Repair × Bathroom — 49 repair guides for the room where water meets electricity.

You came in through the Repair lane — here's everything repair-related for the bathroom. 49 guides covering the six systems that fail in bathrooms: toilets, faucets and valves, drains and venting, shower and tub, tile and grout, and the vent fan and GFCI electrical that every bathroom relies on. This is the same content you'd reach by entering through the Bathroom room hub's Repair slice; both URLs serve the same intersection because the site supports two equally valid mental models — "I want to repair something, what room am I in?" and "I'm in the bathroom, what can I fix?"

The bathroom is the most consequential room to repair correctly. Water in a bathroom is engineered — it runs to specific drains through specific traps with specific vent stacks. Electricity in a bathroom is regulated — every outlet within six feet of water must be GFCI-protected. Tile in a bathroom is a waterproofing system first and a surface second. Most bathroom repairs are simple and fast. The cost of not doing them is not. A running toilet wastes 200 gallons a day. Failed grout becomes a subfloor replacement. A cracked wax ring becomes sewer gas in the living space.

How to use this menu

This page is the Repair × Bathroom intersection, reached via the Repair lane. Browse the five highest-search repairs below if you came from a search engine. Use the category breakdown to find what broke by system. Every guide linked here is a leaf page Iris builds on demand — click any guide title to read the full step-by-step with tools, materials, time estimate, and pitfalls specific to that repair.

Five highest-search bathroom-repair projects

These five represent the large majority of bathroom repair searches. All five are within DIY range for a careful first-timer, and all five are repairs where waiting a week costs more than doing it today.

1. How to fix a running toilet

30 minutes. $10–35. Beginner. A toilet that refills itself every few minutes is losing water through a worn flapper or a misadjusted fill valve. A running toilet wastes up to 200 gallons per day — roughly $30 per month in water costs — and the fix is almost always a seven-dollar flapper that takes fifteen minutes to replace. The repair that costs thirty dollars today costs three thousand dollars if the water reaches the subfloor below. Read the running toilet guide →

2. How to replace a toilet flapper

15 minutes. $5. Beginner. The flapper is the rubber seal over the flush valve drain at the bottom of the toilet tank. It wears out every three to five years, and replacing it is the fastest plumbing repair in the house. Before you buy a new flapper, check the flush valve seat — a pitted or mineral-built-up seat will defeat a new flapper in a week. Read the flapper guide →

3. How to fix a leaky shower faucet

60 minutes. $20–80. Intermediate. A dripping shower faucet is almost always a worn cartridge — the internal valve body that controls water mixing and flow. Moen uses one cartridge design you pull straight up. Delta uses a ball valve. Kohler uses a ceramic disc. Buy the brand-specific replacement before you take anything apart, because you want the right part in hand before the water is off and the wall is open. Read the shower faucet guide →

4. How to unclog a bathroom drain

30 minutes. $5–15. Beginner. Bathroom drains clog with hair and soap. Pull the stopper, remove what's there by hand or with a drain snake in two passes, flush with hot water. If the drain is still slow after two snake passes, you're not dealing with a clog — you're dealing with a venting issue that needs a different diagnosis. Read the drain guide →

5. How to regrout a tile shower

4 hours plus cure time. $30. Intermediate. Cracked grout in a shower is not cosmetic. It's a gap in the waterproofing membrane. Water that reaches the backer board grows mold within 90 days and begins to rot the substrate within a year. Regrout every five to seven years. Re-caulk the tub-to-tile corner seam every two to three years. Read the regrout guide →

The full bathroom-repair menu, by category

49 guides total, organized by the system that failed — so you can find the right repair without knowing what the broken part is called.

