ABS, the black plastic drain pipe, replaced cast iron and clay in much of North America from the late 1960s through the 1980s, and in many regions it is still the standard material for the drain, waste and vent system inside the house and sometimes for the lateral outside it. It does not corrode, it does not scale and roots cannot get through the wall. When it fails, it fails at the joints and at points where it was crushed, bent or badly supported, and there is one period, the mid-1980s, when some batches of ABS were made from recycled resin that turned brittle and cracked. A camera pass through an ABS line is therefore a search for a handful of specific things rather than a general survey.
Quick answer: ABS shows on camera as a smooth, matte black or very dark grey wall with solvent-welded joints that appear as a slight ring or no visible joint at all. The common defects are a joint that was dry-fitted and never glued and has pulled apart, a bell crushed during backfill, a section flattened by load, a belly where the pipe was not bedded, a saddle tee cut into the pipe badly, and in brittle batches a crack that runs from a fitting. Most ABS defects are spot repairs; the pipe between them is usually fine.
Recognising ABS
Black and matte, with none of the gloss of clay or the rust of iron. Joints are solvent-welded, so a sound joint shows as a faint ring where the pipe enters the fitting hub, or as nothing. Fittings are recognisable as moulded shapes: a long-sweep elbow, a wye, a sanitary tee. Printing on the pipe is sometimes visible as a lighter stripe. PVC is the same shape in white or grey; the colour is the difference, and the PVC guide covers the near-identical inspection of that material.
The never-glued joint
ABS joints are made by applying solvent cement to the pipe and the hub and pushing them together. A joint that was dry-fitted to check alignment and then never cemented holds for years by friction and the soil around it, then pulls apart when the ground moves. On camera it shows as a hub with a dark gap around the pipe, often with the pipe end visible a short distance inside the hub, and sometimes with roots or soil in the gap. It is the single most common ABS defect in a lateral and it is a spot repair. The separated joint guide covers how it looks when the pipe has left the hub entirely.
Crushed bells and flattened sections
ABS is tough but it is not rigid. A hub crushed by a rock in the backfill shows as an oval or dented opening at the fitting. A section flattened by a vehicle or a footing shows as the pipe going oval or slot-shaped and the camera head slowing or stopping. Both are load findings and both are spot repairs, usually at a point directly under whatever caused them. A sonde locate at the crushed section often lands on the driveway edge or the footing that explains it. Driveway and heavy equipment damage covers the usual cause.
Bellies
ABS laterals from the 1970s were often laid in trenches that were backfilled without proper bedding, and bellies are common. The camera shows standing water that begins and ends at defined points, with sediment collected in it, in an otherwise sound pipe. A belly in ABS is the same repair decision as in any material: shallow and dry between uses, monitor; deep, debris-filled and causing backups, excavate and re-bed. The belly guide walks through it.
Bad saddles and brittle batches
A saddle tee is a fitting strapped onto the outside of a pipe with a hole cut through the wall to connect a branch. Cut badly, the hole is ragged and the branch protrudes into the main pipe, catching paper and the camera head. On camera it shows as a rough opening in the side wall with a pipe end visible inside the bore. Brittle ABS, from recycled-resin batches made mainly in the mid-1980s, cracks at fittings and along the pipe without any load to explain it; on camera the cracks are fine, straight and often radiate from a hub. A house from that period with cracking ABS at several fittings has a material problem, not a local one, and the fix is replacement of the affected runs.
Inspecting ABS
Dim the LEDs; a black wall absorbs light and full power shows only the nearest few inches, but too little light hides the gap at a dry joint. Slow at every fitting hub and look for the ring. Watch the pipe shape for ovality. Note the distance at any belly’s start and end. And remember that ABS cannot be located from the surface without a sonde in the head, so a camera with a 512 Hz transmitter is the tool if any finding may lead to a dig. The plastic pipe locator guide explains why.
Common questions
Does ABS pipe need replacing?
Not as a material. Specific defects, a dry joint, a crushed bell, a belly, are spot repairs. Brittle 1980s batches with multiple cracks are the exception.
Can roots get into ABS?
Only through a failed joint or a crack. The wall itself is impervious.
Can ABS be lined?
Yes, if the pipe is round and continuous. A crushed section or an open joint needs a spot repair first.
Related guides
See sewer line problems in houses built 1975 to 2000, cast iron vs PVC on camera, and the best sewer cameras for residential inspection.