14 Signs You Have a Water Leak—And the Fastest Way to Detect It

Few things are more frustrating as a homeowner than dealing with water damage. You try to keep your home in good condition (and maintenance costs low), only for small water leaks to snowball into major catastrophes that burn a hole in your pocket and dampen your spirits. It’s disheartening, but you don’t have to feel helpless. There are smart home devices that can help catch leaks early to help limit or prevent water damage (more on this later). But what if you have one of these devices? How can you tell if there’s a water leak in your home?

What are Some Common Signs of a Household Water Leak?

No matter the age, location, or size of your home, there’s a good chance it will spring a leak at some point–whether from a drippy faucet, overflowing drain pipe, or faulty appliance. The worst part? Leaks can crop up anywhere and anytime and be disastrous over time if left unchecked.

If you’re concerned that your home has a water leak, watch for these signs:

1. Water Stains on Ceilings or Walls

One of the most obvious signs of a household leak is yellow or brownish water stains on the ceilings or walls that encase plumbing. As water makes contact with these areas, it can leave behind unsightly marks that are hard to miss.

Water stains often start small but spread out wider if the leak continues. Sometimes, you may also notice the drywall or plaster beginning to bubble up or become soft and soggy. Eventually, it will warp and break apart.

If you notice this kind of water damage, you may need to open up the ceiling or wall to check the condition of the plumbing behind it. A leak in the roof is usually easier to access through the attic and will help you avoid patching the drywall. If there is a leak in the wall plumbing, you should be able to access it via a panel on the opposite side.

2. Unusually High Water Bills

For most homeowners, water bills are (or should be) consistent. As long as the water usage remains steady, there shouldn’t be any sharp increases. Sometimes, you may see upticks after turning on your sprinklers to water your lawn or garden or refilling your swimming pool to keep the water fresh. But if your water bill has suddenly skyrocketed for no apparent reason, you may have one or more undetected leaks. These leaks usually spring underground, behind walls, or in other hidden areas in your home.

According to the EPA, the average household wastes more than 10,000 gallons of water a year, while 10 percent of homes have leaks that waste 90 gallons or more daily. Do the math on that, and you’ll quickly realize how many extra dollars can get added to your monthly water bill, all because of a seemingly harmless leak you weren’t aware of.

So, don’t just brush off an oddly high water bill. Start hunting around your home for leaks that may be driving up your expenses, and monitor your monthly water bill.

3. Foundation Cracks, Buckling, and Leaning Walls

When water continuously seeps into concrete foundations over a long period, it can cause the structure to crack, buckle, and shift out of place. This can lead to foundational issues like leaning basement walls, large cracks in the foundation floor, or displaced moldings and trim—all signs of chronic leaks and moisture buildup underground.

With this in mind, don’t ignore even small hairline cracks in your foundation, as they can quickly grow bigger. Also, try your best to control undetected leaks to help preserve your home’s structural integrity and safety.

4. Musty Odors

Have you noticed an earthy or musty smell in your home lately, even after regular cleanings? This is another sign of a potential leak causing water to build up inside your walls, crawlspaces, or elsewhere.

Even if you can’t see visible signs, that strange odor may indicate something is amiss. Excess moisture creates the perfect breeding ground for mold and mildew, giving off that distinct musty odor.

If you notice these smells seemingly out of nowhere, don’t just cover them up with air fresheners; keep looking for the leak until you locate the source.

5. Wet Spots or Moisture on Floors and Carpets

Major indoor water leaks typically flow to one place: the floor. Therefore, damp spots or moisture may appear on carpets and rugs, especially in corners or along baseboards and trim. You may also notice unusual smells, discoloration, or a feeling of dampness underfoot.

Wet carpets are a surefire sign that moisture is seeping in from somewhere. Worst case, the entire room may be flooded. The sooner you locate and fix the leak, the better, as water damage, mold, and mildew growth can quickly occur and contaminate the indoor air.

6. Flaking Paint or Wallpaper Bubbles

When water from a leak seeps behind walls, it can collect under the paint. Over time, the paint will start flaking, peeling, and chipping off the wall. Various minerals in the water can also create dark spots or other discoloration on the paint. Even worse, if the water sits on the wall too long, the wall material may rot, warp, swell, or crack, weakening the structure.

You may also notice your wallpaper peeling away or forming bubbles where water is trapped behind it. These are signs of dampness and potential leaks left unchecked. Investigate the affected areas further and check for hidden sources of moisture to prevent more significant problems down the road. Once you notice any water damage, turn off and unplug any nearby electronics to prevent potential electrical fires.

