Before You Call a Plumber
A few questions about what you are seeing, then a straight answer: fix it yourself (with the steps), or call a pro (and what to tell them).
Question 1
What is going on?
Every answer at a glance
You can likely fix this yourself
Replace the cartridge or washer
A dripping spout is almost always a worn cartridge, washer or O-ring. Parts cost a few dollars and the job takes under an hour.
Faucet and sink installation cheat sheetYou can likely fix this yourself
Tighten or replace the supply line
Try a quarter turn on the compression nut first. If the braided line itself is weeping or more than about 5 years old, replace it: they are cheap and a burst line floods fast.
PEX and supply sizing cheat sheetYou can likely fix this yourself
Reseat the P-trap
Plastic slip-joint traps loosen and their washers flatten. Hand-tightening or a new washer fixes most of them.
Plumbing cheat sheetDIY if you are comfortable, otherwise call
Replace the wax ring
Water at the base after flushing usually means a failed wax ring. It is a common DIY job, but it means lifting the toilet. If the floor feels soft, call a pro: the subfloor may be rotted.
Toilet installation cheat sheetCall a plumber
Call a plumber, and keep the main off
Hidden leaks need the wall or ceiling opened and the source found before the repair. Keep the main shut, photograph the damage for insurance, and get water out of drywall and insulation quickly to limit mold.
DIY if you are comfortable, otherwise call
Patch it now, repair it properly soon
A push-to-connect repair coupling or a pipe repair clamp will stop a pinhole on an exposed copper or PEX line. Treat it as a temporary fix if the pipe is corroded, and have the run looked at.
PEX sizing cheat sheetAct now
Call an emergency plumber and protect the house
If no valve stops the water, call your water utility (they can shut the street valve) and an emergency plumber. Turn off electricity to any area where water is reaching outlets or fixtures.
You can likely fix this yourself
Pull the hair clog
Bathroom clogs are hair and soap a few inches down. A plastic barbed drain tool clears most of them in minutes. Skip chemical drain cleaners: they damage older pipes and make the next repair dangerous.
You can likely fix this yourself
Clear the trap, then snake it
Kitchen clogs are grease and food. Pull and clean the P-trap first; if the clog is past it, a 25 ft hand auger reaches most of the branch line.
Garbage disposal cheat sheetYou can likely fix this yourself
Flange plunger, then a closet auger
Use a flange (bell) plunger with a good seal and 15 to 20 firm strokes. If that fails, a closet auger reaches the trapway without scratching the bowl.
Toilet installation cheat sheetCall a plumber
Likely a main line clog: call a plumber
Several slow drains, or water coming up in the lowest drain, point to the main sewer line (roots, a belly, or a collapse). Stop running water and call a plumber with a camera and a machine auger.
You can likely fix this yourself
Replace the flapper or fill valve
A toilet that runs is leaking tank water into the bowl (flapper) or overfilling into the overflow tube (fill valve). Both are universal parts and a 20 minute fix.
Toilet installation cheat sheetYou can likely fix this yourself
Check the water level and rim jets
Set the tank water about an inch below the top of the overflow tube, make sure the flapper chain has a little slack, and clear mineral buildup from the rim holes with a wire.
DIY if you are comfortable, otherwise call
Check the pilot, then call if it will not stay lit
Follow the relight instructions on the tank label. If the pilot will not stay lit, the thermocouple or gas control may have failed. If you smell gas at any point, leave the house and call the gas utility.
Water heater cheat sheetDIY if you are comfortable, otherwise call
Check the breaker and the high-limit reset
Check for a tripped breaker, then the red reset button behind the upper access panel (power off first). If it trips again, an element or thermostat has failed: replaceable DIY with a multimeter, or call.
Water heater cheat sheetCall a plumber
A leaking tank needs replacing
Water from the tank body means the tank has rusted through, which cannot be repaired. Shut the cold supply and the power or gas, and get quotes for a replacement. Water from a fitting or the relief valve line may be a smaller fix.
Water heater cheat sheetYou can likely fix this yourself
Clean the aerator or shower head
Unscrew the aerator or shower head and soak it in vinegar overnight to dissolve mineral buildup. If it is a single-handle faucet, the cartridge may also be clogged.
DIY if you are comfortable, otherwise call
Check the main valve and the pressure regulator
Make sure the main shutoff is fully open. A pressure gauge on a hose bib should read roughly 40 to 80 psi. If it is low and you have a pressure reducing valve, it may need adjusting or replacing. Ask your neighbors too: if they are low, call the water utility.
PEX flow rate cheat sheetYou can likely fix this yourself
Refill the dry trap
Unused floor drains, guest showers and basement sinks lose the water seal in their trap. Run water for a minute and pour in a little mineral oil to slow evaporation.
DIY if you are comfortable, otherwise call
Check the vents
A blocked roof vent, a failed air admittance valve or a vent that is too small can siphon traps dry and let sewer gas in. Air admittance valves are an easy swap; roof vents and vent sizing are a job for a plumber.
Plumbing vent size chart