Your main water shutoff valve stops water to the whole house in an emergency. A running toilet is almost always a worn flapper or fill valve, and you can usually fix it yourself. A small, steady drip from a fixture is a repair job for a plumber if it involves a wall, ceiling, or the main line. This guide walks through all three, plus what to do in the first few minutes of a leak while you wait for help.
Stop and Call a Professional First for These Situations
Some plumbing problems are not homeowner repairs. Stop and contact a licensed plumber, or your utility in an emergency, if you see or suspect any of the following:
- Water near an electrical outlet, panel, or any powered appliance
- A gas smell near a water heater or gas line
- A burst pipe inside a wall, ceiling, or slab
- Sewage backing up into a sink, tub, or floor drain
- Signs of mold, or a leak that has been active long enough to soak framing or drywall
- Any repair that involves cutting into a wall, altering a main line, or changing a gas connection
These situations call for licensed plumbing, electrical, or hazardous-material professionals. Working near water and electricity together is dangerous, and licensed contractors carry the training and insurance for it. This article covers routine, low-risk homeowner tasks only.
Find Your Main Water Shutoff Valve Now, Before You Need It
The main shutoff valve controls all water entering your home. Finding it before an emergency saves critical minutes.
- Houses: Often near where the water line enters the house — a basement wall, a utility closet, near the water heater, or outside near an exterior wall or the water meter.
- Condos and apartments: There may be a unit-level shutoff, but the main building shutoff is usually controlled by the property manager or building staff. Ask now, not during a leak.
- What it looks like: A round wheel-style handle (turn counterclockwise several full turns to close) or a lever-style ball valve (turn a quarter turn until it sits crosswise to the pipe).
Turn it once, gently, to confirm it works and isn’t seized. If it’s stiff, corroded, or won’t move, have a plumber service it before you actually need it in an emergency.
Fix a Running Toilet
A running or constantly refilling toilet is one of the most common household leaks, and it’s usually safe for a homeowner to check.
- Remove the tank lid and set it somewhere safe.
- Look at the flapper, the rubber piece that seals the drain at the bottom of the tank. If it looks warped, cracked, or isn’t sitting flat, it’s likely not sealing. Flappers are inexpensive and sold to fit most standard toilets.
- Check the chain connecting the flush lever to the flapper. If it’s too tight, it can hold the flapper open slightly. If it’s too loose, it may not lift the flapper at all.
- Look at the fill valve, the taller mechanism usually on the left side of the tank. If water is trickling into the overflow tube even after the tank is full, the fill valve may need adjustment or replacement.
- A simple leak test: put a few drops of food coloring into the tank and wait about ten minutes without flushing. If color shows up in the bowl, the flapper is leaking.
The U.S. Environmental Protection Agency’s WaterSense program notes that the average household can lose over 10,000 gallons of water a year to leaks like this, and toilet leaks are one of the most common sources. Replacing a flapper or fill valve is a basic parts swap most homeowners can do with the water supply turned off at the toilet’s own shutoff valve, usually located on the wall behind or beside the toilet.
When a Drip Needs a Professional
Not every leak is a DIY job. Use this to decide:
Likely safe to handle yourself
- A dripping faucet aerator or showerhead you can unscrew by hand
- A loose supply-line connection under a sink that just needs hand-tightening
- A running toilet, as described above
Call a licensed plumber
- A leak you can hear or see but can’t locate
- Water stains on a ceiling or wall, which usually means the leak is inside a structure
- A leak at a joint, valve, or pipe that requires tools beyond a wrench, or that keeps coming back after a simple fix
- Any leak involving the main line, a water heater connection, or a fixture tied into the home’s rough plumbing
Cost, exact timelines, and whether a permit applies are specific to your plumber, your municipality, and the scope of the repair. Ask your plumber for a written estimate, and check with your local building or permitting office to confirm whether the specific job requires a permit in your area.
Emergency Steps While You Wait for a Plumber
If you have an active leak or burst pipe, acting fast limits the damage.
- Shut off the main water valve first. This stops the source no matter where the leak is.
- If the leak is near an electrical outlet, appliance, or panel, do not touch it. Leave the area and shut off power to that area at the breaker panel if you can do so without stepping in water.
- Move furniture, electronics, and belongings away from the water.
- Soak up standing water with towels or a wet-dry vacuum rated for water pickup, once it’s safe to do so.
- Open a window or run a fan to start drying the area and reduce the chance of mold.
- Take photos of the damage for insurance before cleanup, if it’s safe to do so.
- Call a licensed plumber. If water has reached electrical components or structural framing, also contact a qualified electrician or restoration professional.
Quick Reference Checklist
- Know the location of your main shutoff valve before an emergency happens
- Test the shutoff valve once a year to make sure it still turns
- Check your toilet tank for a worn flapper or fill valve if you notice higher water use
- Never work near standing water and live electrical outlets or panels
- Call a licensed plumber for hidden leaks, main line issues, or anything involving gas or structural work
- Confirm permit and licensing requirements with your local building department before hiring for larger repairs
Cost and Evidence Limits
This article does not include repair costs, project timelines, or specific product recommendations, because these vary by region, home age, and the scope of the problem. For current guidance on finding home repair assistance programs or general consumer information on hiring contractors, USA.gov’s home repair resources are a good starting point. Always verify permit and licensing rules with your local building or code enforcement office, since these requirements are set locally and change over time.
Frequently Asked Questions
How do I know if my toilet is running even when it sounds quiet?
Use the food coloring test described above. A silent leak can still waste a significant amount of water without making noise.
Is it safe to shut off my main water valve myself?
Yes. Turning a shutoff valve off and back on is a normal homeowner task. If the valve is stuck, corroded, or leaking when you try to turn it, stop and call a plumber to service or replace it.
Can I fix a leaking pipe with tape or a repair clamp myself?
Tape and pipe clamps are sold as temporary measures to slow a leak, not permanent fixes. Use them only to reduce damage while you wait for a licensed plumber, not as a long-term solution.
Do I need a permit to replace a toilet flapper or fix a running toilet?
Basic parts replacement inside a toilet tank is routine maintenance and generally does not require a permit, but permit and code rules are set locally. Check with your local building department if you’re unsure, especially for any larger plumbing work.
Safety Disclaimer
This article provides general, educational information for homeowners and renters. It is not a substitute for professional inspection or repair. Water and electricity are a dangerous combination — never work on plumbing near an energized outlet, appliance, or panel.
Structural, gas, and main-line plumbing work should be handled by a licensed professional. Permit, code, and licensing requirements vary by state and municipality; confirm current rules with your local building or code enforcement authority before starting any project. See our full project safety disclaimer for more on when to stop and call a professional.
To see how we verify facts like the ones in this article, visit our sources and methodology page and our editorial standards.