Leaking Pipe In Wall: How To Find, Repair Options & Cost

A leaking pipe in a wall happens when water, sewer, or gas lines hidden behind your drywall crack, loosen, or break, releasing moisture or fumes into your home. This can quickly lead to mold, musty odors, peeling paint, or even serious structural damage if ignored. In many cases, homeowners only notice the problem once their water bill spikes or the wall shows discoloration.

In this guide, we’ll walk you through how to spot the early warning signs of a leaking pipe, simple and advanced methods to confirm the source, and the different repair options available.

You’ll also learn what causes pipes inside walls to fail, how much common repairs cost, and when it’s best to call a professional plumber to prevent costly long-term damage. By the end, you’ll have a clear understanding of how to protect your home and budget from hidden pipe leaks.

How to find a leaking water pipe in your wall

A leaking water pipe inside a wall can usually be found by looking for visible damage like stains, peeling paint, or mold, and confirmed with tools such as a moisture meter or infrared camera. If the leak is severe, you may also hear dripping sounds or notice a sudden rise in your water bill.

Use these methods to track down where a water leak may be coming from:

Mold or mildew on walls – Mold looks like a cluster of black or brown dots on your wall. Sometimes mold grows on the inside, hiding from you until it bleeds through. Water saturation on your walls is the perfect condition for mold growth.
Sponginess – Touch your walls and feel if your drywall is soft or moldable. That be a sign water is leaking into your wall.
Dripping sounds – Of course, if a pipe is leaking, you may be able to hear faint drops of water dripping inside your walls.
Discoloration – Look for areas that look washed out or have a lighter color than usual.
Peeling paint or wallpaper – Check to see if your drywall is falling apart or is soaked with water.
Wet areas or puddles – If your appliances aren’t leaking, the water could be coming from behind your walls.
Musty smells – A water leak may smell “earthy” like an old basement.

*If you notice a strange spike in your water bill but can’t seem to find any of the signs above, it may be a little more challenging to find the leak. Here are more secure ways of detecting the location and source of a leak.

Check your water meter – Your home has a water meter that tracks the flow rate (how many gallons per minute are flowing through the meter) and how many gallons your family uses. Record the numbers you see, waiting at least 3 hours without using any water. Compare the numbers at the end, and if it has moved, you have a leak in your plumbing.

Use a moisture meter – Plumbers usually carry one of these with them, but you can rent or buy one from a hardware store. Point the device at your walls until you find the spot that gives the highest reading. That’s the point closest to the leak.
An infrared camera – An infrared camera cannot “see” moisture or water in your walls, but it detects coldness. When a water pipe is leaking, the camera will pick up the drop in temperature. Hot water pipes pop up as a heat source.

Cutting into drywall – The last resort. If there are visibly damaged areas on a wall or ceiling, cutting could be used to take a look around and see if you can find it. Keep in mind that signs of water damage don’t always mean that the leak is coming from that exact area. It could be just where the water has poured down to. Call the professionals before you take this drastic step.

How to find a leaking sewer pipe in your wall

Leaking sewer pipes can be found using the same methods above, except your sewer lines aren’t connected to your water meter, so that won’t help you. There are a few critical differences between a leaking sewer pipe and a leaking water pipe.

Sewer odor:

If you can smell sewage in your walls or home, that’s a sign a sewer pipe is leaking, exposing your home to disgusting fumes. If you find the wall where the smell is almost unbearable, that might be where the line is leaking.

Mold growth from humidity:

Just like a leaking water pipe, mold growth is a clear sign of moisture behind your walls. In this case, with a leaking sewer pipe, the increased humidity from the leak causes mold to grow just at the right temperatures.

Infestation:

Rodents and insects love to crawl and creep inside your sewer pipes when there is an opening. If you see signs of rats or other pests, think before you call the exterminator. The problem might be a nest somewhere, but it could be they are coming from your sewer lines. If that’s the case, call sewer line professionals.

Vapor test:

A vapor test can be performed where a non-toxic vapor is pumped through your sewer system from the vent openings on your roof. If there is a crack in the sewer pipes behind the wall, the vapor will fill the empty space behind the drywall and will make its way out of electrical outlets or other openings. Since a sewer system should be air-tight, any visible vapor inside your home would indicate a crack.

Read also – Signs of a cracked sewer pipe

How to find a leaking gas pipe in your wall

Gas lines usually run to an appliance, furnace, or fireplace. A leaking gas pipe is very dangerous to your health and safety. Look for these distinct signs.

