Top 10 Causes of Shower & Toilet Leaks in Concord—And How Pros Fix Them
Discover the peace of mind that comes with Service Pros Plumbers – where punctuality, quality work, and your complete satisfaction aren’t just promises, they’re our standard.
A small drip in your bathroom can turn into swollen subfloors, mold, and costly repairs—especially if it’s hiding behind tile or under your toilet. If you’re in Concord, CA (or nearby Antioch and Walnut Creek), here are the 10 most common causes of shower and toilet leaks, how professionals fix them, and simple ways to prevent a repeat.
1) Worn Shower Valve/Cartridge & O-Rings
Symptoms: Dripping showerhead when off, water behind trim plate, moisture inside wall.
Pro Fix: Replace the cartridge and worn O-rings, reseal the trim, and verify normal pressure. If the mixing valve body is corroded or cracked, we’ll replace it and bring it up to code.
2) Cracked or Loose Shower Arm / Drop-Ear Connection
Symptoms: Water inside the wall when the shower runs; ceiling stains below.
Pro Fix: Remove the arm, apply PTFE tape/pipe dope, and reinstall. If the drop-ear elbow is loose, we anchor and replace it to stop movement that causes recurring leaks.
3) Failed Shower Drain Gasket or P-Trap
Symptoms: Drips under the shower, damp ceiling below, odor.
Pro Fix: Pull and re-gasket the drain assembly, re-bed with plumber’s putty as needed, and replace a brittle or cracked P-trap. We always perform a water test afterward.
4) Tile Grout/Sealant Failure
Symptoms: Dark/grimy grout lines, damp corners, moisture outside the shower curb.
Pro Fix: Remove loose grout, regrout, and recaulk all plane changes (wall-to-floor, corners) with 100% silicone. For recurring issues, we assess waterproofing behind the tile.
5) Shower Pan Liner or Base Failure
Symptoms: Persistent dampness at the shower perimeter, soft subfloor, mildew smell.
Pro Fix: Perform a flood test. If the pan fails, options include a new receptor, or a rebuild with a modern waterproofing system. We dry the structure before closing up.
6) Tub/Shower Overflow or Waste & Overflow Gasket
Symptoms: Ceiling stains under the tub when bathing; dry when showering only.
Pro Fix: Replace the overflow gasket and waste shoe gasket, reseal connections, and confirm no hairline cracks in the tub.
7) Toilet Wax Ring or Flange Problems
Symptoms: Water at the toilet base, musty odor, soft or spongy flooring near the bowl.
Pro Fix: Pull and reset the toilet with a new wax or waxless seal, shim for stability, and repair/replace a broken flange. We test flush repeatedly to confirm the seal.
8) Tank-to-Bowl Gasket, Bolts, or Hairline Tank Crack
Symptoms: Drips between tank and bowl, water on the back of the bowl, slow puddles.
Pro Fix: Replace tank bolts, washers, and the tank-to-bowl gasket. If we find a porcelain crack, we’ll recommend a new tank or full toilet replacement.
9) Supply Line or Angle Stop Leaks
Symptoms: Water in the vanity/toilet shutoff area; intermittent spraying or hissing.
Pro Fix: Replace the supply riser with stainless-braided, swap a seeping angle stop, and ensure secure, leak-free compression fittings.
10) “Running” Toilet & Condensation (“Sweating” Tank)
Symptoms: Constant refilling sound; water on floor from condensation in humid rooms.
Pro Fix: Replace flapper and fill valve, set correct water level, and fix ghost flows. For sweat, we can add an anti-sweat mixing valve, improve ventilation, or install an insulated tank.
How We Diagnose Bathroom Leaks (Without Guesswork)
- Moisture & Thermal Imaging: Finds hidden dampness and hot/cold anomalies.
- Color/Drain Tests: Pinpoints overflow and drain gasket failures.
- Pressure & Isolation: Separates fixture issues from line leaks.
- Camera Scopes (as needed): Checks concealed drains for cracks, offsets, or clogs.
You’ll see what we see, and we’ll give clear, upfront options before repairs begin.
Prevention Tips for Concord Bathrooms
- Recaulk annually at tub/shower corners and around the base (leave a gap at the toilet base’s rear for leak detection).
- Use stainless-braided supply lines and replace them every 5–7 years.
- Keep pressure 55–75 PSI with a healthy PRV—high pressure shortens fixture life.
- Ventilate after showers to reduce condensation.
- Address “running” toilets immediately—it wastes water and worsens sweat issues.
Frequently Asked Questions
1) How do I know if my shower leak is from tile or from the plumbing?
If it only leaks when water hits the wall, suspect grout/caulk or a failed pan. If it leaks even when the shower isn’t in use—or drips behind the trim—it’s likely plumbing (valve, cartridge, or connections). We’ll test both.
2) Is a waxless toilet seal better than wax?
Both work. Waxless seals handle minor movement better and are cleaner to reset; wax is traditional and effective when the flange is at proper height. We choose based on flange condition and floor level.
3) Can I just recaulk around the toilet to stop a leak?
No. Caulk can hide leaks and trap water. The right fix is a new seal (and possibly flange repair). We usually leave a small caulk gap at the back for leak detection.
4) Why does my shower leak only sometimes?
Intermittent leaks often come from overflow gaskets, tile/grout gaps, or loose connections that only get wet under certain spray angles or water levels. Targeted testing finds the trigger.
5) Will you have to open my wall or floor?
Only if necessary. We start with non-invasive tools. When access is required, we make small, surgical openings and coordinate dry-out to protect your home.
Get Fast, Local Help—Contact Service Pros Plumbers
If you’re seeing ceiling stains, a soft floor around the toilet, or a shower that won’t stop dripping, get it checked before hidden moisture spreads. We diagnose and fix bathroom leaks quickly for Concord homeowners—and we serve Antioch and Walnut Creek too.
Use the online form on this page to contact Service Pros Plumbers now.
Tell us what you’re seeing, and we’ll respond promptly with next steps and a convenient service window.
Bathroom leak stress? Fill out the online form—Service Pros Plumbers will find it and fix it right.