What does an 811 locate tell you?
Missouri 811 coordinates notification to member utilities for planned digging. The utility owners or their locators respond to the request. Surface marks help identify where covered facilities are expected within the described work area.
Those marks are not a depth survey. Missouri 811 explains that it does not provide utility depth information. A line’s actual depth may differ along its route, so a mark on the lawn does not establish how far below a proposed trench or footing the utility lies.
Follow the current Missouri 811 excavator process for the ticket, required waiting period, utility responses, and any missing or unclear marks. Scheduling a hydrovac does not replace that process. The excavation area described on the ticket also needs to match the work that will actually take place.
Which lines may need a private locator?
Do not assume an 811 request marks every buried line on a property. Missouri 811’s public and private utility guidance explains that privately owned facilities can require a private locating company. Examples include an owner’s underground feed to a detached garage or pool.
Bring up private facilities during planning, even if old drawings are incomplete. Tell the contractor about outbuildings, irrigation, site lighting, past additions, and lines installed after the original building. Records and visible equipment provide leads for investigation; they do not establish a clear excavation path by themselves.
Clarify who is arranging private locating and what information the excavation crew will receive. “Utilities marked” is too vague if one person means member utility marks and another assumes the private site network has also been investigated.
What does utility potholing add?
Potholing, also called utility daylighting, creates a controlled opening to expose a selected part of a buried facility. A hydrovac uses water to loosen soil and a vacuum to remove the resulting spoil. The work should be planned and performed with methods appropriate to the facility and conditions.
The exposure lets the project team verify the utility at that location and obtain the measurements needed for the design or construction decision. A crossing under a planned sewer trench, for example, may need a known elevation before the trench route is finalized. The measurements and their reference point should be agreed on before the crew starts.
An exposure confirms a point, not every foot of the line. Utilities can change direction or elevation between test holes. If the project needs multiple crossings verified, identify each one in the scope.
| Step | Information it provides | What it does not establish |
|---|---|---|
| 811 notification and member locates | Responses and estimated routes for covered facilities | Every private line or a verified excavation depth |
| Private locating | Investigation of the owner’s private facilities within the agreed scope | Guaranteed detection of every unknown line |
| Potholing | Direct exposure and verification at selected points | A continuous survey of the whole route |
| Survey and documentation | Recorded positions or elevations to the required reference | Permission to disregard site conditions during excavation |
When should verification happen?
Do it early enough to change the plan. For a proposed utility crossing, that means before committing the trench crew or boring equipment to a route that depends on an assumed clearance. For an addition, it may mean before finalizing the footing arrangement near an existing service.
OSHA’s excavation requirements call for determining the exact location of underground installations by safe, acceptable means as excavation approaches their estimated position. The rule does not make a painted route a substitute for verification.
If you are planning utility trenching, ask the contractor where physical exposures are needed and how they fit into the installation sequence. Also agree on protection of the openings, documentation, backfill, and surface restoration.
How to scope potholing with J1S
Send the site address, marked-up plan, number of exposure points, anticipated depths if known, surface type, and access photos. Explain what decision the information must support: a crossing elevation, footing clearance, repair access, or another defined need.
J1S provides hydrovac excavation across Jefferson County and the St. Louis metro. For metro utility work, the St. Louis hydroexcavation page covers the service. Use the hydrovac quote checklist to organize the job details before requesting a price.