Subsurface Utility Engineering
Subsurface Utility Engineering Services for Civil Design Teams
Engineering-grade utility locating aligned with ASCE 38-22 quality levels. We help civil engineers verify what is actually underground so utility conflicts are addressed in design, not during construction.
Sound Familiar?
You're designing around utility data you know is incomplete.
The drawings show structures, but no confirmed line routing between them.
811 marks stop at the meter while your project extends far beyond that point.
A contractor has already hit something that was never shown on plans.
You need engineering-grade utility data, not just paint marks that fade in a week.
You should not have to wait until excavation starts to learn that utility data was wrong. Subsurface utility engineering solves this problem before construction begins.
What Is Subsurface Utility Engineering?
Subsurface utility engineering (SUE) is a systematic approach to managing risks from underground utilities during civil infrastructure design and construction. Unlike basic utility locating, SUE services follow the ASCE 38-22 standard (formerly ASCE 38-02) to investigate, classify, and document utilities at defined quality levels—giving engineers the confidence to make design decisions based on verified data rather than assumptions.
Our subsurface utility engineering services combine GPR, electromagnetic locating, and survey-grade GPS to detect private utilities, abandoned lines, and unmapped infrastructure that create design-phase conflicts. We deliver engineering-grade utility maps, SUE CAD drawings, and utility conflict identification reports that integrate directly into your Civil 3D workflow.
Why is SUE important? Because incomplete utility data during design leads to costly surprises during construction. Utility conflicts discovered after plans are stamped result in change orders, schedule delays, and safety incidents. Subsurface utility engineering for design prevents these outcomes by providing verified, classified utility data when it matters most—before construction mobilization.
ASCE 38-22 SUE Quality Levels
The ASCE 38 standard defines four quality levels for subsurface utility engineering, each providing increasing confidence in utility data.
Quality Level D
Existing Records Review
We collect and reconcile existing utility records from municipalities, utility operators, and previous project files. Quality Level D SUE establishes a baseline utility map from available documentation before any field work begins.
Deliverables:
- • Record compilation report
- • Utility atlas from existing data
- • Identified information gaps
Quality Level C
Surface Feature Survey
Field survey of visible surface features including manholes, valve boxes, hydrants, pedestals, and other utility indicators. Quality Level C correlates surface evidence with record data to improve routing confidence.
Deliverables:
- • Surface feature survey data
- • Correlated utility map
- • Updated utility atlas
Quality Level B
Designating (Non-Destructive Locating)
Active subsurface investigation using GPR, electromagnetic locating, and signal tracing to map utility alignments and estimate depths without excavation. Quality Level B SUE—also called a designator survey—provides the engineering-grade utility detection data that civil design teams need for conflict analysis.
Deliverables:
- • Designated utility linework with coordinates
- • Depth estimates at conflict points
- • CAD/GIS-compatible files
Quality Level A
Test Hole Utility Verification
Physical exposure of utilities at critical conflict points through vacuum excavation (potholing) to verify exact horizontal position, depth, material, size, and condition. QL-A utility engineering provides the highest confidence data for final design decisions.
Deliverables:
- • Verified utility coordinates and depths
- • Material and condition documentation
- • Photographic evidence
Our SUE Process
1
Project Scoping
We review your schedule, site conditions, current utility information, and design requirements to define the appropriate SUE quality level and survey scope.
2
Records Research (QL-D)
We compile existing utility records, as-built drawings, and municipal databases to establish baseline subsurface information before mobilizing to the field.
3
Field Designation (QL-B)
Our technicians combine GPR, EM locating, and RTK GPS to map utility alignments, verify critical depths, and produce engineering-grade utility location data.
4
Engineering Deliverables
You receive attributed utility linework with coordinates, depth data, a utility conflict matrix, and clear documentation of findings and limitations—all in CAD-ready formats.
No paint marks that fade in a week. No guesswork. Engineering-grade SUE deliverables you can design around with confidence.
SUE Deliverables
Survey-grade GPS coordinates for detected utility alignments
Depth measurements at critical utility conflict points
CAD/GIS-compatible files (DWG, shapefile, or project-required format)
Utility conflict matrix identifying design-phase risks
SUE technical reports with documented findings and limitations
Data that integrates directly into Civil 3D workflows
Engineering-grade utility maps suitable for ASCE 38-22 compliance
Optional add-on: Quality Level A test hole utility verification through vacuum excavation at critical conflict points.
Why Choose Our SUE Services
ASCE 38-22 ALIGNED WORKFLOW
Our subsurface utility engineering process follows the ASCE 38-22 standard (the updated ASCE 38-02), ensuring utility investigations meet recognized industry quality level requirements from QL-D through QL-A.
MULTI-TECHNOLOGY DETECTION
We combine GPR for non-metallic infrastructure and EM locating for metallic lines. This engineering-grade utility locating approach reduces missed utilities compared to single-method surveys.
SURVEY-GRADE POSITIONING
RTK GPS captures utility coordinates with high precision, replacing paint-only markouts with professional utility mapping data that supports design-phase utility conflict detection.
DESIGN-PHASE TIMING
SUE field work and deliverables are scheduled during design so routing decisions can account for subsurface conflicts before they become expensive construction change orders.
ENGINEERING-READY DELIVERABLES
We deliver SUE CAD drawings, engineering-grade utility maps, and attributed digital files your team can use directly—not field sketches that need transcription.
