Plumbing you can do yourself, and when to call a plumber

Updated November 10, 2026 · KeystoneProGuide editorial team

What plumbing can a homeowner safely do?

Quite a lot of the small stuff. The EPA's WaterSense program describes the most common household leaks, worn toilet flappers, dripping faucets and other leaking valves, as often easy to fix with a few tools and parts that pay for themselves in water saved. Checks such as reading the meter, testing a toilet with food coloring and finding the shut-off valve need no tools at all. The line comes where the work involves new or moved piping, gas, or anything a permit covers.

Which small repairs do agencies describe for homeowners?

Replacing a toilet flapper. The EPA says flappers should be checked periodically and replaced at least every five years, and calls replacing one quick and easy. Take the old flapper, or a photo of it, to the store so the new one fits.
Fixing a dripping faucet. The EPA says worn washers and gaskets frequently cause faucet drips, and that a faucet dripping once a second can waste more than 3,000 gallons a year. Its first tip: turn off the water line before you start.
Sealing a leaky showerhead. Some leaks stop with a tight connection and pipe tape on the threads, according to the EPA. A shower valve that drips when it is off is a different matter; the EPA suggests an experienced handyperson or a licensed plumber.
Replacing a hose washer. If a garden hose leaks at the spigot, the EPA suggests a new washer and a tight connection with pipe tape.
Cleaning faucet aerators. The Philadelphia Water Department says aerators can trap lead and release it later, and suggests taking them apart, soaking them in vinegar and scrubbing them with an old toothbrush.

What checks can you do without any repair?

The meter test. Read the water meter, use no water for two hours, and read it again. The EPA says any change probably means a leak.
The toilet dye test. A few drops of food coloring in the tank; color in the bowl after 10 minutes means a leak.
Finding the shut-off. The Philadelphia Water Department says shut-off valves are usually near the water meter, and that in an emergency you should use the house-side valve. Find yours before you need it.
Setting the water heater. The Consumer Product Safety Commission says the temperature can be set to 120 degrees Fahrenheit or lower to prevent burns.
Flushing the pipes. If you are concerned about lead, the EPA suggests running the tap, showering or doing laundry before drinking water that has sat in the pipes, and using only cold water for drinking and cooking.

Can you thaw a frozen pipe yourself?

Yes, carefully. The American Red Cross says to keep the faucet open and apply heat with an electric heating pad, a hair dryer, a space heater kept away from anything flammable, or towels soaked in hot water, and never a blowtorch, kerosene or propane heater, or other open flame. If you cannot find the frozen section, cannot reach it or cannot thaw it, it says to call a licensed plumber. If the pipe has already split, shut off the water first.

What about clogged drains?

Mechanical methods first. The EPA's advice for septic homes is to avoid chemical drain openers and use boiling water or a drain snake instead, and never to pour cooking oil or grease down the drain. The same EPA page says to flush nothing but human waste and toilet paper, which rules out wipes, paper towels and feminine products.

What should you leave to a licensed plumber?

Anything that needs a permit. Pennsylvania's construction code says an ordinary repair needs no permit, but adding to or relocating water supply, sewer, drainage, waste or vent piping is not an ordinary repair. Your municipality decides how that applies, and whether a homeowner may file for a permit on their own house.
Most permitted work in Philadelphia. The city says a licensed master plumber must oversee plumbing work done under a permit, and that backflow devices must be installed by an approved technician. Repairs with the same material, resetting a toilet without moving pipes, and clearing stoppages need no permit there.
Gas water heaters. The CPSC says most appliances should be installed by qualified professionals and that malfunctioning fuel-burning appliances, water heaters among them, are a source of carbon monoxide.
A water heater's safety parts. The residential code's commentary explains that stored hot water is under pressure and that tanks must be protected against explosion by relief valves. The code then sets 14 rules for the valve's discharge pipe, from its size and slope to where it ends.
Pipes outside the house. In Philadelphia, the city says owners are responsible for the water and sewer pipes under the sidewalk and street, and that repairing a defect requires a licensed plumber.

How do you know when a DIY fix has failed?

Run the meter test again after the repair. If the meter still moves with everything off, the leak is somewhere you have not found. Signs you need a plumber lists the warnings to watch for, the Pennsylvania rules guide explains licensing and permits, and licensed plumbers are on the plumbers directory page.

Sources

Fix a Leak Week, U.S. Environmental Protection Agency (WaterSense)
Residential Toilets, U.S. Environmental Protection Agency (WaterSense)
All About Frozen Pipes, Philadelphia Water Department
Lead Plumbing & Water Quality, Philadelphia Water Department
Basic Information about Lead in Drinking Water, U.S. Environmental Protection Agency
Childproofing Your Home, U.S. Consumer Product Safety Commission
Preventing & Thawing Frozen Pipes, American Red Cross
How to Care for Your Septic System, U.S. Environmental Protection Agency
Get a Plumbing Permit, City of Philadelphia
34 Pa. Code § 403.62. Permit requirements and exemptions., Commonwealth of Pennsylvania (Pennsylvania Code)
Carbon Monoxide Fact Sheet, U.S. Consumer Product Safety Commission
Chapter 28 Water Heaters, 2021 International Residential Code, International Code Council
Follow these tips to get ready for pipe repairs, City of Philadelphia, Department of Revenue