Can a drain line leak under a slab?

Yes. A crack, a failed joint or a shifted section can let waste water out into the soil. Because it is not pressurized, it can be smaller and intermittent than a supply leak.

Does a drain leak make my water meter move?

No. The water was already used by the time it enters the drain, so the supply meter does not show it. A still meter with a damp floor leans toward a drain line, though other causes exist.

Do you clear blocked drains?

No. The technicians we connect you with find and fix leaks, including leaking drain lines under the slab. A slow or blocked drain is a plumber's job.

How do you test a drain line?

The technician isolates a section and tests it, for example by filling it and watching for a drop. A small camera may also be used to inspect the inside of the line.

Will I have to open the floor?

A repair under the slab usually means opening the floor above the damaged section. The technician explains the plan once the leak is located.

Can roots cause a drain leak?

In some areas, yes. Roots can enter at joints and cracks. This is more common near large trees, such as the oaks of North Florida. The technician describes what they find.

Is it safe to stay in the house?

The technician can tell you what is practical. Keep children and pets away from damp areas near a suspected drain leak, and avoid using fixtures on the affected line if it is getting worse.

What should I tell the dispatcher about drain line leaks under the slab?

Where the damp or smell is, when it appears, whether the supply meter moves, past drain problems and roughly when the home was built.

Under-Slab Drain Line Leak Services in Florida

The problem: a leak without pressure

A supply line leaks because it is under pressure and water is pushed out through a hole. A drain line works differently. It runs by gravity, carrying water away from fixtures, and it leaks when a crack, a failed joint or a shifted section lets some of that water out along the way.

Under the slab, that water goes into the soil. Because a drain line is not pressurized, the leak can be smaller and intermittent: it happens when water is running through that part of the line. The signs are different from those of a supply leak, and the meter does not move, since the water was already used.

Drain cleaning is not offered. If your problem is a slow or blocked drain, that is a plumber's job. This page is about a drain that leaks.

What owners notice

Signs may include a persistent damp smell or mustiness in a room, a damp patch near a bathroom or laundry that returns after drying, soil that sinks or is soft near the slab edge, or recurring drain trouble that a plumber cannot explain. Some owners see staining at a baseboard near a bathroom.

Because the meter does not move, the water bill is not a guide. If there is no change in the meter and no warm spot, but damp keeps returning near a drain, a drain line is one of the possibilities. A technician can test it, and ruling it out is useful as well.

A person answers, day or night.

Call Now: (855) 731-0997

Why older Florida slabs can have drain leaks

Many Florida homes from the middle decades of the last century have drain lines that run under the slab, often in materials of that period. Over many years, joints can open, sections can crack and the ground below can shift slightly. We cannot say which material your home has, since renovations and repairs vary.

Roots from large trees can find their way into lines in some areas, particularly in North Florida, where oaks are common. In sandy soil, escaped waste water drains away without much surface sign, so a leak may go unnoticed for a long time. See why Florida leaks hide.

What to do and what not to do

Note where the damp or smell is, and when it appears: after a shower, a wash load or a toilet flush, or all the time. That pattern helps the technician. Avoid using the fixtures served by the suspect line if the problem is obvious and getting worse, and call.

Please do not pour chemicals, enzymes or products down the drain to cure a leak, and do not dig around the slab edge. Waste water can carry contaminants, so keep children and pets away from a damp area and wash your hands after touching affected items. If you smell gas, leave and call the gas utility and emergency services from outside.

NoteWhat to write down

Where the damp or smell is. Room, wall and distance from a bathroom or laundry.
When it appears. After which fixture, or whether it is constant.
Whether the supply meter moves. A still meter with a damp floor leans toward a drain line.
Past drain trouble. Repeated slow drains or repairs, and where.

Options and price before work begins.

Call for Upfront Pricing

How a drain leak is found

The technician starts by isolating the drain system and considering which fixtures feed which sections. The line is then tested, for example by filling a section and watching for a drop, and the route of the pipe is checked. Where an internal view of the line is appropriate, a small camera can show cracks, offsets and joints.

Acoustic methods are less useful for drain lines, since there is no pressure, so testing and inspection do most of the work. The technician explains what was found and where. See how slab leaks are found.

Repair options

A section of a drain line under the slab is often repaired by a spot repair, in which the floor is opened and the damaged section replaced. A drain line can also be rerouted, though it depends on the fall needed for gravity flow. Lining may be an option for some drain lines, where the technician judges it suitable.

Drains must slope to work, so the choices differ from those for supply lines. The technician explains what applies to your layout, and gives upfront pricing and no hidden fees before work begins.

Repeat damp is a common reason people call.

Another Slab Leak? Call Us

What steers the choice

Where the damage is and how long the section is. The slope and the route. The flooring above and what must be opened. Whether roots or an offset are involved. Whether the problem is one failure or several. And price.

If the technician finds the drain is sound, they will say so, and point you to the next place to look. That can include the supply side, an outdoor source or a fixture.

Afterwards

After the repair, the line is tested again. Ask the technician what they found and where, and keep the record. Nobody can promise that another leak will not occur.

Workmanship on completed work is covered by a guarantee. Restoration companies handle drying and cleanup of wet flooring. For supply-line leaks, see slab leak detection.

Smell, sound and slow drains

A leaking drain line may produce a faint smell, a gurgle or a patch that stays damp near a fixture. It may also show nothing for a long time. Slow drains alone point to a blockage, which is a different problem and not something these technicians handle.

A technician separates a leak from a blockage by testing the drain system with water and watching for loss.

Access to the line

Drain lines sit at a slope under the slab, so reaching them often means a larger opening than for a supply line. The technician may use a camera to see the inside of the pipe and a test to find the point of loss.

Ask what the camera showed and whether you can see the recording.

Keeping fixtures in use

If a drain leak is suspected, it is sensible to limit use of the fixtures on the suspect line until the technician has been, since every flush or shower sends water through the damaged section. Use another bathroom if you have one.

A technician may ask you to fill a tub or run a fixture during the visit so that the line can be watched. Follow their instructions, and ask if you are unsure.

Do not pour chemicals into drains to test or clear them. It does not help find a leak.

Under-slab drain line leaks in Florida homes