Quick Answer:
If the problem is a small drip or a slow drain and you can shut the water off, it may be a DIY repair. Call a plumber when there are signs of hidden leaks, you cannot shut off the water, someone is getting scalded, noises continue, or you have repeated cartridge failures. As a first step, stop using the tub and follow what to do immediately if you suspect a major leak.
Why This Happens
- Worn or corroded valves and cartridges fail and cause leaks or poor temperature control.
- Loose fittings, cracked seals, or degraded caulk allow water to get behind tiles and into walls or floors.
- Poor installation or water quality can lead to repeated cartridge failures.
- Hidden pipe corrosion or damaged connections cause leaks behind walls that may not be visible until damage appears.
- Thermostatic or mixing valve failure can create a scald risk by letting very hot water through unexpectedly.
Step-by-Step What to Do
1. Turn off water to the tub
If you have a local shutoff for the tub, close it. If not, shut the house main only if necessary to stop active flooding. If you can’t shut the water off, stop using the fixture and call a plumber immediately.
2. Do a quick visible inspection
- Look for wet spots, stains, bulging or soft drywall near the tub, and new mold or mildew smell.
- Check grout and caulk lines, and the underside of any nearby panels or access doors.
- Listen for persistent noises like running water when everything is supposed to be off.
3. Quick checklist
- Can you shut off the tub or house water? (Yes/No)
- Is water visible or staining walls/flooring?
- Is anyone experiencing scalding or sudden hot water spikes?
- Are there persistent noises when fixtures are off?
- Have faucet cartridges been replaced multiple times recently?
- Any bulging or soft drywall near the tub?
4. Collect information to tell the plumber
- When the issue started and how it progressed.
- Which fixtures are affected (bath spout, shower, tub filler, etc.).
- Whether you can shut the water off and whether you have shut it off.
- If there is visible water damage, mold, or soft drywall.
- Any DIY steps you tried (including cartridge swaps) and how often they have failed.
- Fixture brand/model if known, and photos or short videos of leaks or noises.
- Access details: where the access panel is, or whether panels would need to be opened.
What Not to Do
- Do not keep using the tub with hidden leaks — that lets water damage and mold spread.
- Do not ignore electrical hazards near water; shut off power to affected areas if water reaches outlets or switches and stay clear until a pro checks it.
- Do not delay when structural or ongoing water damage is present — immediate action reduces repair costs.
When to Call a Professional
Call a plumber when any of the following red flags appear. These are signs the problem is beyond simple DIY fixes:
- Leaks behind walls or wet, bulging drywall.
- You can’t shut off the tub or the house shutoff is not working.
- Scald risk: sudden hot water surges, inability to control temperature.
- Persistent noises of running water when fixtures are off.
- Repeated cartridge failures despite replacements.
If you’re unsure whether to call, err on the side of safety and contact a professional — it helps to be ready to explain the checklist above and provide photos. If you need guidance on timing, see when to call a plumber.
Safety Notes
- Scalding can cause serious injury. If someone is being scalded, stop using the tub and call a plumber right away.
- Water and electricity are a dangerous combination. If water reaches electrical outlets, switches, lights, or any wiring, cut power to the area and call a qualified electrician or plumber before using the space.
- Mold and structural damage can follow hidden leaks. The longer a leak continues, the more extensive and expensive repairs become.
- Avoid risky DIY: do not open gas lines, cut into structural members, or attempt electrical repairs unless you are trained.
Common Homeowner Questions
- Can I replace a bathtub cartridge myself?
- Sometimes — if the shutoff works, you have the right part and basic tools. Repeated failures or unclear causes mean call a pro.
- How fast will hidden water damage happen?
- It can begin within days to weeks, especially in warm, humid areas. Prompt action reduces the risk of mold and structural harm.
- Will homeowner’s insurance cover a bathtub leak?
- It depends on your policy and the cause. Sudden damage is more likely covered than long-term maintenance issues. Document the damage and contact your insurer promptly.