Pipe Bursting

How pipe bursting works

A steel cable is threaded through the old sewer line from a pit at one end to a pit at the other. A cone-shaped bursting head, with new high-density polyethylene pipe fused to it, is pulled through by a hydraulic unit. The head splits the old clay or cast iron outward into the soil and the new pipe follows in the same alignment at the same depth. The result is a single fused length of pipe with no joints for roots to find.

When bursting is the right call

• Collapsed sections — a liner needs a host pipe to hold its shape; a collapsed run has none.
• Bellies — a low spot that holds water stays a low spot after lining. Bursting lays new pipe on a fresh bed.
• Undersized lines — bursting can upsize a 3-inch lateral to 4 inches; lining slightly reduces diameter.
• Badly deformed pipe — Orangeburg that has flattened, or cast iron with most of its bottom gone.

What the job looks like

One pit at the house or cleanout, one at the property line or the street connection, each a few feet square. Utilities that cross within a foot or two of the sewer path are located and potholed first. The pull takes an hour or two; the whole job, including fusing, connections, inspection and backfill, is usually one day.

Permits and the street

If the downstream pit is in the sidewalk, parkway or street, a right-of-way permit and restoration to city standards are required in addition to the plumbing permit. If the connection at the main is replaced, the city inspects it before the pit closes. Confirm who is handling this before work starts.