10 Most Common Plumbing Problems and How to Fix Them

Plumbing problems have a habit of appearing at the worst possible moment — a dripping faucet at 2 a.m., a clogged drain minutes before guests arrive, or a running toilet you've been ignoring for weeks. The good news is that most common plumbing problems have straightforward causes, and many can be fixed by a confident homeowner with basic tools. The key is knowing which problems you can tackle yourself and which ones demand a licensed professional before they escalate into costly damage.

This guide walks through the 10 most common plumbing problems US homeowners face, explaining what causes each one, how to fix it yourself where possible, and when it's time to stop and call a plumber.

1. Dripping Faucets

What causes it: A dripping faucet is almost always caused by a worn washer, O-ring, or cartridge inside the faucet valve. Every time you use the tap, that internal component compresses against a valve seat — over time it wears out and water seeps through even when the handle is fully closed. Corrosion on the valve seat itself can also cause dripping.

DIY fix: Turn off the water supply valve under the sink, remove the faucet handle (usually one screw under a decorative cap), and replace the worn washer or cartridge. For ball-type faucets, replacement kits are available at any hardware store for under $20. The whole job typically takes 30–60 minutes. Don't ignore a dripping faucet — a faucet dripping once per second wastes over 3,000 gallons of water per year.

When to call a plumber: If you've replaced the internal components but the dripping continues, the valve seat itself may be damaged or corroded. Resurfacing or replacing a valve seat requires a special tool and, in many cases, professional diagnosis. Also call a plumber if the faucet handle is stiff, the leak is coming from the base of the spout, or the fixture is older than 20 years and the internal parts are no longer available.

2. Slow Draining Sink

What causes it: Bathroom sinks slow down because of hair, soap scum, and toothpaste buildup accumulating around the stopper and inside the drain pipe. Kitchen sinks clog from grease, food particles, and cooking fat that solidifies on the pipe walls over time.

DIY fix: Start with the simplest approach — remove the drain stopper (usually it just twists or lifts out) and clean it by hand. Pour boiling water down the drain to dissolve grease. For stubborn blockages, use a drain snake or a baking soda and white vinegar flush (pour half a cup of baking soda followed by half a cup of white vinegar, let it fizz for 15 minutes, then flush with hot water). Avoid chemical drain cleaners — they can damage older pipes and rarely solve the underlying problem.

When to call a plumber: If multiple sinks drain slowly at the same time, the blockage is likely deeper in the main drain line rather than the individual fixture. This needs professional hydro-jetting or auger equipment. Also call a plumber if DIY efforts haven't worked after two attempts, as persistent blockages can indicate a venting issue or partial pipe collapse.

3. Clogged Bath or Shower Drain

What causes it: Hair is the primary culprit in shower and bath drains — it binds with soap residue and builds up quickly into a dense mat that blocks water flow. Even small amounts of hair shed daily can create a serious blockage within weeks if there's no drain guard in place.

DIY fix: A pair of needle-nose pliers or a purpose-made hair removal tool (a flexible plastic strip with barbs, available for under $5) can pull out the hair clog manually — it's unpleasant but effective. For deeper blockages, a small hand-powered drain snake will do the job. Once cleared, install a mesh drain cover to catch hair before it enters the drain pipe. Clean it weekly — it takes ten seconds and prevents future blockages entirely.

4. Clogged Toilet

What causes it: The most common cause is flushing items that don't break down in water — excessive toilet paper, wet wipes (even those labeled "flushable"), cotton balls, paper towels, or hygiene products. In homes with young children, toys and other foreign objects are frequently to blame.

DIY fix: A flange plunger (the kind with an extended rubber flap that creates a seal inside the toilet bowl) is far more effective than a flat cup plunger for toilets. Seal the flange into the drain opening, push down slowly, then pull up sharply to create suction. Repeat 10–15 times. If the plunger fails, a toilet auger (closet snake) extends further into the trap and can hook or break up deeper blockages. Use gentle pressure — forcing a snake too hard can scratch the porcelain.

When to call a plumber: If the toilet overflows despite plunging, or if multiple toilets or drains in the house are backing up simultaneously, you likely have a main sewer line blockage. This is always a job for a licensed plumber with professional equipment.

5. Running Toilet

What causes it: A toilet that runs constantly (you can hear water filling indefinitely) usually has one of three problems: a worn flapper that no longer seals the flush valve, a float set too high so water constantly overflows into the overflow tube, or a faulty fill valve that doesn't shut off when the tank is full. A running toilet wastes up to 200 gallons of water per day — roughly 6,000 gallons per month added to your water bill.

DIY fix: Remove the tank lid and observe the fill cycle. If water is draining into the overflow tube, the float needs to be adjusted lower — on ball float systems, bend the arm downward; on cup float systems, turn the adjustment screw counterclockwise. If the flapper is the culprit (you can confirm by pressing down on it — if the running stops, that's your issue), replacement flappers cost under $10 and install in minutes. Full fill valve replacement kits are available for $15–$25 and come with clear instructions.

When to call a plumber: If replacing the flapper and fill valve doesn't stop the running, there may be a cracked flush valve seat that requires the internal toilet mechanism or even the toilet to be replaced. A plumber can diagnose this quickly.

