What to Do Before Calling a Plumber for a Leak
This guide is for general homeowner education. For safety-sensitive repairs or active damage, contact a licensed professional.
Quick answer
Shut off the water at the nearest valve (or the main if you can't isolate it), move belongings out of the way, lift any standing water with towels, take photos and videos, and write down everything you noticed — when it started, where it's coming from, and any sounds or smells. Don't open walls or attempt major repairs.
When a leak appears, the first 30 minutes matter more than the next 24. A few simple steps protect your home, give your plumber a head start, and often save hundreds of dollars in damage. Here's exactly what to do.
Shut off the water
Find the closest shut-off valve to the leak.
- Under-sink leak: turn the small valve under the sink clockwise until it stops
- Toilet leak: turn the small valve behind the toilet clockwise
- Water heater leak: shut off the cold supply valve at the top of the tank
- Appliance leak: shut off the supply behind the appliance
- Can't isolate it: shut off the main water valve where the line enters the home
Know where your main shut-off is
Walk your home now and locate the main shut-off valve. In an emergency, you don't want to be searching with water spreading.
Identify where the leak appears to be coming from
- Look up — water often travels along joists before dripping
- Check the obvious sources first (sink supply, toilet, appliance)
- Note whether the leak is constant or only happens when water runs
- Listen for hissing, dripping, or running water
Protect floors and belongings
- Move rugs, furniture, electronics, and stored items out of the wet area
- Lift visible standing water with towels or a wet/dry vacuum
- Place a bucket or container under any active drip
- Open windows or run fans to start moving air
- Turn off power to wet areas at the breaker if water is near outlets
Take photos and videos
Document everything before you start mopping. Photos and videos help with insurance claims, give your plumber a remote preview, and create a record in case the issue resurfaces later.
What to avoid doing yourself
- Don't open walls or ceilings to chase the leak
- Don't disassemble valves or supply lines unless you're confident
- Don't pour chemicals down drains
- Don't use an electric shop vac near energized wiring
- Don't ignore a sewer smell — it can indicate a serious issue
Information to give the plumber
- When the leak started
- What you were doing or what was running at the time
- Where the water appears to be coming from
- Whether it's continuous or intermittent
- Any unusual sounds, smells, or recent plumbing work
- Photos and videos you've taken
Recommended tools to have ready
- Towels and a wet/dry vacuum
- 5-gallon bucket
- Flashlight
- Phone or camera for documentation
- Adjustable wrench (in case the plumber needs an extra hand)
- Leak detector to install once the leak is fixed
Emergency signs — call immediately
- Water entering electrical outlets, fixtures, or panels
- Sewage backing up into the home
- Water actively coming through ceilings or walls
- Sudden loss of all water pressure or no water at all
- Smell of gas
- Frozen, bulging, or split pipes in winter
When to call a professional
Call a licensed plumber for any leak that you can't fully isolate, any leak inside a wall or ceiling, anything involving the main water line or sewer, gas-line concerns, and water near electrical components. Many plumbers offer 24/7 emergency service — don't wait until business hours if water is actively running.
Frequently asked questions
Should I shut off the main water valve for any leak?+
Not always. If you can isolate it at a closer valve (under the sink, behind the toilet), do that first. Use the main only if you can't stop the leak otherwise.
How do I find my home's main water shut-off?+
Usually in the basement, garage, crawlspace, or near the water meter outside. Look near the front of the home along the wall facing the street.
Do plumbers charge more for emergency calls?+
Yes — emergency or after-hours calls often run 1.5–2x normal rates. Knowing how to shut off water yourself is the cheapest emergency tool you have.
Should I take photos before mopping up?+
Yes. Photos and videos help with insurance claims and give the plumber a clear picture of what they're walking into.
Can I install a leak detector myself afterward?+
Most basic and smart leak detectors are plug-and-play — see our guide on best leak detectors for under sinks, water heaters, and appliances.
Related articles
How Much Does It Cost to Fix a Leaky Toilet?
Typical plumber pricing for the most common toilet leaks, plus DIY-friendly fixes you can handle yourself.
Leak Detectors for Under Sinks, Water Heaters, and Appliances: What to Look For
Inexpensive leak detectors that can save you thousands by catching slow leaks early.
What to Do If Water Gets Under Vinyl Plank Flooring
Vinyl plank is waterproof on top, but the seams and subfloor are not. Here's a calm, step-by-step plan for drying, inspecting, and deciding whether the planks need to come up.
How Much Does Water Damage Repair Cost?
A broad cost guide for water damage repair — from a small leak to a full remediation project.