A new house’s sewer lateral was laid early in construction, buried, driven over for months by every truck on the site, and connected to fixtures by a crew working to a schedule. It is plastic and will last a century if it was installed well. Whether it was is unknown until someone looks, and the only time looking is free of consequence for the owner is while the builder’s warranty runs. A camera inspection at the walkthrough or before the warranty ends finds the installation faults, puts them on the builder’s list and leaves the owner with a baseline recording of a sound line.
Quick answer: inspect a new lateral from the exterior cleanout to the main with the counter running, a sonde in the head and the recording on. Look for construction debris, a belly or flat run from poor bedding or wrong slope, a dry joint at any hub, a crushed or deflected section where site traffic crossed the trench, a protruding tap at the main, and a route that passes under something it should not. Locate anything found and give the builder the recording, the distances and the marks. Keep the recording whether or not anything is found.
What goes wrong in a new lateral
Debris. Mortar, concrete slurry, drywall compound, gravel and offcuts end up in the line during the build and sit in the first low spot. Bedding and slope. A trench backfilled without compaction settles into a belly; a trench dug to the wrong depth gives a flat or back-graded run. Dry joints. A hub pushed together to check alignment and never cemented. Site traffic. Concrete trucks and excavators crossing a shallow trench crush or deflect the pipe. The tap. The connection at the main, cut by the lowest bidder, protruding into the main or made without a proper fitting. Routing. A lateral under a footing, a tree pit or a future driveway. Each is specific and each is found by camera. The post-2000 house guide describes them in detail.
What the camera shows
A new plastic pipe should look new: smooth, round, with a cemented ring at every hub and a steady fall to the street. Grey slurry or a bed of grit on the invert is debris. Standing water with a start and an end is a belly; a long shallow film is a flat run. A hub with a dark gap around the pipe is a dry joint. An oval opening is a deflected section, and a sonde locate at it usually lands on the driveway or a tyre track. A pipe end standing into the main is a bad tap. The ovality guide and the ABS guide show the plastic-specific pictures.
When to inspect
At the pre-closing walkthrough, before the owner takes possession, so that findings go on the punch list. Or, if that is missed, before the builder’s warranty expires, which is often one year for workmanship. A finding inside the warranty is the builder’s to fix; the same finding a month after is the owner’s. New-build walkthroughs covers the timing in detail.
Dealing with the builder
Give the builder the recording with distance on screen, the stills and the surface marks. A belly at 28 to 41 ft with three inches of standing water, located and painted, is a warranty item that is hard to dispute; “the drain seems slow” is not. Most builders fix a documented drain fault without argument because the alternative is a warranty claim with video evidence. Ask for a camera pass after the fix, and keep both recordings. Inspection for warranty and insurance claims covers the evidence.
The baseline
A recording of a sound new lateral, dated, with the route traced and the depths noted, is the house’s sewer file. Any later inspection is compared with it, any later damage from paving, landscaping or a neighbour’s excavation is dated by it, and a buyer years later will be glad of it. It costs an hour and it is the cheapest sewer document the house will ever have. Footage retention covers keeping it.
Equipment
A 23 mm reel with a sonde and a counter, and a receiver for the locates. A new lateral is plastic, so the sonde is the only way to trace it, and the plastic pipe locator guide explains why. A home inspector doing the walkthrough can add the sewer scope if they carry a sonde camera; otherwise a separate provider. The questions to ask apply.
What to record
The date, the entry point, the route and depths, every finding with distance and surface mark, stills, the builder’s response, and the post-fix recording. A clean result is recorded just as carefully as a faulty one.
Reading the tap at the main
The connection to the street main is the one joint on a new lateral the builder did not make themselves; it was cut by the utility or a tapping contractor, and it is worth pushing the camera all the way to it. A proper tap is a smooth opening in a fitting; a bad one has the lateral protruding into the main or a ragged hole around it. A protruding tap on a new lateral is a warranty item for whoever made it, and it is also the reason the first blockage will happen at the street rather than the house.
Common questions
Why would a brand-new sewer line have problems?
Because installation faults are common and invisible: debris, poor bedding, dry joints and site traffic. The pipe is fine; the trench may not be.
Will the builder fix what the camera finds?
Inside the warranty and with video evidence, usually. Document it and ask for a camera pass after the fix.
Is the inspection worth it if nothing is found?
Yes. The baseline recording is the house’s sewer file for the next thirty years.
Related guides
See settlement after construction, the best sewer cameras for PVC pipes, and sewer scope inspection when buying a house.