Once your floor is flooded, your ceilings are warped and your house is infested with mold, water damage can be expensive to fix.

But there are steps you can take to identify leaks, long before you notice a puddle on your floor or a water mark on your wall. Below, home experts share the sneaky warning signs of a leak to watch out for that you might not expect.

1. Low Water Pressure

If your shower or kitchen faucet suddenly starts drizzling less water than usual, pay attention. It’s not normal for it to take forever to wash a dish.

A sudden drop in pressure can be one of the most common warning signs you are experiencing a leak, said Katie Whitaker, licensed home inspector and owner of Handyma’am Home Inspections.

“If you’re on municipal water from a city...and you experience a drop in pressure, you almost definitely have a leak,” they said. (How can you tell if you use city water? If you receive a regular water bill and don’t have a well on your property, you likely use water supplied by your local municipality.)

Plumbing relies on pressure to get water to your home appliances. “When you experience the drop in pressure, that means that closed system [of your plumbing] has been compromised,” Whitaker explained. “So the water is going somewhere it’s not supposed to go.”

2. Weird Basements Smells

If your basement starts smelling funkier than usual, this could be a worrisome sign of a potential leak.

“If you have a leak that you can’t visibly see, especially in a basement, you’re going to notice a change in the smell,” Whitaker explained, noting that these smells might stink like wet laundry or mildew.

Whitaker gave the example of a leak in their own basement, which is made up of cinder block and is lined with plywood. “So if I have water coming in, I can’t see it, but because I have wood, because the wood is painted ― that’s what’s causing the funky smell,” they explained. “Because water is trapped back there and it’s causing organic growth.“

In Whitaker’s case, “I knew I had a problem because I had a dehumidifier running, so I had already eliminated that as a potential thing,” they said.

3. High Water Bills

If you experience sticker shock from one month to the next on your water bill, there could be a potential leak that is causing this price spike.

“You always want to check with the water department if rates have gone up, and compare it to your last bill,” said plumber Kelly Ireland. “But generally, if your water bill does go up, it’s an issue with your toilet or you have a sink dripping.”

The most common leak Ireland encounters is a toilet leak, which might not necessarily damage your home, but will cause you to pay more than you should. Ireland said early signs of this type of leak are when you keep hearing running water 20 minutes after no one uses the toilet or intermittently throughout the day.

This continuous noise is likely because the toilet flapper has gone bad or flush valve parts need to be replaced or repaired, Ireland explained.

4. Lawns That Sink

Major leaks from your water or sewer line can show up in your front yard. It can look like your lawn has “a big dip in it,” Ireland said as one example, or like “water coming up onto the sidewalk.”

Any “irregularities in your sidewalk or your lawn over time, if it’s progressively getting worse, could be due to a leak,” Ireland said.

5. Poor Caulking In Bathrooms

Ireland said when clients call about leaks appearing on ceilings, the most common culprit is a poor caulk job in the shower or tub. Early signs of this might look like grout cracking or loose tub spouts.

“Maybe you don’t even see that you have a leak in your wall, but when you turn your shower on, the whole handle shakes,” Ireland said as one example. A loose tub spout “generally will cause water to get into the wall,” she said.

What You Can Do To Test If You Have A Leak Before Calling Professionals

Before you call a handyperson to inspect what might be going wrong, you can do your own home inspection to test for leaks.

Get a moisture meter.

Whitaker recommends investing in a moisture meter to test if there actually is water trapped in your walls.

“Having a moisture meter on hand really gives you the power to be in charge of what’s going on in your home,” they said. “It will tell you if there’s moisture in your wall, and it’ll tell you what percentage.”

Do a paper test.

If you are unsure whether your faucet is leaking or not, do a quick test, Ireland suggested.

Put a paper towel or piece of cardboard under your sink and walk away for five minutes. If there is a leak, you “should be able to see where it is on the paper towel,” she said.

Check your water meter.

Water meters, which are typically found on the outside of your home near a curb, can give you clues as to whether you are experiencing a leak. This can be particularly helpful for leaks that are less obvious because insulation is absorbing the water.

Ireland explained a water meter often will have “a little dial on it that will spin.” And if that dial is moving, “It means that you have a leak somewhere,” she said.

And then call a professional.

If you run all your tests and you are still confused about what could be happening, it might be time to call a plumber or your local handyperson.

They can inspect the type of pipes that you have, how big your well pump is, or what water appliances you use to help determine the source of the leak.

You don’t want to hope it will go away, because it likely will not resolve on its own.

“You don’t want to risk any structural damage if it’s leaking into the foundation or into supporting walls,” Ireland said. “Mold and and structural damage would be the main issues of ignoring it or letting it go.”