A bursting head, slightly larger than the old pipe, is pulled through the lateral by a cable from a pit at the far end. As it moves, it fractures the old clay or cast iron and pushes the pieces into the surrounding soil, while the new pipe attached behind it follows into the same space.
The result is a new lateral without digging the full length of the yard. Typically there is an entry pit and an exit pit, often one near the house and one near the street connection. Because the new pipe follows the old route, it inherits the old path's slope, which matters if the existing line has a belly.
Pipe bursting compared with the alternatives
| Factor | Pipe bursting | Lining | Open trench |
|---|---|---|---|
| Result | New pipe in the old path | New pipe inside the old pipe | New pipe in a new trench |
| Excavation | Entry and exit pits | Often access points only | Full length of the run |
| Can fix a sag | Not reliably | No | Yes |
| Handles a collapsed pipe | Sometimes, if the head can pass | No | Yes |
| Pipe size change | Can go up a size in some cases | Slightly smaller | Any size allowed by code |
Site conditions to check first
Bursting pushes fragments outward, so what lies near the old pipe matters.
- Gas lines, water lines and other utilities marked before work starts
- Distance between the old lateral and those utilities
- Room for an entry pit and an exit pit, and what surface they will cut
- Foundation, walls or tree roots close to the pipe route
- Branch connections along the run that will need their own access
Sequence of a typical bursting job
- Before
- Camera inspection, utility locating and a plan for both pits.
- Day of work
- Pits dug, cable threaded through the old pipe, new pipe staged.
- The pull
- Bursting head drawn through, new pipe following into place.
- Connections
- New pipe tied to the house drain and the city connection with approved fittings.
- Before backfill
- Camera run through the new pipe and any required inspection.
Questions for a bursting proposal
- Where will the entry and exit pits be, and what surfaces will they disturb?
- Does the existing line have a sag that the new pipe will follow?
- How close are other utilities to the pipe route?
- What size and type of new pipe will be installed?
- Who arranges permits and any city inspection? Check with the city if unsure.
Common questions
Is pipe bursting the same as trenchless lining?
Both are called trenchless, but bursting installs a new pipe in place of the old one, while lining builds a new pipe inside the old one.
Can pipe bursting go under a driveway?
Often yes, as long as the pits can be placed on either side and nothing in the path would be harmed by the expanding head.
Does bursting fix roots permanently?
It replaces the jointed old pipe with new pipe, which removes the joints roots were using along that run.
General information for Placentia, not a quote or professional advice. In an emergency, call 911.