What We Found Beneath the Concrete
The reported sink backup was only part of the problem. The exposed drain line revealed why the laundry could appear to drain even though the underground piping had failed.
- Location: Moore, Oklahoma
- Reported symptom: recurring kitchen sink backups
- Laundry appeared to operate normally
- Prior proposal: $15,000 to reroute the kitchen drain outside
- Finding: rotted-out underground drain pipe
- Hidden discharge: washing-machine wastewater beneath the slab
- Work performed: concrete removal, excavation, and failed-pipe removal
Why the Laundry Still Seemed to Work
A washer can pump water out of its tub even when the connected drain line is broken. On this job, that water was escaping beneath the slab instead of staying inside the sewer piping. An empty washer tub was not proof of an intact drain.
The dryer was also working, but dryer operation does not verify the condition of the laundry sewer line. The important clue was the path taken by the washing machine's wastewater.
Why the $15,000 Reroute Proposal Needed a Closer Look
An exterior reroute can be an option for some properties, but the scope needs to account for every affected connection. Moving only the kitchen drain would not, by itself, correct a separate laundry discharge beneath the slab.
The $15,000 figure was the homeowner's prior quote for a different proposed scope. It is not our repair price or a claim of savings. The lesson from this job is to identify the failed piping and connected fixtures before choosing the repair route.
Can Sewer Flies Point to a Broken Pipe Under the House?
Yes, flies can be a clue worth investigating, especially when they keep returning alongside sewer odors or drain trouble. They do not prove that a pipe is rotted. Drain flies can breed in organic buildup inside otherwise intact drains, as well as around sewer leaks.
Small flies are not all the same species. University of Maryland Extension notes that very large numbers of phorid flies on a building's first floor may indicate a broken drain or sewer line beneath it. Identifying the flies and locating their breeding source helps determine whether drain cleaning, a plumbing investigation, or both are needed.
If flies persist after accessible drain buildup is removed, have the source investigated. A leaking underground pipe needs its plumbing defect corrected and affected material addressed; treating adult flies alone does not remove the breeding source.
How We Accessed and Removed the Rotted Pipe
For this job, we accessed the drain from inside the house. Our crew removed the concrete over the affected route, excavated the buried piping, and removed the rotted pipe.
Opening the slab made it possible to expose the damaged line directly. That work addressed the failed underground piping rather than treating the kitchen backup as an isolated clog.
- Identified the rotted pipe and hidden laundry discharge
- Removed concrete to access the underground drain route
- Excavated around the affected piping
- Removed the rotted pipe from the exposed trench
This project documents the discovery, concrete removal, excavation, and removal of the failed pipe. The general repair guidance below explains the additional steps involved in completing an under-slab sewer repair.
How Do You Fix Sewer Pipes Under a Slab?
Start by locating the defect and identifying which fixtures connect to the affected line. A plumber may use camera inspection, locating equipment, and appropriate testing, depending on access and the condition of the pipe. The findings determine whether direct access, rerouting, or a suitable trenchless method makes sense.
With direct access, the crew plans the slab opening around buried utilities and structural conditions, removes the necessary concrete, excavates the line, and removes failed piping. Replacement piping needs appropriate connections, support, and drainage slope. Required testing and inspections should happen before the repair is covered, followed by suitable backfill, compaction, and slab restoration.
Pipe lining is not suitable for every failed drain. Missing pipe, collapse, poor alignment, or unsuitable connections can require excavation or a different repair method. The condition of the line determines the options.
Questions About Rotted Sewer Pipes Under a Slab
Do sewer flies mean I have rotted sewer pipe under my house?
They can signal a hidden sewer leak, but flies alone do not prove a pipe is rotted. Drain flies also breed in organic buildup inside intact drains. Persistent flies, especially with sewer odors or recurring backups, warrant an investigation of the breeding source and plumbing. Very large numbers of phorid flies can be associated with broken drain or sewer lines beneath a building.
How do you fix sewer pipes under a concrete slab?
Locate the damage and connected fixtures first. For a direct-access repair, a qualified crew opens the necessary concrete, excavates, removes the failed pipe, and installs properly supported replacement piping with suitable slope and connections. Testing and required inspections come before backfill and slab restoration. Rerouting or trenchless repair may be alternatives when the pipe condition and layout allow them.
Why does my kitchen sink back up while my washing machine still drains?
The fixtures may have different drain paths or a blockage may affect only one branch. A broken pipe can also let washer water escape into the soil, making it look as though the laundry drain works. That is what we found on this job. A working washer does not rule out an underground sewer failure.
Will rerouting the kitchen drain fix a leaking laundry sewer pipe?
Only if the repair scope also corrects the affected laundry connection and failed piping. A kitchen-only reroute does not automatically stop laundry wastewater from leaking beneath the house. Ask which fixtures and pipe sections are included before comparing proposals.
Can you repair a rotted sewer pipe without breaking concrete?
Sometimes. Rerouting or an appropriate trenchless method may reduce interior concrete removal, but neither works for every layout or pipe condition. Severely deteriorated, missing, or collapsed piping can require excavation. Inspection is needed before choosing a method.
Will drain cleaning fix a rotted sewer pipe?
Cleaning can remove a blockage in a serviceable pipe, but it cannot replace missing pipe walls or seal a failed line. Repeated backups after cleaning can justify further inspection for deterioration, damaged connections, or other defects.
How much does under-slab sewer pipe repair cost?
Cost depends on the location and length of damaged pipe, access, depth, connected fixtures, repair method, and concrete or flooring restoration. The $15,000 mentioned in this project was another company's kitchen-reroute proposal, not a price for our work or a standard under-slab repair price. An inspection and written scope are needed for an accurate estimate.
Can I keep using the washer if it drains beneath the slab?
Stop using the affected washer and other fixtures connected to the failed line until a plumber advises that they can be used. Continuing to discharge wastewater adds moisture and contamination beneath the house even when nothing backs up into the room.
Recurring Kitchen Backups or a Suspected Under-Slab Sewer Leak?
Tell TradeStrong which fixtures back up, which still appear to drain, and whether you have noticed sewer odors or persistent flies. We serve Moore and the Oklahoma City metro and can investigate the drain problem and explain repair options based on what we find.
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