When Underground Sewer Repair Requires Excavation
Excavation is the correct approach when the pipe failure type or condition falls outside what trenchless methods can address. These are the specific conditions that require direct access to the pipe.
Pipe Belly and Grade Failure
A belly is a section of pipe that has lost its downward slope and sags below the correct grade. Wastewater collects in the low point instead of flowing toward the main. Solids accumulate at the belly and create persistent backups that return regardless of how frequently the line is cleaned.
Trenchless methods cannot correct a belly. CIPP lining follows the existing pipe contour and will line the belly in place, creating a smooth-walled belly rather than eliminating it. Pipe bursting follows the existing pipe path and installs a new pipe in the same sagging position. Belly correction requires excavating to the low point, removing and re-grading the pipe section, installing new pipe at the correct slope, and restoring the surface. There is no workaround.
In Denver’s expansive clay soil, bellies form when soil beneath the pipe settles or contracts during dry conditions. The Front Range experiences significant seasonal moisture variation, and clay soil movement follows it. Properties built over moisture-sensitive soils, poorly compacted fill, or areas that have experienced settlement may develop sewer grade problems over time. Camera footage and prior inspection records can help determine whether a belly is isolated or part of a recurring condition along the line.
Fully Collapsed Pipe Sections
A collapsed section has no remaining pipe wall for a liner to bond to and no continuous pipe path for a bursting cable to pass through. Pipe bursting requires a passable path. CIPP lining requires a structurally present host pipe. Both conditions are absent when a section has fully collapsed.
Excavation to a collapsed section removes the failed pipe material, establishes the correct grade and depth for the replacement section, installs new pipe, and reconnects it to the surrounding pipe on both sides. Where the collapse is isolated to a short section with sound pipe on either side, spot excavation addresses only the failed section.
Sewer Line Belly Repair: What the Process Involves
Belly repair is the most common excavation-required condition we encounter on Denver and Aurora commercial and residential properties. The process is more involved than a standard pipe section repair because it requires grade correction, not just pipe replacement.
Camera Scope and Belly Location
The camera scope locates the belly precisely within the pipe run. We identify the low point, measure its depth relative to the surrounding pipe grade, and assess the length of the affected section. This determines the excavation footprint required to access the belly and re-establish grade on both sides.
The camera footage also shows whether the belly is isolated or part of a pattern across the run. A single belly in otherwise sound pipe is a spot excavation. Multiple bellies distributed across the lateral, or a long section with insufficient grade throughout, may indicate a more extensive scope.
Underground Sewer Repair on Commercial Properties: What Differs
Commercial underground sewer repair involves different planning, permitting, and coordination requirements than residential repair. These are the factors that change the project approach on a commercial property.
| Commercial Factor | What It Means for the Excavation Project |
| Parking lot and driveway surfaces | Asphalt and concrete over the repair zone require cutting and restoration. Surface restoration cost is planned and priced before work begins, not added after the fact. |
| Underground utility density | Commercial properties have denser utility corridors than residential. We locate all utilities before excavation and assess conflicts before the dig plan is finalized. |
| Larger pipe diameters | Commercial mains run at 4 to 8 inches or larger. Larger diameter requires more excavation width, heavier pipe material, and different bedding and backfill specifications. |
| Permitting requirements | Commercial excavation in Denver and Aurora typically requires city permits and an inspection before the trench is closed. We handle permit applications and inspector scheduling. |
| Occupied site coordination | Excavation at occupied commercial properties requires planning around tenant access, parking availability, and business operations. We coordinate with property management before the dig starts. |
| Shoring requirements | Excavations deeper than 5 feet in unstable soil require shoring per OSHA standards. We assess shoring requirements based on depth and soil conditions before beginning any excavation. |
| Documentation requirements | HOA boards and property managers need written scope documentation, permit records, camera footage, and inspection sign-offs. We produce all of this as standard practice on every commercial underground repair. |
Underground Sewer Conditions in Denver and Aurora That Drive Excavation Work
Clay Soil Settlement and Pipe Grade Loss
Clay-rich or moisture-sensitive soils can expand and contract as moisture conditions change. Sewer grade can also be affected by poorly compacted backfill, localized settlement, erosion, or changes in support beneath the pipe. The effect varies by property and cannot be determined from the building’s age or neighborhood alone. Camera inspection and site evaluation are used to identify whether settlement has contributed to a belly, offset joint, or loss of grade.
