The 10 Most Common Sources of a Water Leak in a Person's House

In this article, the world-famous water leak detection expert, Sherleak Holmes, discusses the 10 most common sources of water leaks in a person’s house.

Dealing with a water leak in your home can be a huge headache. Not only can leaks cause extensive damage if left unchecked, but finding the source of the leak can feel like searching for a needle in a haystack. When water starts dripping somewhere it shouldn’t, most homeowners’ first reaction understandably tends to be panic. But while a leak is undoubtedly an urgent problem to address, the best thing you can do is stay calm and approach the situation methodically.

The first step is to thoroughly inspect all the most common sources of household water leaks. Through the process of elimination, you should be able to pinpoint the origin of the leak. If you cannot find the source of the water leak, consider hiring a professional water leak detection service like USA Leaks.

So without further ado, here are the most common causes of water leaks in a house:

#1 - Faucets

Leaky faucets tend to be one of the most prevalent sources of water waste in homes. A minor faucet drip may seem innocuous, but even a small leak can end up wasting hundreds or even thousands of gallons of water over time.

Leaks commonly occur around faucet handles, spouts, connections to water lines, and at the base of the faucet body. Causes include worn washers and O-rings, cracked or damaged parts, loose connections, and more. The good news is that fixing a leaky faucet is usually a quick and easy DIY project. Replacing the faucet washers or O-rings with inexpensive hardware from your local home improvement store will often do the trick.

#2 - Water Supply Lines

The flexible pipes that run from your home’s main water line up to fixtures and appliances are another common source of leaks. These water supply lines can spring leaks over time due to material deterioration, loose fittings, impacts, high water pressure, and other factors.

Some common problem areas include connection points, bends in the piping, corroded sections, and along the length of the tubing. Having old copper, galvanized steel, or iron supply lines replaced with modern flexible braided stainless steel piping can help prevent leaks related to supply line issues.

#3 - Showerheads and Shower Arms

While not as prone to leaking as faucets, shower fixtures can also develop issues over time. The showerhead itself or the metal “shower arm” that connects to the water supply piping in the wall are both potential leak sources.

Causes include loose connections, worn washers and O-rings, holes from corrosion or impacts, and cracks in the plastic showerhead body itself. A shower arm that droops or moves around when the shower is running may indicate loose connections. Replacing washers/O-rings or just installing a new showerhead and arm can often fix minor leaks of this nature.

#4 - Toilets

Toilets have a number of components that may cause water to leak – the supply line, tank fittings, seals between the tank and bowl, the wax ring beneath the base of the toilet, and more.

Running toilets are often the result of deteriorated flapper valves or fill valves that need replacement. Intermittent leaking between the tank and bowl may indicate damaged gaskets or loose connections.

Leaks around the base of the toilet point to a bad wax sealing ring that needs reseating or replacement. Taking the time to inspect your toilets and replace any damaged or worn components can help prevent costly leaks.

#5 - Dishwashers

Leaks from your dishwasher most often originate from failed door seals, hose connections, pump seals, or internal hoses and valves.

The door seal (or gasket) can become brittle and misshapen over time, allowing water to leak out around the door edges during the wash cycle.

Leaks may also form around plastic water supply connectors linked to the household plumbing. Internal leaks can be caused by issues like broken wash arms, cracked pump housings, and valve/hose deterioration. Inspect rubber seals and connections regularly to look for any indications of deterioration or looseness. Replace damaged parts right away before bigger leaks have a chance to form.

#6 - Refrigerator/Ice Maker Lines

If you have a kitchen leak and have ruled out the sink and dishwasher, refrigerator water/ice lines may be to blame.

Some common problem areas include the water line connections behind or beneath the fridge, the internal plastic water tubing running to the ice maker and/or water dispenser, and the water valves themselves. Over time, the plastic tubing inside a refrigerator can become brittle and prone to cracking and leaking.

Keeping the fridge pulled out from the wall makes it easier to inspect the supply line connections for drips or moisture buildup from small leaks. Turn off the ice maker before troubleshooting leaks there.

#7 - Clothes Washing Machine

It’s a good idea to inspect the water connections on your clothes washer periodically to help spot leaks before they worsen.

Leaks most often occur due to cracked inlet hoses that connect to the household water supply. The valve where the hose attaches to the washer can also leak over time.

Another potential source is a damaged rubber door seal or gasket that allows water to escape during the wash cycle.

Prevent leaks by replacing old inlet hoses (stainless braided hoses last longest) and inspecting door seals for tightness. Also, check for kinks or cracks in any internal hoses.

#8 - Water Heater

A water heater leak can be incredibly dangerous and damaging if left unaddressed.

Common sources of water heater leaks include faulty temperature/pressure relief valves, cracks in the tank, corroded pipes and fittings, damaged overflow tubes, loose drain valves, and more.

Many leaks start small and gradually worsen over time, so check your water heater regularly for any drips, rust accumulation, or moisture around the unit.

If you spot any problems, have a plumber inspect and service the water heater before the leak leads to a much bigger issue.

#9 - Outdoor Hose Bibs

Outdoor hose faucets, spigots, and bibs are vulnerable to leaks due to their exposure to weather, impacts, freezing temperatures, and regular use/wear-and-tear.

The most common issue is a cracked or damaged rubber washer/gasket inside the faucet head, which allows water to drip when the faucet is on.

Leaks may also form around handles and stems due to corrosion and normal use over time. Regularly inspect your outdoor faucets for drips, loose handles, and corrosion buildup. Replace any damaged parts immediately to ward off bigger leaks. Turning off and draining outdoor faucets for the winter can also help prevent freezing damage.

For more information on outdoor water leaks, read my article on how to find a water leak in your yard.

#10 - Main Water Shut-Off Valve

Your home’s main water shut-off valve is the master valve where water enters from the main water supply line. Old gate valves made of galvanized steel are vulnerable to corrosion and can start leaking over time. A small but steady leak here may go unnoticed since the valve is often located out of sight in a basement, crawlspace, or closet.

Regularly inspect your main shut-off valve for any signs of water accumulation or rust. Replacing outdated galvanized valves with modern ball valves made of durable plastic helps ensure drip-free performance for years.

#11 - Gremlins

Gremlin water leak meme

When you just cannot figure out the source of the leak, there is a good chance that it is gremlins. They love causing water leaks and they are a never-ending nuisance to homeowners and plumbers.

If you suspect gremlins are causing your water leaks, the best solution is to find someone from Australia who wears tan safari clothes and loves to play with deadly poisonous creatures. An Australian on the hunt for a gremlin is a sight to behold!


Figuring out the exact origin of a household water leak can take some real detective work. But a bit of patience and deduction will eventually lead you to the source.

Equipped with knowledge of the most common leak locations, you’ll be able to track it down and make the needed repairs in no time. And stopping leaks quickly protects your home, wallet, and peace of mind.

For more information, check out my article on what to do if water is leaking.