Excavation & Trenching
Working Around
Underground Utilities
Underground Utilities
811 Call Before You Dig · ConEd/DEP/ConEd Gas — All Must Be Located
New York City has one of the densest underground utility networks in the world — electric, gas, water, sewer, telecom, steam, and subway infrastructure all compete for the same narrow corridor under every block. Striking an underground utility during excavation can cause electrocution, gas explosion, and flooding simultaneously. Know the system, call before you dig, and never assume based on old drawings.
NYC 811 — Call Before You Dig
- New York 811 must be notified at least 2 full business days before ANY excavation — including hand digging
- After notification: utilities are field-marked within 2 business days using APWA color coding (red = electric, yellow = gas, blue = water, green = sewer, orange = telecom, purple = reclaimed water)
- Marks expire after 10 working days — if the schedule slips, call 811 again
- 811 marks are approximate locations (±18 inches from the mark) — hand dig within the tolerance zone before using mechanical equipment
When Mechanical Digging Must Stop
- Within 18 inches of any utility mark: stop the machine and switch to hand digging — pot-holing or vacuum excavation preferred
- Unexpected pipes, conduit, or cables encountered during excavation: stop all work, notify the utility owner, and have the utility identified before continuing
- Never assume "it must be abandoned" — abandoned utilities are not always documented or decommissioned
Striking a Utility — Emergency Response
- Electric strike: clear the area 100 feet minimum; call ConEd emergency 800-752-6633; call 911. Do not attempt to remove equipment from contact
- Gas strike: evacuate 300+ feet upwind; call ConEd Gas emergency 800-752-6633; call 911; eliminate all ignition sources
- Water main strike: shut the excavation access; call NYC DEP 718-337-4357; control access to the trench — water will erode soil rapidly
Discussion Questions
- How many business days before excavation must NYC 811 be notified, and when do the utility marks expire?
- You're excavating and strike what appears to be a conduit at 4 feet deep. There was no utility mark in this location. What do you do?
- Your backhoe operator sees the utility marks and says "we're 2 feet away — we're fine." What is the correct response?
- Who do you call if you strike a natural gas line during excavation, and what is the first action on site?
Sign-Off
Project Address
Date
Time
Foreman / Supervisor
SSM / SSC Name & License No.
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