Deep Frost Line and Winter Heave Effects
Sewer joints and grade can shift when soil support beneath or around the pipe changes. Contributing conditions may include localized settlement, erosion, poor bedding, moisture-related soil movement, or earlier excavation near the line. Camera inspection identifies the resulting belly or offset, while excavation reveals the support conditions that must be corrected before new pipe is installed.
Aurora’s 1970s Multi-Family Infrastructure
Shared sewer mains on Aurora apartment and multi-unit properties can be affected by settlement, inadequate pipe support, joint movement, or loss of grade. Because one main may serve multiple units, a belly or collapsed section can disrupt several occupants at once. We use camera inspection and surface locating to identify the affected section before determining whether targeted excavation or a broader replacement scope is required.
Old Clay Tile and Orangeburg in Pre-1960 Properties
Older Denver properties may contain clay, Orangeburg, cast iron, or previously replaced sewer sections within the same lateral. Clay lines may develop cracked or separated joints, while Orangeburg can flatten, deform, or lose structural integrity as it deteriorates. Camera inspection confirms the actual material and whether the line has a combination of grade loss, joint displacement, root intrusion, or structural failure. When grade and pipe structure both need correction, excavation may address those conditions within one repair scope.
Our Underground Sewer Repair Process
Step 1: Camera Scope and Failure Assessment
Every excavation job begins with a full camera scope. The footage locates the failure precisely within the lateral, identifies the type and severity of each failure, documents surrounding pipe condition, and establishes whether the failure is isolated or part of a broader pattern. Camera footage also shows any secondary conditions, such as additional bellies or offset joints, that may affect the excavation scope.
Step 2: Trenchless Assessment and Written Options
Before recommending excavation, we assess whether any trenchless method is viable for the specific failure conditions shown on camera. When trenchless is a viable option, we present it alongside the excavation option with pricing for both. When it is not viable, we explain specifically why and proceed to the excavation plan. No excavation is recommended before the trenchless assessment is complete.
Step 3: Utility Location and Excavation Planning
Before any digging starts, we call 811 to locate underground utilities and conduct our own field verification in the repair zone. On commercial properties, we assess surface conflicts, shoring requirements based on depth and soil conditions, and the excavation footprint that balances repair access with minimizing surface disruption. The excavation plan is confirmed with the property manager or owner before equipment moves in.
Why Properties Choose Sewer Lines Only for Underground Sewer Repair
- Camera scope before every excavation recommendation. We do not recommend digging without camera footage that shows specifically why trenchless methods are not viable for the failure condition found.
- Trenchless assessment before any excavation plan. If trenchless is viable, we present it first with pricing. Excavation is recommended when camera evidence shows it is the correct approach, not as the default.
- Our own excavation crews, no subcontracting. Our excavation teams and plumbers work under one company. There is no subcontractor relay between the dig crew and the pipe crew, which means one accountable team from first camera scope to final surface restoration.
- Precise excavation to the failure point. Minimum footprint excavation reduces surface restoration cost and project timeline without reducing repair quality.
- Commercial permitting handled in-house. Permit applications, city inspections, and shoring assessments are part of every commercial underground repair scope.
- Post-repair camera verification and documentation. The complimentary post-repair camera video and written service report are provided to the property upon completion of the repair.
- 5-year transferable warranty on all underground sewer repairs. Transfers with the property.
- 927 Google reviews with a 4.9-star rating from property managers, HOA boards, contractors, and residential clients.
- Free estimates and free second opinions. If you have been told your property needs excavation and want a second opinion on whether trenchless is viable, we scope the line and provide a written assessment at no charge.
Frequently Asked Questions
Schedule an Underground Sewer Evaluation in Denver or Aurora
Sewer Lines Only scopes the line, assesses trenchless viability, presents written repair options with pricing, and completes excavation-based repairs with our own crews and equipment from camera scope through surface restoration.
Call 303-562-9800 for a free underground sewer evaluation or to schedule a camera scope. Free second opinions on excavation recommendations are available. If you have been told trenchless is not an option and want verification, we will scope the line and provide a written assessment at no charge.
Use the contact form on this page for written inquiries. We respond to all underground sewer requests within one business day.
