Can a sewer camera find water line or slab leaks?

It sees the inside of drain and sewer pipes: sewer laterals, building drains, and the lines under sinks, tubs and floor drains. Wikipedia says the camera is fed through an access point on the property, such as a drain cover or cleanout, and describes drain cameras as tools used to detect problems such as "debris buildups, collapsed pipe sections, root infestations, and pipe offsets." NASSCO adds that CCTV can be used to determine structural condition, locate service laterals, identify infiltration and inflow, and locate obstructions like roots, grease and debris.

NASSCO also says CCTV inspection is used on pipelines such as gravity flow sewers and water mains. Those are utility-scale pipes. The supply piping inside a home or small commercial building is a different system: narrow, sealed and full of water under pressure, with no cleanout or drain cover to feed a drain camera through. So for a slab leak, a drain camera is generally not the tool.

Usually the first step is the water meter. The City of Chandler's leak guide gives the test: turn everything that uses water off, then check the meter. "With all water turned off in the house, there should be no movement of the small pointer or any of the dials on the meter." If it moves, water is going somewhere. Chandler also says leaks after the meter on private property are the homeowner's responsibility, and it warns that meter movement "can also be caused by things like an automatic pool filler, a leaky irrigation valve, or an evaporative cooler," so rule those out first.

After the meter, the search narrows to the pipe itself. Wikipedia's overview of pipeline leak detection lists several general methods, including hydrostatic testing, infrared, and acoustic technologies. Three of them show how a hidden leak can be located without opening the floor:

• Acoustic listening. Wikipedia says "escaping liquids create an acoustic signal as they pass through a hole in the pipe."
• Infrared and thermal imaging. Wikipedia says the surface temperature patterns above a buried pipeline "can help show where pipeline leaks and resulting erosion voids are forming," because water that leaks out has a different thermal conductance than dry soil.
• Pressure testing. Hydrostatic testing is one of the methods that overview names. In a home it means isolating a section of supply plumbing and watching whether the pressure holds.

That overview covers pipelines in general, not slabs specifically, so treat it as background on how the methods work. Our pages on how plumbers find hidden leaks, signs of a slab leak in Arizona and the water meter leak test go deeper. HQ's leak detection page covers what we do.

When the leak is on the waste side. A cracked, broken or separated sewer pipe can leak sewage into the soil, and groundwater can get in through the same openings. InterNACHI's sewer scope standard lists visible cracks, a broken line or pipe, and a separated or disconnected line or pipe among the defects an inspector must report. NASSCO's PACP grading matrix has codes for cracks, fractures, holes and broken pipe, and for infiltration ranging from a weeper to a gusher. Wikipedia notes that vitrified clay, common in older sewers, is more brittle than plastic, which "can lead to cracking of the pipes and leakage." The camera may show those defects where the view and access permit. Signs that point to a drain-side problem include:

• A wet spot or sunken patch over the sewer route, but a water meter that does not move with everything off.
• Sewer odor, gurgling or backups.
• A wet area where a drain line runs under the slab.

A meter reads water coming into the property, so a leak in a drain line generally does not move it. That is why the meter test is a good first filter. It is a rule of thumb, not a promise about your building, so check with a plumber if the signs are mixed.

Sometimes it helps in a roundabout way. A plumber may run a camera in the drain line near a wet area to assess visible waste-pipe defects before choosing further supply or drain tests. A camera cannot rule out every hidden waste leak. That can save you from paying for slab work on the wrong pipe. But a drain camera does not find a pressurized leak, and it should not be sold as if it does.

Start with the meter test. If the meter moves, call a plumber for leak detection. If the meter is still and you have odor, gurgling, backups or a sunken area over the sewer, ask for a camera inspection of the drain line. If both could be true, a plumber can do both in one visit.

HQ handles both kinds of hidden leak. We are licensed and insured, run 24/7 emergency service, and give free estimates and upfront pricing. See leak detection or sewer repair.

For the current inspection service, see HQ’s sewer camera inspections.