Trenchless sewer replacement is a pulling-rig method for installing new sewer pipe along the path of the old failed pipe — without trenching the yard between the two ends. The new pipe enters the ground at the cleanout end, pulls along the old pipe path, and emerges at the city-tap end. Everything between those two access pits stays where it is.
There are two distinct trenchless methods we use. Pipe-bursting is the primary one — a pneumatic bursting head is pulled through the old pipe, fracturing it outward into the surrounding soil and simultaneously pulling new HDPE pipe into the void behind it. Cured-in-place pipe (CIPP) lining is the secondary method — an epoxy-saturated liner is pulled through the old host pipe, inverted, and cured into a new structural pipe inside the old one.
Subterra primarily does pipe-bursting. We offer CIPP lining on a case-by-case basis — some pipe conditions favor lining over bursting, particularly when the host pipe is structurally sound but has localized failures or root intrusion at joints.
The method itself is not new. Pipe-bursting has been in residential use in the Pacific Northwest since the late 1990s. What is specific to Subterra is that we own the rig — a TT Technologies Grundocrack 800G pneumatic bursting system with a 6-ton TRIC Tools hydraulic pulling unit, mounted on a 2017 Peterbilt 348 chassis — and Marina Sundström-Reyes (OR PJ-CB #29841, civil engineer) runs every project personally.
When is trenchless the right choice?
Trenchless is the right call when restoration cost — replacing what excavation would destroy — exceeds the price premium of the trenchless method. Specifically, trenchless is the right choice when any of the following are true:
- Mature landscaping over the line
- Established trees, large shrubs, mature lawn that you can't replace cheaply or quickly.
- Mature trees with extensive root systems
- You can't disturb the root pan without putting the tree at risk.
- Driveway, patio, or hardscape over the line
- Saw-cutting and re-pouring concrete adds substantial cost.
- Line under city sidewalk or public right-of-way
- Portland BDS prefers trenchless under public right-of-way to minimize sidewalk replacement.
- Multi-story home with constrained excavation access
- Side yards too narrow for excavator access.
- Line crosses under a building addition
- Trenchless preserves the addition.
When is trenchless NOT the right choice?
Trenchless is not always the answer. We will tell you when excavation is the better call, even though our rig is sitting at the yard. Specifically:
- Line is severely bellied
- An offset deeper than 6 inches over a short run cannot be fixed by trenchless replacement — the new pipe will follow the same belly.
- Line is collapsed
- No through-path for the pulling head means no trenchless. We have to excavate.
- Line is below 14 ft
- That is the depth limit for our rig and our crew's safe-excavation envelope.
- The line needs a re-route, not a replacement
- If the new pipe needs to take a different path (around a new addition, away from a tree pan, etc.), trenchless cannot do that.
- Property owner prefers traditional excavation
- Some homeowners prefer an open trench for future-access reasons. We respect that.
What it costs
Trenchless replacement in Portland is generally priced by lateral length and depth, with a fixed-overhead component for rig mobilization and permit. Pricing transparency is non-negotiable for us. Here is the honest range as of 2026 for residential trenchless and excavation:
| Length | Excavation | Trenchless | Net Savings |
|---|---|---|---|
| 20–40 ft | $8,400 – $13,800 | $11,200 – $14,800 | $0 – $4,000 |
| 40–80 ft | $13,800 – $24,600 | $14,800 – $22,400 | $0 – $6,200 |
| 80–180 ft | $24,600 – $48,000 | $22,400 – $34,800 | $4,000 – $18,000 |
| Restoration | HIGH (landscaping) | MINIMAL (2 pits) | $3,000 – $15,000 |
The honest math: trenchless is not always cheaper on raw line cost. It is almost always cheaper once you add back the cost of restoring the trench — replanting mature shrubs, re-pouring a driveway, replacing a sidewalk, redoing landscape lighting. We do the math both ways and tell you which is the better choice for your specific yard.
Our equipment
The trenchless rig is the most specialized piece of equipment Subterra owns. The pneumatic system is a TT Technologies Grundocrack 800G — German-engineered, 800 ft-lb impact rating, pulled through old pipe by cable while delivering controlled pneumatic strikes that fracture the host pipe outward.
The pulling unit is a TRIC Tools 6-ton hydraulic puller mounted on the rear deck of a 2017 Peterbilt 348 chassis. The 6-ton rating is sufficient for residential lateral pulls up to about 180 ft of 4"–8" HDPE through cast iron, clay tile, or Orangeburg host pipe.
We carry pulling heads in 4", 6", and 8" diameters and stock SDR-17 HDPE pipe on the truck. SDR-17 is the industry-standard residential sewer HDPE — pressure-rated, flexible enough to follow the host-pipe path, with a 50-year manufacturer warranty.
A typical trenchless day
A residential trenchless project is almost always completed in a single day. Here is what the day actually looks like.
- 7:00 AM — Arrival, utility locate, pit-marking
- Confirm 811 utility locates (called 72 hours prior), do a private locate for any unmarked utilities, mark the two access pits with paint.
- 8:00 AM — Hand-dig access pits
- Two 3'×3' pits at the cleanout and city-tap ends. Depth typically 5–9 ft. Hand-shoveled — no machine.
- 10:00 AM — Camera, then insert pulling cable
- Confirm the path is clear of obstructions, then feed the pulling cable through the old pipe from one pit to the other.
- 11:00 AM — Connect HDPE
- Fuse HDPE sections at the yard if not pre-fused, attach pulling head to one end, attach HDPE behind the head.
- 12:00 PM — Begin pull
- Hydraulic pull starts. Pneumatic head fractures the old pipe. New HDPE follows the path.
- 3:00 PM — Pull complete
- Bursting head emerges at the receiving pit. New HDPE in place along the full length.
- 3:30 PM — Connections
- Fernco transition couplings at the cleanout end; saddle-and-strap at the city-tap end.
- 5:00 PM — Backfill + surface restoration
- Crushed rock to 18", native soil above, sod patches over the pits.
- 6:00 PM — Client walkthrough, leave job
- Post-install camera check is scheduled for 30 days later (no charge).