7. Mold Growth

Mold typically thrives in moist, dark areas—and pipes hidden in a wall or under flooring provide the ideal conditions. So, if you spot any signs of mold growth (fuzzy splotches, green or black streaks or blemishes, etc.) or have an allergic reaction, like irritating eyes or wheezing, you may have a water leak. Investigate further and clean the mold thoroughly so it doesn’t spread.

Bear in mind, however, that it’s normal for a bit of mold to develop wherever water accumulates, such as around faucets or in the corner of a shower. However, if you notice it in non-shower areas of your home, it’s a clear sign that water is leaking somewhere and seeping into those areas.

Mold can develop within as little as 24-48 hours after a leak. If left unchecked, it can spread rapidly through walls, attics, crawlspaces, and ductwork, creating an unhealthy indoor environment and causing structural damage.

8. Blistering or Peeling Exterior Paint

While interior paint and wallpaper defects often signal indoor moisture problems, the same can occur outside your home. Walk around the exterior and look for places where the paint is bubbling, cracking, or peeling off in sheets. This cosmetic damage often indicates leaks behind the walls, allowing water to seep and degrade the paint. If you notice such signs on your exterior paint, wait until you’ve investigated and fixed the underlying leak before repainting walls with these problem areas.

9. Termite Activity or Wood Rot

Termites and other wood-destroying insects are naturally attracted to damp, rotting wood—like bears are to honey. The moisture makes the wood softer and easier for them to burrow into and eat away at. So, if you start noticing termite tunnels, piles of sawdust, or shed insect wings around your home, it’s a good indicator that moisture is getting to some wood components and causing rotting and harboring insects.

Wood rot itself is also a major red flag when it comes to leaks. As wood stays overly damp for a prolonged period, it begins to soften, warp, crack, and essentially break down from the inside out. This may manifest as buckling wood floors, swollen baseboards or walls, or even structural supports starting to get spongy. The moisture could be from precipitation leaking in, but it’s more likely a leak from interior plumbing or appliances that keep these areas chronically damp.

10. Dripping Sounds Within or Behind Walls

Interior plumbing pipes and drain lines can run behind the drywall or surface walls. Usually, these pipes should be completely dry outside when no fixtures or appliances are running. However, if you hear noises like dripping, rushing, or flowing water coming from within or behind wall cavities, there could be a leak in the pipes or drains inside those spaces.

The water escaping from a crack, loose joint, or hole in the pipe gets caught between the pipe and wall cavity. You’ll hear those liquid movement sounds reverberating through the hollow spaces as the water drips and trickles down. These noises may be constant, or you might only notice them at certain times when the pressure in the pipes changes and forces more water through a compromised section.

The bigger and more extensive the leak, the louder and more apparent the dripping, rushing, or slushing sounds will become as more water escapes. However, even small pinhole leaks sometimes release enough water to create slight dripping sounds behind the walls.

11. Bathtub Stains or Standing Water

Here’s a common one in many households—stains, cracks, or chips around the base of toilets, bathtubs, and shower areas where silicone caulk seals can start deteriorating and letting moisture in behind walls. These visible signs may be due to excess moisture from a leak. Also, watch for pools or puddles of standing water forming on bathroom floors after showers. These are often signs that tub and shower leaks are seeping into floors below.

12. A Constantly Running Water Meter

Your home’s water meter is designed only to run and measure water usage when a fixture or appliance actively uses water inside the house. When everything is turned off, and no water is being used, the meter reading should remain constant.

However, if you check your meter and notice that the reading is continuously increasing even when every water outlet is turned completely off, it’s a tip-off that a leak somewhere is allowing water to flow out undetected. The meter keeps running and measuring that added water volume because it is continually drawn through the system and down the drain by the leak. Since it’s not being used for any intended purpose, it’s just wasted water constantly flowing out.

Check your meter reading before and after a 2-3 hour window when no water is being used. If the reading changes, you likely have an underground leak in your service line or pipes under the slab that need investigating.

13. Warm or Hot Spots on Floors

In some homes, the heating system runs by circulating hot water through pipes installed underneath the flooring. This is called radiant floor heating. When working correctly, these pipes provide an even, consistent warmth across the entire floor surface. However, if one of those hot water pipes develops a leak, it can cause a very localized hot spot to form on the floor in that specific area.

The leaking hot water raises the temperature significantly compared to the surrounding floor. You may notice one patchy section of the floor that feels noticeably warmer or even hot to the touch when the rest feels just moderately warm. In some cases, it may even make the flooring material soft and buckle up from the excess heat and moisture in that spot.

These “hot spots” indicate that a pipe carrying the hot heating water has sprung a leak directly under that portion of the floor. Rather than the heated water continuing its full circulation, it’s seeping out and transferring its heat directly into that isolated floor zone.

14. A Wobbly Toilet

You expect to feel stable and comfortable when you sit on the toilet. However, you know something is wrong when it feels wobbly, like it’s about to break.

