remove the old spout from the adapter on the nipple or stub out unthreading it from the adapter then pull off the old spout. Transfer the o-ring on the new spout’s adapter, to the old adapter mounted on the stub out, apply a light coating of plumbers grease to the o-ring. Then slide the new Delta pull down diverter spout onto the adapter and tighten it against the wall with the spout facing down and level locking it in place. Test for proper operation and leaks and the job is done.  In most cases caulk is not required, and if you caulk the spout, you should only caulk the upper half of the spout where it meets the wall, never caulk the drain at the bottom closed.

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45 comments on “How To Repair A Leaking Tub Diverter Spout
  1. JIM says:

    I am having a problem with my shower and spout both flowing water and leaking.This problem started very slowly a few months ago and has gotten worse.I have a 30+ year old Delta shower & tub fixture (single turn knob). I have replaced the spout( diverter on spout) and changed the springs & rubber cups in the unit. Leaking has stopped but the water does not stop flowing from shower & spout.Please help. Thank You

    • Redwood says:

      Hi Jim,
      Are you saying the water will not shut off or, that water comes out of both the tub spout and the showerhead when filling the tub?

      • JIM says:

        The water comes out both spout and showerhead.If I use the diverter on the spout,it will only come out of the showerhead,otherwise it comes out both.

        • Redwood says:

          Hi Jim,
          This could be several things, with this type of tub valve the waterway to the showerhead is always open but because the showerhead is so much higher than the tub spout and the flow to the tub spout is unrestricted the water takes the easier path to the tub spout instead of the showerhead. Once you block off the spout by pulling the diverter then the water goes up to the showerhead instead.

          Some of the possible causes in no special order would include:

          • A restriction in the pipes to the tub spout.
          • An incorrectly plumbed pipe to the spout using a material other than copper tube or IPS (Iron Pipe Sized) pipe.
          • The mixing valve plumbed in upside down so the restrictor normally on the shower is on the spout.
          • The shower was incorrectly plumbed with the showerhead too low so there isn’t enough backpressure.
          • The water pressure in your home is too high so the high volume of water to the spout is creating enough backpressure to send water up to the showerhead,

          Since you are saying the Delta Tub Faucet you have is over 30 years old, I’ll assume that it has worked correctly in the past and rule out many of the possibilities on that basis. I’d start by checking the pressure of the water supplied to your home. You may have a pressure reducing valve that has failed or, your water supplier may have increased the pressure they supply to your home. By code if the water pressure is 80 psi or, higher a pressure reducing valve is required, sometimes borderline high pressure may cause this to happen as it depends on the installed height of the showerhead in relation to the mixing valve. Watts makes a nice pressure gauge which can screw on to a hose bibb or, water heater drain and has a lazyhand which can record the highest pressure reached over the period of measurement these can be found at many hardware stores and home centers. It is a good idea to measure for at least 24 hours as the water supplier may vary pressure throughout the day with water usage peaks and as they fill water towers.

          In addition if the pipes used supplying the tub spout are galvanized or you have a water condition that causes scale buildup the pipes may be obstructed with scale or, rust which would cause this to occur.

          If you have high pressure please let me know and I can give you additional information.

          I hope this helps,

          • JIM says:

            I know the water pressure is not too high.We have hard water and now I’m thinking it is probably a scale buildup.I know very little about plumbing,so is there any way to remove the scale ?

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