On most lots the sewer lateral leaves the house near the front and runs to the street, which is also where the driveway goes, so the lateral spends much of its length under the one surface on the property that carries trucks. When the driveway is replaced, the lateral beneath it takes the worst day of its life: the old slab is broken out with a breaker, the base is compacted with a plate or a roller, a loaded concrete truck or a paver sits on it, and the new slab is poured on top. A lateral that was shallow, old or poorly bedded often does not survive it, and the symptoms arrive months later when nobody connects a slow drain with the new driveway.
Quick answer: paving damages the lateral by crushing it under equipment, shearing joints as the base is compacted unevenly, and settling it where the old slab’s removal disturbed the bedding. The camera finds a crushed or deflected section, offset or separated joints, and a belly, all under the new driveway, with the sonde locate landing on the slab. Repair means cutting the new driveway, which is why the inspection before paving and the simple precautions during it are worth far more than they cost.
How the damage happens
A breaker removing the old slab sends shock through the base to the pipe. A plate compactor or a roller on the new base compresses the soil over the pipe more than the soil beside it, dropping the pipe and shearing the joints at the edge of the driveway. A loaded concrete truck, far heavier than anything the driveway will carry in service, parks over a line with two or three feet of cover. Excavation for a thicker base or for drainage cuts into the trench. And a new slab is often poured directly on the pipe where the base was thin. Any of these can crush plastic, crack clay or cast iron, or open a joint. The settlement guide covers the load mechanics.
What the camera finds
A deflected or crushed section with the opening gone oval or flat, in plastic. A circumferential or longitudinal crack, in clay or cast iron. An offset or separated joint at the driveway edge, where compaction changed. A belly under the slab where the pipe dropped. Fresh damage with clean edges and no root growth. Sometimes concrete or base material inside the pipe where a crack let it in. The sonde locate at each defect lands on the new driveway, which is the confirmation and the start of an uncomfortable conversation with the paving contractor. The ovality guide and the crack pattern guide describe the findings.
Before the work
Camera the lateral with the counter running and a sonde in the head, and locate it every 10 ft under the driveway’s footprint. Paint the route. Note the depth estimates. Give the paving contractor the route and the depths and ask for the line to be protected: steel plates over it when the concrete truck comes, no breaker directly above it, compaction with a lighter machine over the pipe, and extra base thickness so the slab does not sit on it. Keep the footage as a baseline. This takes an hour and is the single most valuable hour in the whole project. The pre-paving inspection guide walks through it.
After the work
Camera the lateral again within a few weeks, before any symptoms, while the contractor is still on the job or at least answerable. Compare with the baseline. A new defect under the driveway is the contractor’s; an old one is not. If there is no baseline, the comparison is harder but a fresh crush or a clean-edged crack is still recognisable. Re-inspecting after work covers the follow-up.
Repair under a new driveway
The options are to cut the slab and dig, which ruins the new driveway at the repair point; to line the lateral, if the damage is cracks and offsets rather than a crush, which avoids the dig; or to burst the lateral, if it is continuous enough, which replaces it with one small pit at each end. A crushed plastic section cannot be lined and must be dug. The camera findings decide, and repair under a driveway compares the options.
What to record
Before: the route, the depths, the condition, dated. After: every new finding with its distance and surface mark, dated, with the before footage for comparison. A paving contractor faced with before-and-after footage of a crushed lateral under their new slab has little to argue about; one faced with a complaint and no footage has a great deal.
Talking to the paving contractor
Most paving crews have never been told where a lateral runs and are glad to be told. Give them the painted route, the depth estimates and a copy of the baseline footage, and ask for three things in writing: plates over the line for the concrete truck, no breaker directly above it, and a lighter compactor over the marked strip. A contractor who agrees to that has taken on the responsibility; one who refuses has told you something useful before the work starts.
Common questions
Can paving a driveway break a sewer line?
Yes, and it is one of the most common causes of sudden lateral damage in an established house.
Who pays for the repair?
If the line was marked and the contractor ignored it, the contractor. If it was not marked, usually the owner. The before-and-after footage decides.
Can the lateral be repaired without cutting the driveway?
By lining or bursting, if the damage is cracks or joints rather than a crush. A crushed section needs a dig.
Related guides
See locating a sewer line under concrete, locating under asphalt and pavers, and the best sewer cameras for excavation planning.