Steps to plan underground infrastructure projects

Identify all underground utilities on your site

The first step in any underground infrastructure project is knowing exactly what's beneath the ground. Before you can plan safely and legally, you need a complete picture of where public and private utilities run—water lines, gas pipes, electrical conduits, telecommunications cables, storm drains, and sanitary sewers. Many projects fail because contractors assume they know what's there, only to hit a utility and cause expensive damage, service outages, and potential injuries.

Start by contacting your local one-call utility notification center, which is a free service in most regions. They'll notify utility operators on your behalf, and those companies will send their field representatives to mark lines on your property. This is not optional—it's required by law before any excavation. Different utilities use different colored paint or flags, so make sure your team understands the standard color codes. Some utilities may not be marked by one-call—private lines serving single buildings, for example—so you'll need to investigate those separately with property owners.

Why marking isn't enough

One-call marking is essential but incomplete. The marks show where utilities are at ground level on the day of the visit, but underground lines run at different depths, and the marked line might not account for their actual position. Some utilities are also difficult to locate accurately with standard marking methods. Professional utility locating is often necessary, especially for complex sites or when marking results are unclear.

Conduct professional site assessments

After one-call notification, engage utility locating and site assessment professionals to get a detailed picture of what's underground. Professional locators use specialized equipment including ground-penetrating radar (GPR), electromagnetic locating, and other detection methods to find utilities more precisely than visual marking alone. A thorough site assessment identifies not just the location of utilities but their depth, type, and condition—information critical for safe project planning.

During the assessment, the professional team marks utilities in three dimensions: horizontal position, depth below ground, and type of utility. They'll also note any hazards specific to your site, such as unstable ground, areas where utilities cluster, or locations where previous damage occurred. This creates the foundation for all your planning decisions. The assessment should also document any private utilities that won't appear on standard utility maps, such as drainage systems or gas lines serving specific buildings.

Map and document all assets

Raw location data needs to be converted into a usable map and documentation system that your team can reference throughout the project. This is where GIS and CAD documentation come in—professional mapping that shows utility locations on a scale drawing of your property. A good map shows each utility's type, location, depth, and any known issues or hazards. This becomes your single source of truth during design and construction, and it serves as a legal record of what was known before work began.

Digital mapping also allows you to share information easily with architects, engineers, contractors, and subcontractors, ensuring everyone on the project works from the same information. Changes and discoveries during construction can be added to the map, creating a record of what was actually found versus what was predicted. Many projects benefit from keeping this map on-site and updating it as work progresses.

Plan your project layout around utilities

With a complete understanding of where utilities are located, your design team can now plan the project to avoid or protect those utilities. This is where civil engineering and structural engineering principles guide your approach. The goal is to design your project so that critical utilities remain undisturbed, or if disturbance is unavoidable, it happens under controlled conditions with proper notification and support.

Consider these planning principles:

• Avoid utility corridors when possible—place buildings, roads, or structures in areas free of utilities
• Maintain minimum clearances from utilities according to relevant codes and standards
• Plan excavation sequences to address utilities in a logical order, starting with the most critical or highest-risk lines
• Design utility protection systems if conflicts cannot be avoided, such as boring under pipelines or building utility tunnels
• Identify points where your project will cross utilities and plan those crossings in detail before construction

This planning phase often reveals that the initial project design isn't feasible, requiring revisions. It's far better to discover this during design than during construction, when changes become exponentially more expensive.

Implement damage prevention programs

Even with careful planning, damage prevention during construction is essential. Develop a damage prevention program specific to your project that outlines how your team will protect utilities during work. This includes establishing exclusion zones where no digging occurs without locating first, assigning utility spotters on site during excavation, and ensuring all personnel understand the locations and types of utilities near their work areas.

A good damage prevention program also includes communication protocols. If any digging is planned that wasn't anticipated during the planning phase, someone needs to notify the utility companies before work begins. Some utilities require a representative on-site during excavation; your program should account for these requirements and schedule their presence in advance.

Use professional verification during construction

As construction proceeds, keep professional utility locating services available for verification and investigation. Even with thorough planning, conditions on the ground sometimes differ from predictions. Hand digging to verify utility locations before powered equipment is used can prevent disaster. If you encounter a utility that wasn't marked or documented during planning, have it professionally verified and located before proceeding.

Some projects also require verification that utilities that were supposed to be protected actually remained undisturbed. This inspection protects both the utility owner and your organization by creating a record of what happened during construction. If damage does occur, professional verification documents what was done to prevent it.

Prepare documentation for compliance

Throughout your project, maintain thorough documentation of all locating efforts, utility markings, site assessments, design decisions, and construction activities involving utilities. This documentation serves several purposes: it proves you followed proper procedures if anyone questions your compliance with regulations, it provides a record for future projects on the same site, and it can prevent disputes if utility damage occurs.

Call Underground Infrastructure Intelligence at (317) 350-4623 to discuss your specific project. Their team handles utility locating, site assessments, damage prevention programs, and mapping and GIS documentation—the complete range of services needed to plan underground infrastructure projects safely and properly. They're open 7 days a week, 7am–7pm, ready to help with your project needs.