6. Low Water Pressure

What causes it: Low water pressure at a single fixture is almost always due to a clogged aerator or showerhead — mineral deposits from hard water build up over time and restrict flow. If low pressure affects the whole house, the causes are more serious: a partially closed shut-off valve, corroded supply pipes, a failing pressure regulator, or a leak somewhere in the main supply line.

DIY fix: For a single faucet, unscrew the aerator (the small screen at the tip of the spout) and soak it in white vinegar overnight to dissolve mineral deposits. Rinse and reinstall. For showerheads, remove the head and soak it in a bag of vinegar tied around it for several hours. This restores full flow in the majority of cases.

When to call a plumber: If low pressure affects multiple fixtures or the whole house, do not attempt to adjust the pressure regulator yourself — an incorrectly set regulator can damage appliances and plumbing fixtures. A plumber can test your line pressure with a gauge, identify whether the regulator needs replacement (typical cost: $200–$400), and check for hidden leaks that may be stealing pressure from the system.

7. Leaking Pipes

What causes it: Pipe leaks occur at joints and connections due to wear, loose fittings, or corrosion. They also develop from high water pressure, physical damage, or pipes that have begun to corrode from the inside — particularly in older homes with galvanized steel or polybutylene pipes. Leaks inside walls or under slabs are especially dangerous because they cause structural damage and mold growth before they're discovered.

DIY fix: For minor, accessible leaks at a joint, turning off the water supply and tightening the fitting or wrapping the joint with self-fusing silicone tape provides a temporary repair. Pipe repair clamps from a hardware store can hold a hairline crack in a straight section of pipe temporarily. These are not permanent solutions — they buy you time until a plumber can make a proper repair.

When to call a plumber: Any leak inside a wall, ceiling, floor, or under a slab requires a licensed plumber immediately. Water damage compounds rapidly — within 24–48 hours, mold begins to grow. Signs of a hidden leak include unexplained increases in your water bill, damp spots on walls or ceilings, a musty smell, or the sound of running water when all taps are off.

8. No Hot Water

What causes it: For gas water heaters, the most common culprits are a pilot light that has gone out, a faulty thermocouple (the safety sensor that keeps the pilot lit), or a burner assembly that has failed. For electric water heaters, a tripped circuit breaker or a burned-out heating element is usually responsible. Sediment buildup at the bottom of the tank — especially in areas with hard water — can also dramatically reduce the unit's efficiency and output.

DIY fix: For a gas heater, check whether the pilot light is lit by following the relighting instructions on the unit's label — this is usually a safe DIY step. For an electric heater, check your circuit breaker first. If a breaker has tripped, reset it and wait 30–60 minutes for the water to reheat. Annual flushing of the tank (attaching a garden hose to the drain valve and draining sediment) can extend water heater life significantly and is a straightforward maintenance task.

When to call a plumber: If the pilot won't stay lit after relighting, the thermocouple likely needs replacing — a relatively inexpensive repair but one best left to a licensed plumber or gas technician. If your water heater is over 10–12 years old and producing less hot water, it may be near the end of its service life. A plumber can assess whether repair or replacement makes more financial sense.

9. Jammed Garbage Disposal

What causes it: Garbage disposals jam when an object that shouldn't be in the unit — a bone, a fruit pit, a piece of cutlery, or a buildup of fibrous material like celery strings or artichoke leaves — gets caught between the impeller blades and the grinding ring, preventing the motor from turning.

DIY fix: First and most importantly: never put your hand inside the disposal. Turn the unit off at the wall switch before doing anything else. Most disposals have a reset button on the bottom of the unit — press it after the jam is cleared. To clear the jam, use the hex key (Allen wrench) that came with the unit — insert it into the hex socket on the underside of the disposal and manually turn the grinding plate back and forth to free whatever is jamming it. If you don't have the original hex key, a 1/4-inch Allen wrench works on most brands. Once the plate moves freely, use tongs or pliers to remove the object from inside the unit, then press the reset button and restore power.

10. Sewer System Backup

What causes it: A sewer backup occurs when the main sewer line — the pipe carrying all wastewater from your home to the municipal system — becomes blocked or damaged. Common causes include tree root intrusion (roots are drawn to the warmth and moisture of sewer lines and will crack through them over time), a buildup of grease, debris, and non-flushable items, pipe collapse due to age or ground movement, or a blockage in the city main that backs up into your line.

When to call a plumber — always: A sewer backup is never a DIY situation. The signs are unmistakable: multiple drains backing up simultaneously, sewage smell coming from drains or toilets, water backing up into a tub or shower when you flush the toilet, or gurgling sounds from multiple fixtures. Stop using all water immediately and call a licensed plumber with sewer camera and hydro-jetting capabilities. Sewage contains bacteria and pathogens — do not attempt to clean contaminated areas without proper protective equipment. Raw sewage backup is also a homeowner's insurance event, so document everything and contact your insurer.

Quick Reference: DIY or Call a Plumber?

Use this table as your at-a-glance guide to decide how urgently each common problem needs professional attention.

Preventing Common Plumbing Problems

Most of the problems on this list are either preventable or caught early through simple habits. Install mesh drain covers on all shower and bath drains. Never pour cooking grease down the kitchen sink — let it solidify in a container and dispose of it in the trash. Only flush toilet paper (nothing else). Have your water heater flushed annually. And every six to twelve months, do a walk-through of your home checking under sink cabinets, around the base of toilets, and along exposed pipes for any damp spots or early signs of corrosion. Small problems caught early stay small — ignored, they become expensive emergencies.