A shower leak is a sure sign it’s time for repair work. Severe leaks may lead to mold, mildew growth, and damage to drywall, tiles, and floorboards. Depending on the type of shower faucet (some turn left or right to control hot and cold water, others use a lever), start by covering the drain with a towel. Then remove the handle and decorative cover plate, called an escutcheon

Severe Leaks
The most serious shower leaks can cause much damage, particularly if left untreated. Water can rot floorboards and joists and even swell plasterboard. In some cases, the walls and ceiling (if weight-bearing) may need to be replaced. It’s best to call in a plumber immediately before the problem worsens.
Visible water damage can also reduce the value of your home. Potential buyers will notice the issue and think twice about purchasing your property. Moreover, moisture can cause mold and mildew in the long run, and these problems are not only expensive to repair but may pose a health risk for you and your family.
To fix a severe leak, you’ll need to gain access to the shower pipes behind the wall. If you have an accessible panel on the other side of the wall, this will be easy; otherwise you’ll need to cut a window into the drywall. A reciprocating saw will be necessary to get the job done.
The first step is to remove the shower valve, replacing the old cartridge and escutcheon plate with new ones. Once this is done you can inspect the piping for the source of the problem. If it’s the shower arm, a new one can be installed by splicing in a section of pipe and using push-in fittings (SharkBite is one brand). In some cases, the problem may be the drop-ear elbow or vertical shower pipe.
If the problem is the drain, it’s necessary to re-seal the drain. This involves removing the old gasket and cleaning it thoroughly. Then a new sealant is applied and allowed to set. Once the new sealant has cured, the drain can be put back into place.
Crumbling grout is another sign of a problem that requires more than just re-caulking. If you suspect this, consider getting a quote for a full re-grout. Ideally, the new grout should be epoxy instead of cement-based, as it is resistant to both water and staining. It’s also worth considering a switch to a waterproof silicone caulk. This is available at most home improvement stores and costs a little more, but it’s worth it in the long run.
Mild Leaks
Often, shower leaks can start out small. Perhaps you notice a little water stain on the wall, or maybe your shower head starts leaking and you get that musty smell that tells you it’s time to do something about it.
Whether it’s a minor or mild leak, it’s important to get it taken care of as quickly as possible. Leaking showers can damage drywall and create mold growth, both of which are expensive and damaging to your home. They can also cause sagging of the ceiling and other structures within your home.
In addition to these structural issues, a leaking shower can present health concerns for those living in your home. Mold grows easily in damp conditions and some species of mold are known to pose a respiratory risk for people with weakened immune systems.
The first step in addressing your shower’s mild leak is to turn off the water supply. This is typically done by turning off the main water valve. Then, you’ll need to remove the shower head by unscrewing it. Be sure to keep track of the screw, nut and washer that hold the shower head to the valve, as you’ll need these items for your repair.
Next, examine the area surrounding the valve for signs of a leak. Look for areas where the grout is worn or cracked, as well as discoloration from mineral deposits. If you do find these signs, you’ll need to replace the grout, as it is not waterproof and can allow water to seep through and into your home’s structure.
If you do find that the grout is worn out, scrape it and clean the area thoroughly before re-grouting. Be sure to use a silicone caulk to seal the shower surround and prevent water from leaking into your home. After you’ve replaced the grout, be sure to test for a leak by running a bead of caulk around the edges of the tub and shower frame.
If you still cannot eliminate the leak, it may be necessary to replace the entire valve and showerhead assembly. This is more expensive, but it’s the best option for a long-term solution to your mild leak.
Moderate Leaks
If left untreated, even mild leaks can pose a serious threat to your home. Over time water can cause wood rot, mold growth and structural damage to drywall and support beams. Fortunately, you can often stop this from happening by catching a leak in its early stages and acting quickly to fix it.
Most shower leaks are caused by old or poorly-fitted shower fittings or tapware. Replacing these will often resolve the problem. However, some leaks may be hard to identify. For these, it is essential to check the entire assembly for damage and wear.
Leaks from shower handles are usually the result of worn out rubber gaskets or o-rings. These are easy to replace and can often be done at home. First, remove the shower handle by unscrewing it from the wall valve. You can find the screw under a circular plastic or metal covering in the center of each handle. Remove this cover and use a screwdriver to remove the screw inside. Once the handle is removed, you can then remove the decorative cover plate (also known as an escutcheon) and unscrew the shower valve stem or cartridge from the body.
Once you have removed the shower valve, you should be able to see the worn out O-ring that sits at the base of the stem. This is a common area for leaks and can be replaced easily with a new O-ring from the hardware store. Once the new O-ring is in place, you can reinstall the stem and the handle.
While bathroom tile adds aesthetic value to your home, it is also very functional in protecting the walls and floor from moisture. Any cracks or holes in the tile can allow moisture to penetrate into your home, leading to water damage. This can be expensive to repair, but is usually not as severe as a structural issue.
If you suspect a crack in your shower tile, you can try to repair it with silicone caulk. If this doesn’t work, it might be necessary to re-grout the entire shower. This is usually a cheaper option than replacing the tile, and will prevent moisture from penetrating into your home.
Minor Leaks
A minor leak is one that occurs around the valve or in the shower piping. These typically cause less damage than the more severe leaks, but still need to be repaired as soon as possible to prevent further water intrusion and damage to your home. You may notice damp walls or floors, musty odors, and even structural damage such as wood rot.
If you notice any of these signs, it’s time to sleuth out the source of the leak. This may require some detective work, but it’s well worth the effort to avoid expensive repairs and to protect your home from mold and rot.
Small leaks that are not addressed quickly can cause permanent damage. This is especially true for older houses with drywall that can absorb moisture and cause it to swell or shrink over time. This can create a gap in the drywall and allow water to seep behind it. This can lead to rot and mold and will also cause the drywall to detach from the wall frame. This can be a very expensive repair and should only be undertaken by a qualified plumber.
Often the first sign of a minor leak is visible discoloration and damage to the flooring or drywall near the shower. You might also notice water stains on the ceiling or joists below your shower. Leaving these leaks unrepaired can lead to costly water damage and can lower the value of your house.
If the problem is not too serious, it may be enough to simply re-seal your grout lines and caulking. However, this is only a temporary solution and you should consider replacing the caulking or grout entirely for a long-term repair.