Open-trench sewer line replacement is the traditional method: excavate a trench along the path of the failed pipe, remove the old pipe, lay new pipe with proper bedding and slope, inspect, and backfill. It has been the method since municipal sewer existed and it remains the right call for a substantial fraction of failed residential laterals in Portland.
Subterra does open-trench work because it is sometimes the better choice than trenchless. When the existing line is fully collapsed, severely bellied, or below our rig's depth limit, excavation is not just preferable — it is the only option. We do the math both ways on every project and tell you which method makes more sense for your specific lateral.
When is excavation the right choice?
Excavation is the better choice when the host pipe is not viable as a path for trenchless replacement, when the yard does not contain significant landscaping or hardscape to preserve, or when the homeowner specifically prefers fully-accessible replacement for future maintenance.
- Line is collapsed or has no through-path
- Pipe-bursting requires a continuous host pipe to fracture outward; a collapse breaks that.
- Severe belly or offset
- An offset deeper than 6 inches over a short run cannot be corrected by trenchless replacement.
- Line is below our rig's 14-ft depth limit
- Some Portland mains are deeper than 14 ft; those require excavation.
- The new pipe needs a re-routed path
- Trenchless follows the old path. Excavation can take a different path.
- Short runs (20–40 ft) with simple yards
- Excavation is often $2,000–$3,000 cheaper on raw line cost when restoration is minimal.
- Property owner prefers traditional excavation
- Some homeowners want a fully accessible replacement for future-maintenance reasons. We respect that.
Our process
An open-trench residential replacement is a 2 to 5 day project. The compressed end is a 30-ft simple lateral with no driveway or sidewalk; the extended end is an 80-ft replacement with driveway saw-cut, sidewalk replacement, and full landscape restoration.
- Day 0 — Camera + permit
- Camera inspection with sonde-locator, exact depth and length mapped. Portland BDS residential sewer permit pulled.
- Day 1 — Utility locate + excavation
- 811 locate confirmed, private locate, mini-excavator opens the trench in 4-ft sections.
- Day 2 — Pipe installation
- Bedding gravel, new SDR-35 PVC or HDPE laid to proper slope (typically 1/4" per foot), house and city-tap connections made.
- Day 3 — Inspection + backfill
- Portland BDS inspector signs off on installation. Backfill in lifts with compaction.
- Day 4–5 — Surface restoration
- Concrete re-pour if driveway/sidewalk involved, topsoil and sod patches, landscape touch-up.
What it costs
Open-trench residential replacement is typically $8,400 to $48,000 depending on lateral length, depth, and surface restoration scope. Pricing transparency is non-negotiable.
| Length | Depth 5'–8' | Depth 8'–12' | + Driveway/sidewalk |
|---|---|---|---|
| 20–40 ft | $8,400 – $12,200 | $11,200 – $14,800 | +$3,200 – $6,400 |
| 40–80 ft | $13,800 – $19,600 | $17,400 – $24,600 | +$4,800 – $9,200 |
| 80–180 ft | $24,600 – $34,800 | $32,400 – $48,000 | +$7,200 – $14,000 |
Pipe materials
We replace failed laterals with one of two materials, selected by depth, run length, and project profile:
- SDR-35 PVC
- Standard residential sewer pipe. Bell-and-spigot joints with rubber gaskets. 50-year service life expected. Default for most open-trench Portland residential work.
- HDPE (SDR-17)
- Same material we use for trenchless. Heat-fused joints, no gasket failure mode. 50-year manufacturer warranty. Used on open-trench when the homeowner specifically requests it or when the run conditions favor HDPE.
Permits and inspection
We pull the Portland BDS residential sewer permit on every replacement project — homeowner does not need to interact with BDS. The permit covers excavation, pipe installation, and connection to the city tap. The inspector visits before backfill to verify slope, materials, and connection integrity. Inspection sign-off is a permanent record on the property.