Toilet repairs (12 guides)

Running toilets, ghost flushes, rocking toilets, weak or incomplete flushes, handle failures, and the wax ring that seals the toilet to the drain flange. The toilet has about twelve distinct failure modes — all fixable without a plumber if you have the right part and thirty minutes. The repair sequence: flapper first, fill valve second, wax ring third. The flapper is almost always the answer. Start with the running toilet guide →

Faucet & valve repairs (10 guides)

Bathroom sink faucets, single-handle shower cartridges, tub spout diverters, and the shutoff valves under the sink that need replacing before any other repair can happen. Every single-handle bathroom faucet has a cartridge or ceramic disc valve inside — the cartridge is the repair. Identify your brand before disassembly: Moen, Delta, Kohler, and Price Pfister all use different cartridges. Shower faucet guide →

Drain & venting (8 guides)

Slow drains, complete clogs, sewer smells at floor-level drains, and P-traps that need replacing when the drain arm has shifted. A drain that slows on every bathroom fixture simultaneously is a venting problem — the trap is being siphoned. A drain that smells like sewer without being slow is a dry trap or a cracked vent stack. Each has a different fix. Drain unclogging guide →

Shower & tub repairs (9 guides)

Shower arm replacement, diverter valve repair, tub spout removal and replacement, shower pan cracks, and the caulk bead between the tub and tile surround that fails every two years without exception. The shower is the wettest zone in the bathroom — address shower repairs on the first sign of a leak, not after the water has shown up somewhere it shouldn't be.

Tile, grout & caulk repair (5 guides)

Cracked grout lines, missing grout at corners and transitions, failing caulk at the tub-to-tile seam, and the tile that's come loose because adhesion has failed. The distinction: grout for field joints between tiles, silicone caulk for the corner seam where tile meets tub. Use grout in a caulk joint and it cracks within months. Use caulk in a field joint and the grout pattern breaks visually. Material matters. Regrout guide →

Vent fan & lighting (5 guides)

Bath vent fan motor replacement, fan-and-light combo repairs, GFCI outlet replacement, vanity light fixture swap, and the exhaust damper that sticks open in winter and lets cold air into the bathroom. The bath fan is the room's moisture control system — when it fails, mold follows. Fan motor replacement: $25 and 45 minutes. Mold remediation: $3,000 to $8,000 and a week. The math is not close.

Five mistakes specific to bathroom repairs

These five mistakes are bathroom-specific — they show up because the bathroom has unique plumbing geometry, finished surfaces, and electrical requirements that don't appear in other rooms.

Replacing a flapper without checking the flush valve seat. A new flapper on a worn seat leaks again within a week. Run your finger around the seat rim before installing any new flapper. If it's rough or pitted, address the seat first or the repair is temporary.

Using channel-lock pliers on chrome supply lines. Compression fittings on braided supply lines are hand-tight plus a quarter turn. Channel-locks on chrome crush the nut, score the ferrule, and create the leak you were trying to stop. Use an adjustable wrench and a rag to protect the chrome finish.

Caulking over old caulk. New silicone over old silicone lifts at the seam within 90 days. Complete removal, alcohol wipe, 24-hour dry, then fresh silicone — that's the only sequence that lasts.

Working on a GFCI outlet without confirming the breaker AND the GFCI test. The breaker and the GFCI are independent protection systems. A tripped breaker can leave a GFCI outlet energized if the GFCI hasn't also tripped. Confirm both with a non-contact voltage tester before touching any terminal.

Threading an ABS DWV trap without primer. ABS cement requires purple primer on every joint. A dry-fit trap holds pressure for months and then fails silently into the cabinet below. Always primer, always cement, always in that order.

Tools that earn their place in bathroom repair specifically

The 10-project bathroom-repair starter sequence

In order of complexity. Each project teaches a technique that the next one assumes. By project 10, you've touched every major bathroom system — plumbing, drain, tile, and electrical.

  1. Replace toilet flapper. 15 min, $5. Teaches tank anatomy and supply valve shutoff.
  2. Caulk a tub gap. 45 min, $8. Teaches tape-bead-tool-peel technique that applies to every wet seam.
  3. Tighten loose toilet handle. 10 min, free. Teaches reverse-thread awareness — most people strip the handle nut going the wrong direction.
  4. Replace shower head. 20 min, $25–80. PTFE tape on threads, hand-tight plus a quarter turn.
  5. Fix slow drain (snake). 30 min, $10. Teaches stopper removal and drain snake technique.
  6. Replace toilet fill valve. 30 min, $12. Teaches full tank anatomy and overflow tube relationship.
  7. Reseat a wobbly toilet (new wax ring). 90 min, $12. Teaches water shutoff, drain disconnection, toilet weight, and wax ring installation.
  8. Replace cartridge in single-handle faucet. 60 min, $20–40. Brand-specific — teaches valve body anatomy.
  9. Regrout a small tile section. 3 hr + cure, $20. Teaches grout saw, float angle, haze removal, and silicone at transitions.
  10. Replace bath fan motor. 45 min, $25. Electrical shutoff at breaker + GFCI test; motor slides out on a carriage.

