A basement that floods with sewage has had the drain system work in reverse: sewage that should have gone to the main came back up the floor drain, the basement shower or the lowest toilet. Something caused that, and the cause is in the lateral, the main or the device that was supposed to stop it. The restoration crew will dry the basement; the camera inspection finds what put the water there, whether it will happen again, and what the insurer and the utility will want to see. It is done after the pumping and before the restoration is finished, because the restoration is pointless if the cause is still there.
Quick answer: after a sewage flood, the camera inspection establishes four things: whether the lateral is open or blocked and where; whether the backup came from the house’s own waste against a blockage or from the public main surcharging back up the lateral; whether a backwater valve exists and whether it held; and what condition the lateral is in after being full of sewage, including silt, debris and any joint the surcharge opened. The recording, the distances and the findings are the evidence for the insurance claim and for any complaint to the utility.
Blockage or surcharge
The first question, because the remedies are opposite. A blockage in the lateral means the house’s own waste backed up against roots, grease, a collapse or a wad, and the fix is to clear and repair the lateral. A surcharge means the public main filled, usually in heavy rain, and pushed sewage from the street up into the house; the lateral may be perfectly sound and the fix is a backwater valve and a complaint to the utility. The camera tells them apart: a blockage is visible at a distance with dry or draining pipe beyond; a surcharge leaves a clear lateral, often with a tide line of debris on the crown and flow marks pointing toward the house. The timing helps too: a surcharge coincides with a storm. The multiple fixtures guide and reading standing water cover both pictures.
The backwater valve
If the house has one, the inspection includes it, at the access cover and by camera from the house side. A flap held open by a wad of wipes or a stone is the most common reason a valve did not stop a surcharge, and finding it is the difference between replacing the valve and clearing it. If the house has no valve and the flood was a surcharge, the inspection’s main recommendation is to install one. The backwater valve guide covers the inspection and the failures.
The lateral after the flood
A lateral that was full of sewage for hours has a bed of silt and debris along its length, and the structural inspection waits until it is jetted. After cleaning, the camera looks for what the pressure of a surcharge may have done: joints opened, cleanout caps lifted, and in old pipe cracks that let water out under head. It also looks for the defect that caused a blockage, if that was the cause, and for anything that will cause the next one. The flood damage guide sets out the full order of work.
How the water got in
A surcharge enters through the lowest open drain, which the inspection identifies. A blockage backs up through the lowest fixture above it. But a stormwater connection, a downspout or a sump tied into the lateral, can fill the lateral in a storm and flood the basement without any surcharge at all, and the camera in the lateral during the next rain finds it. The stormwater connection guide covers that case, which is often the cheapest flood to prevent.
The evidence
Insurers ask whether the backup was a sewer backup, which is often a separate coverage, and whether it was caused by the homeowner’s failure to maintain the line or by the utility’s main. The camera recording with distance on screen, the stills of the cause, the date, the weather and the condition of the backwater valve answer those questions. A utility complaint about a surcharge needs the same evidence plus the timing against the storm. Inspection for warranty and insurance claims covers what each party wants to see.
Safety
A basement after a sewage flood is contaminated and may hold sewer gas. Pump and ventilate before anyone works in it, confirm the power is off where water reached outlets, wear protection, and treat the camera equipment as contaminated until it is cleaned. Hygiene after sewer camera work covers the cleaning.
What to record
The date and the weather. The lowest fixture that overflowed. Whether the lateral was blocked and where, or clear. The flow direction and any tide line. The backwater valve’s presence and state. The silt bed before cleaning and the findings after. Any stormwater connection. Dated footage of each stage. That record is the claim, the utility complaint and the specification for whatever is installed or repaired to stop the next one.
Common questions
Was the flood my fault or the city’s?
A blockage in the lateral is the owner’s; a surcharged main is the utility’s. The camera shows which.
Will insurance want the video?
Usually. It is the evidence of cause, which decides coverage.
How do I stop it happening again?
For a blockage, repair the defect. For a surcharge, a backwater valve. For a stormwater connection, disconnect it.
Related guides
See basement floor drain backups, the best sewer cameras for restoration work, and inspection in tenant and landlord disputes.