Last reviewed and updated: 2026-09-24
Sewer and drain lines are not pressurized, so they only leak while water is running through them. That rules out the acoustic listening used for supply leaks. Instead, sewer leaks are found with video camera inspection, smoke testing and dye testing. In Marietta the most common causes are root intrusion into older clay and cast iron laterals, joint failure, and pipe bellies caused by ground movement in Georgia clay soil.
Drain lines only leak while water runs, so they need a camera inspection and smoke testing rather than acoustic listening. Root intrusion is common under Marietta's mature canopy, particularly around East Cobb.
Signs of a sewer or drain line leak
- A persistent sewer or sulphur smell indoors or in the yard
- Repeated slow drains or backups across multiple fixtures, not just one
- Gurgling from drains or toilets when other fixtures run
- A patch of lawn that is unusually lush, soggy or sunken along the lateral route
- Damp or staining at floor level with no supply leak found
- Increased pest or insect activity around one area of the property
Why drain leaks are harder to find
A pressurized supply line leaks constantly and makes noise, which is what acoustic equipment listens for. A drain line sits empty most of the time. It leaks only in the seconds while waste water passes the defect, and it makes almost no sound doing it. That is why the toolkit is different.
How they are found
| Method | What it finds |
|---|---|
| Video camera inspection | The condition of the line from inside: cracks, offsets, root masses, bellies, collapses. Also maps depth and location. |
| Smoke testing | Non-toxic smoke pushed into the system escapes through any defect, revealing cracks and broken vents that a camera can miss. |
| Dye testing | Confirms which fixture or line feeds a suspected leak point. |
| Hydrostatic testing | Isolates and fills the drain system with water to test whether it holds, proves a leak exists before locating it. |
| Line locating | Maps the exact route and depth of the lateral so excavation is targeted. |
Root intrusion in Marietta
Marietta's mature tree canopy is one of the best things about the area and one of the hardest things on its sewer laterals. Roots seek moisture, find it at the joints of older clay and cast iron pipe, and grow into the line. Once inside they trap solids, which is why the first symptom is usually repeated backups rather than an obvious leak. Cutting the roots clears the blockage but not the defect that let them in, so recurring backups on the same line point to a structural repair rather than another cleaning.
Repair options
- Spot repair: excavate and replace the failed section where the defect is isolated.
- Pipe lining (CIPP): a resin liner cured in place inside the existing pipe, sealing joints and root entry points without a trench.
- Pipe bursting: a new line pulled through the old one, which is fractured outwards. Trenchless, and suitable when the old pipe is beyond lining.
- Full replacement: where the line has collapsed, has multiple bellies, or is at the end of its life.
Frequently asked questions
What are the signs of a sewer line leak?
A persistent sewer or sulphur smell indoors or outside, repeated slow drains or backups across several fixtures, gurgling from drains and toilets, a patch of lawn that is unusually lush, soggy or sunken along the lateral route, and increased insect activity in one area.
Why can't acoustic equipment find a sewer leak?
Because drain lines are not pressurized. Acoustic detection listens for the hiss of water escaping under pressure, which a drain line does not produce. Drain leaks are found instead with camera inspection, smoke testing, dye testing and hydrostatic testing.
What is a sewer camera inspection?
A camera on a flexible rod is fed through the line to show its condition from the inside, cracks, joint offsets, root intrusion, bellies where the pipe has sagged, and collapses. It also maps the line's route and depth so any excavation is targeted rather than exploratory.
Why do tree roots get into sewer lines in Marietta?
Roots seek moisture and find it escaping at the joints of older clay and cast iron laterals. Marietta's mature tree canopy sits above a lot of pipe from that era. Once roots are inside they trap solids, so the first symptom is usually repeated backups rather than a visible leak.
If cleaning fixes the backup, do I still have a problem?
Usually yes. Cutting roots clears the blockage but not the defect that let them in, so they grow back. Repeated backups on the same line point to a structural repair, lining, bursting or replacement: rather than another cleaning.
Can a sewer line be repaired without digging up the yard?
Often, yes. Cured-in-place pipe lining installs a resin liner inside the existing pipe, sealing joints and root entry points. Pipe bursting pulls a new line through the old one. Both are trenchless, though a collapsed or badly deformed line may still need excavation.
What is a smoke test?
Non-toxic smoke is pushed into the drain system under low pressure. It escapes anywhere there is a defect: a cracked line, a broken vent, a failed seal, showing the problem visibly at the surface. It is useful for finding odor sources a camera cannot see.