Toilets are often very heavy and designed to sit firmly in place on the bathroom floor. If yours feels loose, it may be a slow leak from the toilet (perhaps a crack in the porcelain base or a worn wax seal underneath). Or it could be from another nearby leak, like a bathtub, shower, or sink, allowing water to soak through to the toilet area.

Whatever the case, use that looseness or rocking motion as an early warning to inspect further for an active leak. Identifying the source of the leak and repairing it will help you get that toilet securely re-set and reinforced and prevent any major floor or sub floor damage.

15. Reduced Water Pressure

The pipes that bring fresh water into your home are a network of connected tunnels or pathways. When no leaks or obstructions exist in the network, water flows smoothly through these pipes at standard pressure. However, a crack or hole letting water out anywhere along those pathways creates an escape route for the water.

Some water trickles or spews through that leak rather than continuing through the pipes. With less water going to fixtures like sinks, showers, and appliances, you may notice reduced pressure from those taps and outlets. That’s because the water doesn’t have as much force behind it flowing through.

You might experience this as a small trickle when you expect a stronger flow. Or the pressure gradually drops off while the water is running. Some areas may have decent pressure, while others have very low flow.

How to Detect and Stop Household Water Leaks Before They Cause Damage

Anyone who’s ever experienced water damage in your home knows how inconvenient, costly, and destructive it can be–especially when precious valuables and family heirlooms are lost. And as such, they likely never want to relive those moments.

If you’re ever going to prevent a recurrence or first-time experience, you’ll need to catch future leaks before they spiral into full-blown floods or show obvious signs of damage. While routinely checking leak-prone areas is a good start, some leaks can still go undetected and wreak havoc when you’re away or unaware. How do you safeguard against these hidden leaks?

Smart Water Leak Detectors: The Basic Solution

Flo Smart Water Leak Detection & Shutoff Valve
Flo by Moen – Water Leak Detection & Shutoff

Smart water leak detectors are the easiest, quickest, and least expensive way to protect your home from water damage. These tiny sensors come in different shapes and sizes, but all work the same: you place them near leak-prone areas in your home, like around water heaters or washing machines, and if a leak occurs and water touches the sensor, it sends a notification to your phone and/or sound an alarm.

Keep in mind, however, that water leak detectors are limited in that they only detect leaks if the water touches the sensor. If the water flows in a different direction, the sensor may completely miss it. They also can’t detect small drips from faucets or running toilets unless there’s enough spilled water to trigger the sensor. Even when working perfectly, these water sensors can only alert you to the leak; they can’t shut off the water flow themselves.

So, while leak detectors are a convenient way to stay abreast of larger spills and leaks, they don’t completely protect against water damage. You still need to find and fix the root cause when alerted. Nonetheless, using them is way better than being caught off-guard by major water damage from a leak that’s likely been running for weeks.

Learn more: Top 7 Benefits of Smart Water Leak Detectors for Your Home

Smart Water Monitor with Automatic Shutoff: The Whole Shebang

While more expensive than water leak detectors, smart water monitors with a shutoff valve provide the highest protection against home water leaks. The Flo Smart Water Monitor & Shutoff is a perfect example, offering exceptional whole-home protection against water damage from hidden leaks.

This device monitors the pressure and flow rate of the water passing through your pipes to learn your home’s water usage patterns. That way, it can quickly identify abnormalities like running water or leaks even as small as a drop per minute–anywhere in your home. Once it “senses” an unusual pattern that could indicate a leak, it notifies you in real-time via the Smart Water App, phone call, and email so you can turn off the water. Otherwise, you can set it to automatically shut off the water to reduce waste and prevent extensive and expensive water damage.

These upgraded smart devices cost around $500 and usually require a plumber to install them, adding a bit to the initial cost. Besides, some home insurance companies offer huge discounts or rebates for installing one in your home. This can help make up for the higher initial cost over time.

So, while on the pricier end, smart water monitors with automatic shutoffs offer maximum protection by monitoring your home for leaks and physically restricting water flow before flooding occurs. Talk about peace of mind.

Final Thoughts

As a homeowner, water leaks can be your worst nightmare. If left unchecked, they can lead to expensive water damage and destroy your peace of mind. The key is to watch for any signs indicating a hidden leak. Catching the leak early prevents it from escalating into full-blown catastrophes that may require significant repairs.

With a whole-home water monitor and shutoff, you get an extra set of eyes continuously monitoring your home for abnormal water usage that could signal a leak, no matter how small. The ability to automatically shut off the water supply at the first sign of a problem is an incredibly valuable safeguard against devastating water damage.

To learn more about smart leak detectors and monitors with automatic shutoff, please call us today at 800-589-5592.