Many plumbing problems announce themselves with a handful of symptoms, and some can be checked safely at home before anyone is called. The troubleshooter below asks two or three questions about a symptom and points to the likely cause, a check that is safe to make and the service that usually resolves it.
Symptom Troubleshooter
Choose a symptom, answer the questions and press Show Likely Cause.
The troubleshooter needs JavaScript. The quick checks and the table below cover the same symptoms.
Quick Checks by Symptom
No Hot Water
- Electric heater: check the breaker in the panel. Do not open the heater’s access covers.
- Gas heater: look through the sight glass for the pilot; relight only by the label’s instructions.
- Tankless: note any error code on the display and check that the gas to other appliances is on.
Low Water Pressure
- Unscrew and rinse the faucet aerator or soak the showerhead.
- Make sure the main shutoff and the fixture valves are fully open.
Slow Drain
- Clean the sink stopper or the tub’s hair catcher.
- Use a plunger with the overflow opening covered. Skip chemical openers.
Running Toilet
- Add a few drops of food coloring to the tank; color in the bowl after 15 minutes means a leaking flapper.
- Check whether the float sets the water above the overflow tube, and lower it if so.
Dripping Faucet
- Close the supply valves under the sink to stop the drip until it is repaired.
- Note the brand if it is on the faucet; cartridges are specific to the maker.
Water Stain
- Mark the edge of the stain with a pencil and check it again in a day.
- Run the meter check with every fixture off.
Stop and Call a Plumber
- Any smell of gas: leave the house first, then call 911 and the gas company
- Water coming through a ceiling, or a ceiling that sags
- Sewage in a tub, shower or floor drain
- Water at the base of a water heater, or a relief valve discharging
- A water meter that moves with every fixture off
- Several drains slowing or backing up at once
- A shutoff valve that will not close
For anything spreading now, the Emergency Plumbing page lists the first steps.
Common Fixture Problems
More columns to the right: swipe.
| Fixture | Symptom | Simple check | When to call |
|---|---|---|---|
| Kitchen sink | Slow drain or standing water | Run the disposal; check the dishwasher drain hose loop | Water backs up into the other basin or the dishwasher |
| Bathroom sink | Slow drain | Remove and clean the pop-up stopper | Still slow after the stopper is clean |
| Toilet | Runs or refills on its own | Food coloring in the tank: color in the bowl means a leaking flapper | It leaks at the base or rocks on the floor |
| Shower | Low flow | Soak the showerhead in vinegar to remove scale | Low flow at every fixture, not only the shower |
| Water heater | No hot water | Check the breaker or the pilot as the label instructs | Water at the base, a gas smell or a relief valve discharging |
| Hose bib | Drips with the handle closed | Close firmly by hand; check the vacuum breaker cap | Water inside the wall behind it |
Low Pressure and High Water Bills
Why is the water pressure low throughout the house?
The common causes are a partly closed main shutoff, a failing pressure regulator where the line enters the house, galvanized supply pipe narrowed by rust, or a leak drawing water away. A pressure gauge on a hose bib shows the house pressure in a minute; anything well below the usual range points to the regulator or the supply, and a sudden drop with no other change is worth a meter check for a leak.
Why is the water bill suddenly high?
A running toilet is the most common cause and is often silent. After that come irrigation leaks, a dripping faucet left for months, and hidden leaks in walls or under the slab. The meter check on the Leak Repair page tells a hidden leak apart from heavy use.
Is it safe to relight a water heater pilot?
On most gas tank heaters, yes, by following the instructions on the label exactly. If there is a smell of gas, do not relight anything: leave the house and call 911 and the gas company from outside.
Book a Plumbing Appointment
When a check does not solve the problem, a short description of what was tried saves time on the visit.