Six common questions about bathroom repairs

Why does my toilet refill on its own every few minutes?

The tank is leaking into the bowl — ghost flushing caused by a worn flapper or a fill valve overflowing the overflow tube. Add food coloring to the tank; if color appears in the bowl without flushing, replace the flapper. If water is running into the overflow tube, lower the float on the fill valve.

What's the difference between a P-trap and an S-trap?

A P-trap has a horizontal outlet and maintains its water seal by geometry. An S-trap has a vertical outlet, is illegal under current plumbing code in most jurisdictions, and can siphon dry — allowing sewer gas into the room. If your bathroom sink drain exits vertically downward, you likely have an S-trap and should replace it with a P-trap and proper venting.

Should I caulk between the tub and the tile?

Yes — 100% silicone, never grout. The joint flexes with temperature and water weight; grout is rigid and cracks within months. Re-caulk every two to three years regardless of appearance.

Can I just paint over moldy caulk?

No. Cut out the old caulk, scrub with dilute bleach solution, dry 48 hours, confirm no remaining mold, then apply fresh silicone. Painting over mold traps it and lets the colony continue growing underneath.

Why does my bathroom smell like sewer?

Either a dry trap (a rarely-used fixture whose water has evaporated) or a failed wax ring (toilet rocks, seal has cracked, sewer gas escapes around the base). Run water into unused fixtures. If the toilet shifts more than 1/8 inch, reseat it with a new wax ring.

How often should I replace a wax ring?

Only when you pull the toilet — not preventively. A properly-installed wax ring on an anchored toilet lasts 20 to 30 years. Always use a new ring on reinstallation — they cost $5, and you never want to reseat a toilet twice.

The four bathroom-repair techniques worth mastering

1. The leak-isolation test

Turn off the main water supply to the bathroom. Watch the water meter for 15 minutes. If the meter moves, the leak is upstream of the shutoff — a supply line or valve issue. If it holds, the leak is at the fixture. This test distinguishes between a DIY repair and a plumber call in fifteen minutes.

2. The continuity check before any electrical repair

Flip the breaker. Test with a non-contact voltage tester at the device. Test the GFCI with its TEST button and verify downstream outlets lose power. Test at the panel again. This four-step sequence takes two minutes and is the most important safety protocol in bathroom electrical work.

3. The right way to caulk

Two strips of painter's tape, 3/16-inch gap. Single continuous silicone bead at 45 degrees. One pass with a wet finger or caulk tool. Remove tape while wet. Wait 24 hours. The tape removes the skill ceiling; the single pass determines the result.

4. The material decision: putty vs. silicone vs. Teflon tape

Plumber's putty: below-sink fixtures where a flexible waterproof bed is needed. Not for plastic. Silicone caulk: wet surfaces that flex — tub-to-tile seams, shower door frames. Teflon tape: threaded plumbing connections — three wraps clockwise on the male thread. Using the wrong material for the job is how leaks begin.

Cost-to-payback ranking

One more thing — the repair sequence that keeps a bathroom honest

Turn the water off first, fix the leak you can see, find the leak you can't, replace the parts that are still working but old. The toilet flapper that's five years old is cheaper to replace now than after the ghost flushes start. The caulk line that's two years past its service life is cheaper to replace now than after water reaches the subfloor. The wax ring you've never replaced is worth replacing when you pull the toilet for any reason. That's the order. That's the practice. The bathroom that gets this attention once a year stays a bathroom. The bathroom that doesn't becomes a renovation.

About this intersection

This page is the Repair × Bathroom intersection — one of 60 task-lane × room intersection pages on HowTo: Home Edition. It exists at two equivalent URLs by design: /en/repair/bathroom/ (lane-first) and /en/bathroom/repair/ (room-first). Both are real pages with real content; both serve the same purpose; both link to the same 49 leaf-level repair guides. The dual entry points let users navigate the way they think — some readers think "I want to repair something, which room am I in?" while others think "I'm in the bathroom, what can I fix?" — and the site supports both mental models.