Comply with General Laws · 3 min read
Requirements for Temporary Underground Facility Markers
The One-Call System
Before excavation, contractors must notify underground facility operators. The one-call system (also called "Call Before You Dig" or "811") coordinates this notification process nationally.
Purpose
Prevent damage to underground utilities
Protect worker safety
Avoid service interruptions
Reduce liability exposure
Legal Mandate
All 50 states have damage prevention laws
Federal Pipeline Safety Improvement Act supports state programs
One-call notification is legally required before excavation
Notification Requirements
Timing Requirements
Minimum advance notice varies by state (typically 48–72 hours, excluding weekends and holidays)
Maximum ticket validity period (typically 10–30 working days)
Renewal required for extended projects
Information Required
Excavator name and contact information
Excavation location (address, intersection, GPS coordinates)
Type of work to be performed
Extent of excavation area
Start date and time
Depth of excavation
Exemptions
Emergency excavations (but notification required as soon as practicable)
Excavations on private property in some states (varies by jurisdiction)
Agricultural operations in some states (limited exemptions)
Routine road maintenance at shallow depths (varies)
Facility Operator Responsibilities
Upon notification, facility operators must:
Respond within required timeframe
Mark facility locations with surface markers
Provide facility information to excavator
Clear the excavation area if no facilities present
APWA Uniform Color Code
The American Public Works Association established standardized marking colors:
| Color | Facility Type |
|---|---|
| Red | Electric power lines, cables, conduit, lighting cables |
| Yellow | Gas, oil, steam, petroleum, gaseous materials |
| Orange | Communication, alarm, signal lines, cables, conduit |
| Blue | Potable water |
| Purple | Reclaimed water, irrigation, slurry lines |
| Green | Sewer and drain lines |
| Pink | Temporary survey markings |
| White | Proposed excavation area |
Exam Alert: Memorize this color code. Questions commonly test association between colors and facility types.
Marking Methods
Acceptable temporary marking methods include:
Surface Markers
Paint (water-based for environmental compliance)
Flags on wire stems
Stakes with color coding
Whiskers (short flexible markers)
Marking Placement
Directly over facility centerline
At regular intervals along facility path
At changes in direction
At facility terminations
Offset markings when surface directly above facility is unavailable
Marking Information
Facility owner identification (abbreviation or logo)
Facility type
Direction of facility run
Depth (when known and when regulations require)
Tolerance Zone
The tolerance zone is the area surrounding marked facilities where hand digging or alternative excavation methods are required:
Typically 18–24 inches on each side of marked facility
Some jurisdictions specify 24 inches or greater
Mechanical excavation prohibited within tolerance zone
Vacuum excavation often permitted within tolerance zone
Excavator Responsibilities
After facilities are marked, excavators must:
Before Digging
Verify all utilities have responded
Understand marking locations
Plan excavation approach
Use white markings to delineate work area
During Excavation
Maintain visual markers throughout project
Hand dig within tolerance zone
Support exposed utilities
Protect facilities from damage
Damage Reporting
Immediately report any facility damage
Do not backfill damaged facilities
Evacuate area for gas leaks
Call 911 for emergencies
Penalties for Non-Compliance
Failure to comply with one-call requirements results in:
Fines (typically $1,000–$100,000 depending on jurisdiction and severity)
Liability for repair costs
Liability for service interruption damages
Criminal charges for willful violations
License suspension or revocation
Increased insurance premiums
Emergency Excavation
When emergency excavation is necessary:
Begin notification process immediately
Document emergency circumstances
Take reasonable precautions to protect facilities
Complete notification as soon as practicable
Emergency does not eliminate liability for damages
Preservation of Markings
Excavators must preserve facility markings:
Maintain marks throughout project duration
Re-mark or reference marks before destruction
Request re-marking if marks become obscured
Document original mark locations
Private Utilities
One-call systems typically do not locate:
Private utilities beyond service connection
On-site septic systems
Private wells
Irrigation systems on private property
Interior building utilities
Excavators are responsible for locating private utilities through other means (private locating services, as-built drawings, property owner information).
Examination Focus Points
Key concepts for the exam:
811 is the national one-call number
Notification timing requirements (48–72 hours typical)
APWA color codes must be memorized
Tolerance zone dimensions (18–24 inches typical)
Hand digging required within tolerance zone
Excavator liable for damages to unmarked facilities if notification not made
Emergency excavation still requires notification as soon as practicable
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