12 Common Residential Plumbing Issues (and How to Fix Them)
Every homeowner meets the same cast of common plumbing problems sooner or later: the faucet that will not stop dripping, the toilet that runs all night, the drain that slows to a crawl. Most of these issues are diagnosable in minutes and many are fixable with basic tools — but knowing which is which saves you from both ignoring a serious problem and overpaying for a trivial one. Below are the 12 most common residential plumbing issues, what causes each, and what to do about it.
1. Dripping Faucets
A faucet dripping once per second wastes over 3,000 gallons a year — and the fix is usually a $5 to $15 cartridge or O-ring, not a new faucet. Nearly all modern drips come from a worn cartridge (single-handle faucets) or a worn washer/seat (older two-handle faucets).
Quick diagnosis: Turn off the water under the sink, remove the handle and cartridge, and take the old part to the store for an exact match. Twenty minutes and most drips are history. If the faucet body itself is corroded or the brand is unidentifiable, replacement makes more sense — see our faucet and fixture guides for installed costs.
2. Running Toilets
A toilet that runs constantly can waste 200+ gallons a day — you will see it on the water bill before you hear it. The culprit is almost always the flapper (the rubber seal at the tank bottom) or the fill valve.
Quick diagnosis: Drop food coloring in the tank and wait 15 minutes without flushing. Color in the bowl means the flapper leaks — replace it ($10). If water runs into the overflow tube, the fill valve needs adjusting or replacing ($15). Our 10-minute running toilet fix walks through the sequence.
3. Clogged Drains
Kitchen sinks clog from grease and food; bathroom drains clog from hair and soap scum. One slow fixture is a local clog; every drain in the house slowing at once points to the main sewer line — a very different (and pricier) problem.
Quick diagnosis: Try a plunger first, then a drain snake ($25 tool that pays for itself immediately). Skip chemical drain cleaners for real blockages — they rarely clear them and can damage pipes. If multiple fixtures back up together, read our drain cleaning guides and consider a camera inspection before paying for repeated cleanings.
4. Low Water Pressure
Low pressure is a symptom, not a disease. One weak fixture usually means a clogged aerator or showerhead (unscrew, soak in vinegar, done). Whole-house low pressure points to a failing pressure regulator, partially closed main valve, or corroded supply lines.
Quick diagnosis: Screw a $10 pressure gauge onto a hose bib. Normal residential pressure is 40–80 psi. Below 40 with the main valve fully open means something upstream needs attention — our water pressure guides walk through the full diagnostic order.
5. Leaky Pipes
Pipe leaks range from a weeping joint you spot during a basement walkthrough to a burst supply line spraying the cabinet. Supply-side leaks (pressurized) demand immediate action; drain-side leaks (gravity) are slower but still rot wood and breed mold.
Quick diagnosis: For supply leaks, shut the nearest valve or the main, then assess. Small pinholes in copper can be patched temporarily with epoxy or a repair clamp; cracked drain pipe gets cut out and replaced with couplings. Our leaky pipe repair guide covers temporary and permanent fixes by pipe material.
6. Water Heater Problems
No hot water, lukewarm showers, rumbling noises, or rusty water — water heater complaints cluster around a few causes. Rumbling usually means sediment buildup (flush the tank yearly). No hot water on a gas unit often means a failed thermocouple or pilot issue; on electric, a tripped breaker or dead heating element.
Quick diagnosis: Check the unit's age first — past 10–12 years for a tank model, replacement usually beats repair, especially if the tank itself leaks (tank leaks are never repairable). See our water heater guides for replacement costs and the repair-vs-replace decision.
7. Slow Draining Sinks and Tubs
A drain that is slow but not fully blocked is in the early stage of a clog — the best time to act. Bathroom sinks and tubs slow from hair and soap; kitchen sinks from grease narrowing the pipe.
Quick diagnosis: Remove and clean the stopper and pop-up assembly (most of the gunk lives there), then snake if needed. If the tub and the toilet both drain slowly, suspect a venting problem or a developing main-line blockage rather than a local clog.
8. Gurgling Drains
Gurgling means air is being pulled through the trap — usually a venting problem or a partial blockage downstream. A single gurgling sink after heavy use is often minor; a toilet that gurgles when the washer drains suggests a vent or main-line issue.
Quick diagnosis: Check whether the fixture still drains at normal speed. Normal speed plus gurgling often means a blocked vent stack (debris, bird nest) — sometimes clearable from the roof with a garden hose. Slow plus gurgling means a downstream restriction. Details in our drain gurgling guide.
9. Sewer Smells Indoors
Sewer gas smells like rotten eggs and should never be ignored — besides the odor, it can carry methane and hydrogen sulfide. The most common cause is a dry P-trap in a rarely used drain (guest bathroom, floor drain); running water for 30 seconds refills it.
Quick diagnosis: If the smell is at one drain, run water and see if it clears. Persistent whole-house odor, or odor plus slow drains, can mean a broken vent, a cracked sewer line, or a failed wax ring under a toilet — all pro territory. Our sewer line guides cover the serious end of this symptom.
10. Burst and Frozen Pipes
Frozen pipes burst not where the ice forms but downstream of it, where pressure builds — and the flooding happens when the ice thaws. The average insurance claim runs into five figures, almost all water damage rather than pipe repair.
Quick diagnosis: No water from a faucet in freezing weather means a frozen line — open the faucet and apply gentle heat (hair dryer, never a torch) working back from the faucet. If a pipe has already burst, shut the main immediately. Prevention (insulation, dripping faucets, 55°F minimum) costs almost nothing — see our frozen pipe guides.
11. Sump Pump Failure
Sump pumps fail in exactly two ways that matter: they don't turn on when water rises (stuck float, dead motor, tripped breaker) or they run but can't keep up (undersized, clogged discharge). Either way you discover it during the storm.
Quick diagnosis: Pour a bucket of water in the pit twice a year — the pump should kick on, pump down, and shut off. Add a battery backup if you don't have one; storms that flood basements also kill power. Our sump pump guides cover types and costs.
12. Unexplained High Water Bills
A sudden bill spike with no change in habits almost always means a leak — running toilet, dripping irrigation, or a hidden supply leak. The water meter test settles it: turn off everything in the house, note the meter, wait an hour without using water, and check again. Movement means a leak.
Quick diagnosis: Check toilets with the dye test and look at the irrigation system first (the two most common culprits). If the meter moves and nothing is visible, you likely have a hidden or underground leak — our leak detection guides explain how pros pinpoint it.
When to Call a Professional
DIY ends where these begin: anything involving the main sewer line, gas lines, leaks inside walls or under slabs you can't locate, and any project requiring a permit. A good rule — if the fix requires opening a wall, touching gas, or you can't identify the source after basic diagnosis, call a licensed plumber. For cost expectations on any of these jobs, browse our plumbing cost guides before you pick up the phone.