You should also know where your gas shut-off valves are and how to operate them in case of an emergency.

The valve could be located near your gas meter, before your first gas appliance, close to your furnace, or water heater.

Sulfur Odor:

Natural gas is mixed with a very strong-smelling sulfur compound, like rotten eggs. That is a vital sign that there is a leak nearby.

Sounds:

Propane gas is odorless and difficult to detect if it leaks. Listen for “hissing” sounds behind your walls. Call a professional if you cannot find the source. Gas leaks are severe and need to be handled as soon as possible.

Causes of leaking pipes in walls

Pipes may break for all sorts of reasons, including but not limited to:

Backups – If you are flushing more than just human waste or toilet paper, your pipes begin to clog up. They are possibly building up near a joint, ruining the seal and allowing water to leak.
Rust – When exposed to water and oxygen, cast iron pipes can rust or deteriorate over time without proper cleaning.
Corrosion – Copper pipes are supposed to be “corrosion-resistant,” but that does not mean they are “corrosion-proof.” Copper pipes are susceptible to formicary corrosion, appearing as a black patch where the metal has weakened. This leads to pinhole leaks, and those are difficult to detect at first but will be a significant problem later.
Freeze – Water and sewer lines can be exposed to extreme temperatures. Pipes could freeze and burst, leaving you with a huge mess to clean up.

How to repair a leaking pipe

You repair a leaking pipe either by doing a targeted fix on the bad section or by replacing the run of pipe if it’s old, corroded, or leaking in multiple spots. Start by shutting off water (or gas), relieve pressure, and contain the leak; then choose one of the options below.

There are two solutions when it comes to fixing a leaking pipe: minor repairs and total replacement.

Minor repairs – These can involve cutting into your drywall, finding the source of the leak, and then replacing the damaged sections. Or the plumber might put a simple patch over the leak and call it a day, but only if the leak is isolated.
Total replacement – Plumbers might decide that your entire system needs to be replaced, especially if your pipes are old or have the possibility for future leaks.

We break down the cost of potential repairs below. If leakage has been going on for a long time, and there is so much water damage, you may need to call restoration experts as well.

They can help extract water from your home, dry your walls, clean any affected personal items, and help with any insurance claims. They may be able to stop the leak, but plumbers are the ones who can help install new plumbing systems.

Cost to repair a leaking pipe in your wall

Based on what sort of pipes need repair, the prices are broken down below.

Water pipes – Leaking water pipes cost an average of $150 to $350 to repair. Finding the leak may cost an additional $100. This does not include repairing your drywall after it’s fixed. Drywall repair costs an additional $250 to $750, depending on the hole’s size and location. If a pipe froze and burst, you might be looking at paying $1,000 to $4,000 in water damage and cleanup. Total replacement for water pipes could run anywhere from $350 to $2,000, and that doesn’t include the plumber’s hourly fee.

Sewer pipes – If you have a leak in your sewer line, most plumbers won’t recommend small repairs. They tend to be rush jobs and don’t solve the real problem. In that case, plumbers suggest trenchless sewer repair or conventional sewer repair. Trenchless sewer repair, on average, runs $60 to $250 per linear foot. The price depends on various factors, such as the pipe condition, ease of navigation, the amount of cleaning needed before the lining, the amount of piping, and the accessibility of the pipe. Conventional sewer repair, on average, costs $50 to $450 per linear foot. The price to install brand new pipes throughout your home or yard could run to $15,000 because of all the extensive work, such as trenching and excavation.

Gas pipes – Gas line repair can cost $250 to $750. To run a new gas line, it’ll cost an average of $535. However, it can range anywhere from $120 to $1,350. Most homeowners spend between $259 and $815.

If you have issues with your water and sewer lines, call New Flow Plumbing today! We’ll get you started with a CCTV sewer camera inspection to determine where your problems come from. Then, we give you a free repair estimate, followed by available repair options. Whatever the issue, New Flow Plumbing will have your plumbing lines running again.

FAQs

How do I know if a pipe is leaking inside my wall?

You can often identify a hidden leak before seeing water by looking for subtle changes in your environment. Watch for clustered mold growth (black or brown dots), “spongy” or soft drywall texture, peeling paint, or washed-out discoloration on the wall. If you hear faint dripping sounds or smell a persistent musty, earthy odor similar to an old basement, you likely have moisture accumulating behind the drywall.

