Certified Building Contractor CBC1265305 · Plumbing
What does it mean when I hear running water but nothing is on?
A straight answer from a Florida state-certified contractor — then what you can check yourself and when to call. Free estimate: (954) 620-7812.
It usually means water is moving somewhere it shouldn't be: a toilet leaking into the bowl, a fixture or valve that isn't fully closed, or a leak in a supply line in a wall, ceiling or under the slab. Occasionally the sound is harmless, such as a water heater refilling or an ice maker or irrigation system cycling.
The nuance is whether the sound stops when you close the main water shutoff. If it does, the water is moving through your supply plumbing and is worth tracking down. If it keeps going, the sound is probably coming from a drain line or from outside the house, and a different set of causes applies.
Why it happens
The most common source is a toilet. A worn flapper or fill valve lets water trickle into the bowl or overflow tube, which sounds like a faint hiss or an occasional refill. Dripping faucets, a stuck shower valve, and appliance hookups like an ice maker, dishwasher or washing machine can make similar noises.
A hidden leak is the one worth taking seriously. A pinhole in a supply line, a failing fitting, or an aging pipe can hiss or trickle inside a wall or ceiling. In homes with slab-on-grade floors, a leak in a line under the concrete can sound like faint running water, sometimes with a warm spot on the floor. Older homes with polybutylene or galvanized supply lines may be more prone to these failures as the pipe ages. Cast-iron drains in older South Florida homes can also deteriorate and leak, and a leak there can sound like trickling after the house has gone quiet.
Not every sound is a problem. A tank water heater refills after hot water is used, and pressure changes in the supply can make pipes tick or gurgle. During hurricane-season rain, water running through downspouts, exterior drains or a backed-up line can also be heard inside. If the sound is short and tied to a clear event, it is probably normal.
What you can check yourself
Close the main shutoff
With every fixture off, close the main water valve and listen. If the sound stops, the water is in your supply plumbing. If it continues, it is likely a drain, an outside source, or something unrelated to your supply.
Read the water meter
With everything off, look at the meter's leak indicator or watch the dial. If it moves while no water is in use, water is escaping somewhere on the property.
Test the toilets
Add a few drops of food coloring to each tank and wait without flushing. If color appears in the bowl, the flapper or fill valve is leaking.
Check appliances and irrigation
Look at the ice maker line, dishwasher, washer hoses, water softener and sprinkler timer, and check under sinks for damp spots. Also check the water heater area for moisture.
Look for clues on walls and floors
Check for damp drywall, staining, bubbling paint, musty smells, or a warm spot on a tile or concrete floor. These can point to where a hidden leak is.
When to call a pro
Call a plumber if the meter moves with everything off, the sound stops only when the main is closed and no toilet or fixture explains it, or you see stains, damp spots, warm floors or unexplained increases in your water use. Pinpointing a leak in a wall or under a slab takes leak-detection tools, and guessing can mean opening the wrong section of drywall or flooring.
Plumbing is a licensed trade in Florida under Chapter 489, Florida Statutes. We manage plumbing projects under our Florida Certified Building Contractor license CBC1265305, and our Florida-licensed plumbing subcontractors do the plumbing work, as s. 489.113(3), Florida Statutes provides. That covers Miami-Dade, Broward and Palm Beach counties only. Fixing a simple leak usually doesn't need a permit, but a water heater replacement or a re-pipe typically does. The licensed plumber pulls it, inspections follow, and the permit is closed out. Your local building department can confirm what applies to your job. An open or unpermitted job may come up at sale, refinance or insurance renewal. To start, call (954) 620-7812 or use the quote form.
Verify our building certification, or any Florida plumbing contractor's license, at Florida DBPR.
What a pro will do
- Locate the leakOur plumbing subcontractors use pressure testing and leak-detection methods to find the source, including slab leaks, before opening anything.
- Repair or replace the failed partThat may be a toilet flapper or fill valve, a faucet or fixture, a section of supply line, or a corroded fitting.
- Evaluate aging pipesIf the leak is from polybutylene, galvanized or deteriorating cast-iron lines, they will explain whether repair or re-piping makes more sense.
- Handle permits and inspectionsWhen the work is permitted, such as a water heater or re-pipe, the licensed plumber pulls the permit and we schedule the inspections through close-out.
- Put it in writingWe give a free estimate and a written scope before work starts, including any wall or floor repair after the leak is fixed.
Related questions
- Can a toilet really make that much noise on its own?
- Yes. A flapper that doesn't seal can let water seep into the bowl, so the fill valve keeps running or restarts at intervals. It's often fixed with a replacement part, and the food coloring test confirms it.
- Could the sound be my water heater?
- It can be. A tank heater refills after hot water is used, and a leaking tank or relief valve can also cause trickling sounds. If you see moisture around the heater or the sound continues for long periods, have it checked.
- Does a hidden leak cause damage even if I can't see it?
- It can. Constant moisture in a wall, ceiling or under flooring may lead to stains, mold or rot over time, and it often shows up first as a higher water bill. Finding it early usually keeps the repair smaller.
- Do I need a permit to fix a leak?
- Usually not for a simple leak repair or a like-for-like faucet or toilet swap, but rules vary. Water heater replacements and re-piping typically do need one, so confirm with your local building department.
Keep reading
Request a free plumbing estimate
Tell us what's going on. We'll get back to you; the plumbing work is done by our Florida-licensed plumbing subcontractors.
Prefer to talk?
(954) 620-7812