Certainly, some of the sounds you hear in your house are totally normal (your fridge intermittently running, the occasional creak of the house settling) but there are others that are cause for concern — indicators of what might need to be fixed, replaced, or even exterminated.We asked professionals which thuds, clanks, or hisses could mean that something is amiss. Once you've identified the source of a troubling sound (or even if you can't), we absolutely recommend you call in a pro to fix the issue.1. You hear water running — but nobody is using it."First, check the house quickly to see if any toilets are running, or flappers are sticking," says Alfonso Jimenez, master plumber and president of Mr. Rooter Northern Colorado. "Next, check if your sprinkler system, dishwasher, or washing machine is running. If you're still stumped, I would turn off the house's water and check for visible water damage throughout the home, and look for water pooling in the yard, around the outside of the house, or in the crawl space."

2. Your AC is banging or squealing."If the air filter isn't replaced regularly, it will ultimately get totally plugged with dirt and dust," says Dan Deardan, owner of Just Right Heating and Cooling. "This could cause the air handler to make a high pitched whining sound, and the same is true of your furnace filter.""Air conditioners can vibrate a lot, so parts can come loose over time, and cause banging or clanging." says Scott McGillivray, contractor and host of HGTV's Income Property. "Squealing could mean your fan belt is loose, and gurgling could mean you need to refill the refrigerant. Have your unit serviced by a professional."RELATED: 3 Things You're Forgetting to Do With Your AC »3. Your furnace is making a racket."A booming sound coming out of a gas furnace or boiler happens when the burners are not lighting properly, says Deardan. "Gas builds up in combustion chamber, and the delayed ignition causes a small exploding popping sound. This will only get worse, and cause larger, dangerous explosions over time, so call in a pro to handle the problem."

4. You suspect you've got critters."The most common noise inquiries we get from homeowners are concerns about sounds coming from the attic. Fast moving scurrying noises are often rodents like squirrels or rats, " says Bob Cherrington, owner of Family Pest Control."cleaning air ducts in apartmentRodents are dangerous to ignore since they will chew just about anything, like electrical wires." will air purifier help with allergies"Many house fires are caused by rodents who short out the electrical wires."air purifier singapore deals5. You hear scratching in your gutters."Sometimes people mistake scratching in their walls for birds outside in their gutters," says McGillivray. "If you hear scratching regularly, it's likely a rodent in your walls.

A tinny scratching sound could be a bird's feet in your gutters, but this points to a different problem. Birds hang out in gutters when water pools. And if water is pooling in your gutters, it means the slope is incorrect. Have your gutters and downspout inspected to make sure water is being properly routed away from your house. "6. Your lights are buzzing."If you hear a buzzing coming from outlets or light fixtures, that's usually a sign of a loose connection," says McGillivray. "Loose connections can cause sparking, which can lead to electrical fires."7. Your fridge is popping — or won't stop running."When it comes to fridges, popping and rattling could point to compressor issues," says McGillivray. "A constant humming (meaning the fridge is constantly cooling and never 'cutting out') could indicate a temperature regulation issue. Make sure nothing is blocking the passageway between the freezer and the refrigerator compartments (this can happen when you pack too much food in the freezer)."

You should also clean your refrigerator's coils at least once per season (monthly is even better) to keep it running efficiently. Your vacuum's crevice attachment can help make quick work of the job.RELATED: The Essential Guide to Cleaning Your Fridge »8. Your dryer is screeching."Dryers tend to reveal problems with noise," says McGillivray. "Squealing could mean belt issues — I've seen dryer drums come right off because of loose belts. People often forget to remove the shipping bolts on new washers and dryers. If it's the first time you're using the machine and you hear a loud banging, it's often because the shipping bolts haven't been removed."9. You suspect a hissing sound that you worry could be a gas leak."This would indicate a dangerous situation," says Dearden. "If you can hear the hissing sound of a gas leak (you might also smell it), leave the house as fast as possible without touching any light switches or using anything electric, like a telephone. Get as far away from the home as possible, but don't start your car.

Call 911, and warn your neighbors get far away, too."More Household Smarts:• 9 Steps to a Brilliant Bathroom Makeover • 11 Big Mistakes You Make Painting Cabinets • The Major Reason You Need to Clean Out Your DryerUse the Click/Pop Eliminator and DeClicker effects Watch this tutorial to learn how to remove clicks, pops, and common noises from your audio tracks in Adobe Audition CC. (Watch, 10 min)My grill won't light. What could be the reason? If you can light the grill with a match you may have an ignition switch problem. Check your igniter switch. Is it making a clicking noise? If the igniter does not click, it is not aligned correctly with the gray rocker switch. To align it, remove the control panel (consult your owner's manual for instructions). Once the control panel is removed, check the position of the igniter. It should be tightly secured with the lock nut in the smaller hole of the keyhole frame. If the igniter has clips on the sides, rather than a lock nut, make sure it is completely “snapped" into place.

If the igniter is aligned properly, make sure the control panel is not loose. There should be two fasteners holding the panel in place. Next, check to see if the igniter wires are loose. The white and black wires should be secured at both ends. Then check the position of the metal tab protruding from the cookbox where the white wire attaches. This tab must be 45 degrees away from the cookbox to avoid a shorted circuit. Finally, very humid or rainy weather can cause moisture to collect on the end of the probe and make the igniter unable to spark. To remedy this condition, light the grill with a match. The heat from the grill will warm the probe and should fix the problem. Electronic igniters must be pushed and held until it clicks. If pushing the igniter button does not light main burners, and you cannot hear the igniter sparking: Check that there is a battery in the battery holder. Check that the battery has been installed in the battery holder properly. The positive end of the battery goes into the holder "up".

Is the cap of the battery holder (with the red button) screwed on tightly? Are the white wires connected from the battery holder to the ignition module? Each valve has its own igniter. When the control knob is turned from off to high, a spark is created. This may need to be repeated 3 or more times to ensure ignition. If igniter has a spark, but burner tube will not light try removing the grates and flavor bars to see if the igniter is sparking. If a spark can be seen, but the burner tube still will not ignite, the electrodes may be dirty. Gently clean the electrodes with a tissue. If igniter does not spark check to be sure all the wires are hooked up properly. If you cannot light the grill with a match you may have a gas flow problem. Have you cleaned your burner tubes recently? It is very important that the portholes of the burner tubes are clear of any blockage. If the gas flow is restricted, the igniter will struggle to light. To clean your tubes, brush the portholes with a steel wire brush in an up and down motion.