For plumbing companies · Subcontract the excavation
Under-Slab Tunneling for Plumbers in San Antonio & Austin
When there's a broken sewer line, a slab leak, a belly in the drain, or a full cast-iron replacement under a slab, the pipe repair is the easy part — the digging is what eats the day. Motmot tunnels the access so your licensed plumbers do what they're licensed to do, in a trench that's actually workable.
Most plumbing companies don't want to hand-tunnel under a slab, and they shouldn't have to. It's slow, it's hard on a crew, and every hour a journeyman spends on a shovel is an hour they're not billing pipe work. We're the dig partner: you keep the customer and the licensed repair; we open and close the ground. Because we come out of foundation repair, we already know how the line runs under a Central Texas slab and how much room you need to make a joint.
When you call us
The jobs that need a tunnel.
Broken or collapsed sewer line
A cast-iron or PVC sewer line fails under the slab and the camera says it's mid-run, not at the cleanout. We tunnel in from the exterior to the break so you replace pipe instead of chasing it through the house.
Cast-iron replacement
Sixty-year-old cast iron is scaling shut house-wide. We open a tunnel along the main run so you re-pipe in continuous lengths with room to slope it correctly — not in jackhammered pits room by room.
Slab leak on the supply side
A hot- or cold-line leak under the slab needs a reroute or a spot repair. We dig the access so the line is exposed and dry before you cut in.
Belly or back-pitch in the drain
A hydrostatic test or camera shows standing water in a low spot. We tunnel the affected run so you can re-lay it to grade.
No interior demolition wanted
The homeowner can't lose tile, hardwood, or a remodeled bath. Tunneling from outside keeps the floor intact — a strong selling point you can offer on the bid.
What you get
How we work with you.
Here's what a plumber-dug-by-amateurs tunnel costs you: a bore too narrow to work in, no slope to the floor so it pools, spoil in the way, and no shoring — so your crew is uneasy the whole time. We dig the tunnel to the size your repair needs, widen it at the fitting, keep it shored and dry, and stage the spoil clear. You show up to an open, ready trench, do the pipe work, and call us back to backfill and compact in lifts so the ground settles right. We protect the relationship, too — it's your customer and your licensed repair; we never touch the pipe.
SCOPE OF WORK
- Exterior or interior tunnel dug to your pipe run, depth, and pitch
- Work area widened and shored where the repair happens
- Spoil staged clear; trench kept dry and lit
- Documented hand-off, then backfill and compaction in lifts after your repair
- Texas 811 locates called before the dig
How every bore is held
Velocity, precision, OSHA, quality control — and the standards behind them.
Tunneling is the slow, risky part of a plumbing or foundation job. We run it like a discipline, not a dig.
Velocity
Hand-tunneling is the slow part of a plumbing or foundation job. We staff the bore to the schedule, dig in clean shifts, and hand the plumber an open, ready trench so their billable hours aren't spent waiting on a shovel.
Precision
We dig to the plan — depth, width, and pitch shot before the first spade, then verified as we go. The pipe run, the pier location, or the engineer's access point lands where the drawing says it should, the first time.
OSHA safety
Tunneling and trenching carry real cave-in exposure. We work to OSHA Subpart P excavation practice — protective systems, safe access and egress, spoil set back from the edge, water and air managed, and daily competent-person inspection.
Quality control
Every bore is checked against the drawing: width to work in, clean floor and walls, true pitch, and a documented hand-off. Backfill is placed and compacted in lifts so the ground — and anything on it — settles right.
Standards & compliance
Texas 811 is called and lines are located before we dig. We sell the access, not the licensed pipe work — your plumber stays the plumber. Permits, locates, and clean documentation come standard.
Why a foundation crew digs a better tunnel
We come out of foundation repair, and we've dug alongside plumbers for years — so we know how to dig it.
We know how a sewer line under a slab actually runs, where the belly usually hides, and how much room a plumber needs to set a fitting, swing a saw, and lie comfortably to make a joint. We open the work area wider where the repair is, shore it, keep it dry, and light it — then get out of the way. The plumber shows up to a tunnel they can work in, not a hole they have to fight. That's the difference between a bore dug by people who've only moved dirt and one dug by a foundation crew who has watched the pipe work happen a hundred times.
- We open the work area wider where the repair is — room to set, slope, and joint
- Shored, dry, and lit so the plumber works in a tunnel, not a hole
- We dig it and back-fill it; your licensed plumber does the pipe work
From locate to backfill
How an under-slab tunnel runs.
Locate & plan
We call Texas 811, locate utilities, and shoot the depth, width, and pitch the repair needs before a spade hits the ground.
Open the entry
A compact entry pit goes in at the chosen point — usually outside the foundation — so the floors above stay whole.
Tunnel to the work
We hand-tunnel to the pipe run, pier location, or access point, widening the bore where the repair happens.
Shore & hand off
The bore is shored and inspected, then handed to your licensed plumber, foundation crew, or engineer — open, dry, and workable.
Backfill in lifts
Once the repair passes, we place backfill in compacted lifts so the slab, drive, or walk above settles correctly.
Clean & document
Spoil hauled, site restored, and the access and backfill documented for your file or warranty.
LICENSING & SAFE DIGGING
In Texas, plumbing repairs are regulated by the Texas State Board of Plumbing Examiners — Tradesman, Journeyman, Master, and Inspector licenses. Motmot sells under-slab tunneling and access excavation; we partner with your licensed plumber for the pipe repair itself. And before any dig, Texas 811 is contacted at least two business days ahead so gas, water, and utility lines are located first.
Industry FAQ
Plumbing companies tunneling — questions answered.
From real jobs
What this access looks like on real jobs.
Tunneling for other industries
Foundation repair
Foundation repair tunneling.
See foundation repair tunneling →Structural engineers
Engineer-access excavation for under-slab evaluations.
See structural engineers tunneling →GCs & remodelers
Under-slab access for remodel plumbing.
See gcs & remodelers tunneling →Property mgmt & multifamily
Low-disruption under-slab tunnel access for rental and multifamily properties.
See property mgmt & multifamily tunneling →Investors & flippers
Pre-sale and investor property tunneling for plumbing/foundation access.
See investors & flippers tunneling →Realtors & inspectors
Under-slab access for repair work before closing.
See realtors & inspectors tunneling →Restoration & insurance
Access excavation for slab leak and water-damage repairs.
See restoration & insurance tunneling →Commercial facilities
Commercial under-slab tunneling for plumbing and structural access.
See commercial facilities tunneling →Backfill & cleanup
Tunnel backfill and cleanup.
See backfill & cleanup tunneling →Need under-slab access? Tell us the run.
We'll scope the tunnel, dig it to plan, shore it, and back-fill it clean — so your licensed repair goes in smoothly and the floors above stay whole.
Now booking free inspections in Central Texas.