UTILITY CONFLICT IDENTIFICATION
Beyond locating, we document utility conflicts relative to proposed alignments so your team can evaluate risk and plan mitigations during design rather than during construction.
✓ Professional liability (E&O) coverage
✓ ASCE 38-22 compliant SUE investigation workflow
✓ Serving Northern Indiana and the surrounding Midwest
Who Needs Subsurface Utility Engineering?
SUE for civil engineers, DOT projects, municipal infrastructure, and any design involving subsurface conflicts.
Road widening and highway design projects
New construction near existing utilities
Utility relocation and coordination projects
Municipal infrastructure improvements
SUE for engineering firms managing design liability
Pre-construction utility conflict detection
Frequently Asked Questions About SUE
What is subsurface utility engineering?
Subsurface utility engineering (SUE) is a branch of civil engineering that manages risks associated with underground utilities during design and construction. SUE uses a systematic process defined by ASCE 38-22 (formerly ASCE 38-02) to investigate, classify, and document subsurface utilities at defined quality levels—from records research (QL-D) through physical verification (QL-A). The goal is to provide engineering-grade utility data that reduces design conflicts, construction delays, and utility strikes.
What are the SUE quality levels?
The ASCE 38-22 standard defines four SUE quality levels. Quality Level D involves collecting existing utility records. Quality Level C adds surface feature surveys to correlate with records. Quality Level B uses non-destructive methods like GPR and electromagnetic locating to designate utility alignments and depths—this is often called a designator survey. Quality Level A involves physical test hole utility verification through vacuum excavation to confirm exact position, depth, material, and condition.
What is the difference between SUE quality levels?
The difference between SUE quality levels is the confidence and precision of the utility data. QL-D relies solely on existing records. QL-C adds field observation of surface features. QL-B adds non-destructive subsurface investigation using GPR and EM technology to designate utilities. QL-A provides the highest confidence through physical exposure and measurement at specific conflict points. Most civil design projects require at least Quality Level B data, with QL-A at critical crossings.
What is the ASCE 38 standard?
ASCE 38 is the industry standard for subsurface utility engineering published by the American Society of Civil Engineers. The original ASCE 38-02 was updated to ASCE 38-22, which defines quality levels, investigation procedures, and documentation requirements for utility investigations supporting civil infrastructure design. Many DOT agencies, municipalities, and engineering firms require ASCE 38-compliant SUE on public infrastructure projects.
How is SUE different from utility locating?
Standard utility locating identifies where utilities are and marks them on the surface. Subsurface utility engineering goes further by classifying data quality, documenting utility attributes, producing engineering-grade deliverables (CAD drawings, conflict matrices, technical reports), and integrating findings into the civil design process. SUE is an engineering discipline; utility locating is a field service. SUE for civil engineers provides the rigor and documentation that design-phase decisions require.
When do I need subsurface utility engineering?
You need subsurface utility engineering when designing infrastructure near existing utilities—road widening, new construction, utility relocations, or any project where utility conflicts could impact design decisions, construction costs, or safety. SUE is especially valuable during the design phase when utility conflict detection can prevent expensive change orders. Many DOT and municipal projects now require ASCE 38-compliant SUE as part of the design process.
How is this different from 811 utility marking?
811 coordinates public utility markouts, which often stop at ownership boundaries and provide paint marks without depth data or engineering documentation. Subsurface utility engineering services target both public and private infrastructure, include depth verification, produce SUE CAD drawings and technical reports, and align with ASCE 38-22 quality level standards. SUE delivers engineering-grade utility maps that civil design teams can rely on—not temporary paint marks.
Does INDOT require SUE on all highway projects?
INDOT (Indiana Department of Transportation) increasingly requires or strongly recommends ASCE 38-compliant SUE investigations on highway design projects, particularly for road widenings, intersection improvements, and new alignment projects where utility conflicts are likely. While INDOT requirements vary by project type and funding source, federally-funded projects (FHWA) commonly require SUE as part of the design process. INDOT's Design Manual references utility coordination procedures aligned with ASCE 38 quality level concepts. Engineering firms managing INDOT design contracts should review project-specific requirements with their INDOT project manager early in the design phase. Our team is experienced with Indiana DOT project documentation requirements and can provide ASCE 38-22 compliant deliverables that satisfy INDOT's utility coordination requirements.
What is the difference between QL-B and QL-A for a highway project?
For highway projects, Quality Level B (QL-B) and Quality Level A (QL-A) serve distinct purposes and are typically used together rather than as alternatives. QL-B designation uses non-destructive methods—GPR, electromagnetic locating, and RTK GPS—to map utility alignments and estimate depths across the entire project corridor. QL-B data supports route selection, design conflict analysis, and utility relocation coordination. Quality Level A goes further at specific critical conflict points by physically exposing utilities through vacuum excavation (potholing) to verify exact horizontal position, vertical depth, material, size, and condition. For highway projects, the typical approach is QL-B across the full corridor to identify conflicts, followed by QL-A test holes at the 5–10 most critical crossings where design decisions depend on verified utility data. This combination provides comprehensive coverage while concentrating physical verification resources where they matter most.
Get Subsurface Utility Engineering Before Design Decisions Are Locked In
15 minutes. No hard pitch. Just a project conversation about your current utility data, SUE quality level needs, and next steps.
No obligation • Fast response • Indiana and surrounding Midwest