Vacuum Excavation & Test Hole Services

We Know Utility Data

End the Guess Work for Underground Utility Data


Trinity Subsurface, LLC uses the process of vacuum excavation, also known as potholing or daylighting, to safely obtain critical subsurface utility data such as:

  1. Utility Depth / Elevation
  2. Precise Horizontal Location
  3. Precise Utility Size & Material Composition
  4. Utility Condition
  5. Subsurface Conditions & Back-fill Composition
The use of vacuum excavation is the safest excavation method to obtain Quality Level A utility data in accordance with CI/ASCE 38-02. Vacuum excavation works by excavating a small test hole approximately 15 inches in diameter over the crown or corner of an underground utility. Spoils are disturbed using pressurized air or water, and are extracted from the test hole using a high powered vacuum.
  1. As the client, you would provide test hole locations or consult with Trinity Subsurface field employees to determine utility conflicts that require Quality Level A subsurface utility data.
  2. The location of the utility is verified using surface geophysical equipment prior to breaking ground.
  3. A small 15″ diameter hole is excavated over the utility. Once exposed, utility data is collected.
  4. The hole is backfilled using the spoils that were removed from the hole and the crown, center, or corner location of the utility is marked on the surface using a wooden stake or Mag-Nail®.
  5. A test hole data sheet is generated documenting all of the underground utility data collected for the test hole location. 

Vacuum excavation has the capacity to collect all kinds of critical utility data for various construction and engineering activities. Utility data is important to eliminate conflicts with underground utilities when installing new utilities or structures, and when existing utilities need to be connected to. 

Trinity Subsurface Engineering works with clients to collect the data that is most important to them, and the standard data we collect includes:

  • Depth / Elevation of Utility
  • Outside Diameter / Width of Utility
  • Precise Horizontal Location
  • Material Composition
  • General Utility Condition
  • Surface Material (Grass / Asphalt / Etc)
  • Back-fill Material
  • Location of Test Hole (Swing Ties)
  • General Notes & Unusual Circumstances Encountered

Underground utility data that is collected in a test hole using air vacuum excavation is documented on a Test Hole Data Sheet. This is a report that is completed in the field. Test hole locations are serialized and organized using a project number sequence. 

Each test hole we excavate is documented with a data sheet, even if no utility is discovered. If additional utilities are discovered in a test hole location, additional test hole data sheets are completed for those utilities. 

Utility locations and utility data may also be surveyed and added to existing civil drawings, or they can be sketched out using a satellite image. We also include a test hole matrix, which charts out a snapshot of the data for each test hole performed on one easy to read report.

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With decades of experience the engineers and technicians at Trinity have the industry insight to provide quality utility locating services. We understand the needs of engineers, contractors, construction managers and owners.