This article is part one of our leak inspection and repair blog series that explores bathtub leaking causes and solutions.

Have you recently noticed water stains on your ceiling or walls? Worse yet, is your drywall bubbling from exposure to moisture? If so, you could be dealing with a leaky bathtub that could jeopardize your health and home if left unaddressed.

Bathtub leaking can cause severe water damage, potentially wasting thousands of gallons of water every year. Even a minor leak can cause your water bill to increase by 10%. It can also lead to serious health concerns, including mold and mildew exposure, chemical hazards, and even electrocution.

The problem should therefore be assessed immediately—either by yourself or with the assistance of a master plumber. In either case, your first step is to determine if you have a bathtub leak. Next, you should investigate the cause of the leakage, which could result from user error, waterproofing issues, shower valve, or tub drain failure.

Signs Your Bathtub Is Leaking

To protect your home, it’s important to look out for early signs of bathtub leaking. If left unchecked, it could ruin your drywall, leading to wood rot and costly structural damage.

Whether your bathtub is leaking intermittently or consistently, you can expect to find the following signs of leakage in your home:

• Wet drywall underneath the bathtub 
• Mildew or mold around the perimeter of the shower
• Pooling water

When investigating bathtub leaking, be aware that water takes the path of least resistance. It can end up pooling in rooms that are adjacent to the bathroom, so be sure to examine the bathroom and all surrounding areas for water accumulation or damage.

If you’ve identified signs that your bathtub is leaking, your next step is to determine what is causing the leak.

What Can Cause a Bathtub to Leak? (Intermittant Leaking)

If your bathtub is leaking discontinuously (only during or immediately after use), the problem is typically easy to address and does not involve plumbing issues. The two main culprits of intermittent leaking are user error and lack of waterproofing.

1. User error: Water spillage

Surprisingly, the majority of household leaking problems are caused by water splashing onto the floor during bathing. Keep in mind that neither your tile floor nor your bathroom walls are fully waterproof. Water out of the tub will therefore seep through the floors or walls when given the chance. If you’re careful to dry off any spills after bathing, you could eliminate your leaking issues completely.

2. Waterproofing issues: Tile without grout or caulk

When water spills onto your bathroom floors or wall, missing caulk, grout, or tiles will exacerbate the problem. To troubleshoot potential waterproofing issues, quickly scan the perimeter of your tub to see if caulk or grout is fully covering the area. Pay special attention to where the tile meets the bathtub, and examine the areas your shower walls connect. If it looks like any crevices are not properly sealed, recaulk or grout your tiles as soon as possible, which should prevent your bathtub from further leaking.

What Can Cause a Bathtub to Leak? (Consistant Leaking)

While intermittent leaking usually results from non-plumbing-related issues, regular leaking is typically a sign of plumbing fixture problems. Water that persistently leaks from the bathtub is often due to faulty shower valves or tub drains.

3. Shower valve leak troubleshooting

If you notice constant dripping from your spout or showerhead after the water is turned off, you could be facing a shower valve leak issue. This often means the valve behind the shower handle (i.e., the fixture you use to turn your water on and off) is defective. Fortunately, most shower valves can be replaced fairly easily in under a few hours.

4. Tub drain leaking troubleshooting

The final most common leak issue comes from the tub drain. If you notice signs of leaking downstairs (on the ceiling below your bathtub) it’s likely due to a tub drain malfunction that’s located at the overflow drain or waste drain assembly:

• The overflow drain is the small hole (often covered by a round metal disk) that prevents your bathtub from overflowing. If you regularly notice leaking, but it only occurs while someone is taking a bath, you most likely have an overflow drain issue. Leaking usually happens when the bathtub is filled past the overflow plate and the gasket is deteriorated or dry-rotted.

• The waste drain assembly includes your drain stopper and a series of interconnected pipes located below the bathtub drain. It’s responsible for draining unwanted water from your bathtub. If regular leaking occurs—whether or not you’re using the shower or bath and you’re sure it’s not a shower valve leak—it’s most likely coming from your waste drain assembly.

Whether you believe your tub drain or shower valve is responsible for your leaking problems, it’s important to fix the issue as soon as possible to prevent water damage that could elevate your water bills and eventually damage your home.

Look out for more articles from our Leak Inspection and Repair Blog Series, which overview:

• Part 1 – You’re here.
• Part 2 – Bathtub drain leaking (waste drain repair)
• Part 3 – Bathtub overflow drain leak repair
• Part 4 – Shower valve leaking repair (for two- or three-handle valves)
• Part 5 – Leaking shower valve repair (for one-handle Moen fixtures)
• Part 6 – Adjusting your trip-lever drain stopper: ​​Why your ​​tub doesn’t hold water

If you’re in need of additional leak detection and repair solutions or are looking for a reliable plumber in Rockville, MD or the surrounding areas, contact Heil Plumbing DMV today.

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Heil Plumbing DMV is a family-run company owned by a third-generation master plumber. We can help you with a full range of plumbing services, including toilet installation and repair, leak detection and pipe repair, water heater repair and installation, faucet repair and installation, drain cleaning, water treatment, and more.