Can I fix a leaking pipe in a wall myself?

DIY repairs are possible for minor leaks but involve cutting into your drywall and potentially compromising your home’s structure if done incorrectly. You must shut off the water, cut the wall to expose the pipe, and either patch or replace the section. However, without professional diagnostic tools, you may miss the true source. New Flow Plumbing recommends a professional assessment first; we offer free repair estimates to help you decide if a quick patch or a permanent professional replacement is the safer investment.

Does homeowners insurance cover leaking pipes in walls?

Homeowners insurance generally covers water damage if the leak is “sudden and accidental,” such as a burst pipe from freezing. However, most policies usually do not cover the cost of repairing the pipe itself or damage resulting from “gradual” leaks that have been ignored over time (negligence). You should contact restoration experts who can help extract water and guide you through the insurance claim process to ensure you get the coverage you are entitled to.

How much does it cost to repair a leaking water pipe in a wall?

Repair costs depend heavily on the type of pipe and the severity of the damage. A standard water pipe repair typically costs between $150 and $350, plus an additional $250 to $750 for drywall restoration. For sewer lines, New Flow Plumbing specializes in cost-effective trenchless repairs that range from $60 to $250 per linear foot, saving you from expensive excavation. We provide clear, upfront pricing so you know the exact cost before any work begins.

What happens if you ignore a leaking pipe in the wall?

Ignoring a leak is a financial and structural hazard. Over time, consistent moisture rots wooden framing, compromises drywall integrity, and encourages toxic mold growth that can spread throughout the home. Beyond the structural risks, “gradual” damage is often rejected by insurance companies, meaning you could be personally liable for thousands of dollars in restoration costs if the problem is not addressed immediately.

Are leaking sewer pipes in walls dangerous?

Yes, leaking sewer pipes are a severe health risk because they release harmful bacteria and disgusting fumes into your living space. Symptoms include a distinct sewage smell, humidity-induced mold, and even rodent infestations. If you suspect a sewer breach, New Flow Plumbing can perform a non-invasive vapor test to confirm the leak’s location without tearing down your walls, ensuring your home is safe and sanitary.

Is a gas pipe leak in the wall an emergency?

A gas leak is an immediate emergency. Natural gas is scented with a sulfur compound that smells strongly of rotten eggs; if you smell this, or hear a hissing sound behind your walls, evacuate immediately. Propane is odorless and harder to detect without professional equipment. Do not attempt to find these leaks yourself. Shut off your gas valve if it is safe to do so and call a professional utility service or plumber instantly.

Can plumbers detect leaks behind walls?

Professional plumbers use advanced technology to “see” through your walls without cutting them open. At New Flow Plumbing, we utilize infrared cameras to detect temperature drops caused by leaking cold water and sensitive moisture meters to map the wet area. For sewer lines, we use CCTV camera inspections to visually locate cracks or blockages deep within the system, ensuring an accurate diagnosis without the mess.

What tool is used to find a water leak in a wall?

The most effective tools for homeowners are a moisture meter and a water meter. A moisture meter can be purchased at a hardware store; by pointing it at the wall, you can identify the spot with the highest reading, which is usually closest to the leak. An infrared camera is also excellent for detecting temperature differences (cold spots) on the wall that indicate wet insulation or drywall.

How to test for leak behind wall?

To confirm a leak without tools, perform a water meter test. Record the numbers on your home’s water meter, then ensure no water is used inside or outside the house for at least 3 hours. Check the meter again; if the numbers have moved, you have a leak. For sewer lines, a vapor test is best. Non-toxic smoke is pumped into the system, and if it escapes through outlets or walls, it reveals the exact location of the crack.

How do I know if my water is slowly leaking?

Slow leaks are dangerous because they are silent budget killers. The most reliable sign is an unexplained spike in your water bill despite normal usage. You may also notice low water pressure or areas of the floor that feel constantly damp. New Flow Plumbing can help you catch these elusive leaks early with a comprehensive system inspection, preventing minor drips from turning into major structural water damage.

Arman Grigoryan

Founder & President of New Flow Plumbing

Arman Grigoryan is the founder and president of New Flow Plumbing, proudly serving Los Angeles, Sacramento, and surrounding areas. With extensive experience in plumbing diagnostics, he leads a skilled team specializing in advanced sewer and drain camera inspections to quickly identify problems and deliver lasting solutions. Arman is dedicated to using the latest technology to provide reliable service, honest answers, and dependable results for every customer.