Call 811 Before Digging: Your First Step in Deck Site Prep
Before you break ground on your deck project, you must call 811 to have underground utilities marked. This free service is required by law in all 50 states and could save your life. Hitting a gas line or electrical cable while digging post holes can be fatal.
Quick Summary
Time needed
15 minutes to call
Wait time
2-3 business days
Cost
Free
Why Calling 811 is Non-Negotiable
Every year, utility lines are struck over 400,000 times in the United States because someone decided to skip this step. The consequences range from a massive repair bill to house fires, explosions, and electrocutions. Even in rural areas, utility lines can run where you least expect them.
The risk is real: Natural gas lines can be as shallow as 12 inches underground. A post hole digger or auger can easily slice through a gas line, creating an immediate explosion hazard. Electric cables can electrocute you on contact.
The good news: 811 service is completely free. Utility companies will send technicians to mark their lines with color-coded paint or flags, usually within 2-3 business days. This simple phone call protects you, your family, and your neighbors.
What Utilities Get Marked
Marked by 811
- REDElectric power lines
- YELLOWNatural gas, oil, petroleum
- ORANGECable TV, phone, fiber optic
- BLUEPotable water lines
- GREENSewer and storm drains
- PURPLEReclaimed water, irrigation
NOT Marked by 811
- •Private propane lines — From tank to house
- •Septic system lines — Tank to drain field
- •Private well lines — Well to house
- •Sprinkler systems — Irrigation lines
- •Invisible pet fences — Buried wire
- •Landscape lighting — Low-voltage wiring
Important: 811 only marks utility lines up to your property line or meter. Private lines on your property are YOUR responsibility to locate. If you have propane, a well, or septic system, you may need to hire a private utility locator.
How to Call 811: Step-by-Step
1. Gather Your Information First
Before calling, have this information ready to make the process faster:
- •Your complete address including city and zip code
- •Description of where you'll be digging (e.g., "15 feet from back of house")
- •Type of work ("deck construction - digging post holes")
- •Planned start date (must be at least 2-3 business days out)
2. Call 811 or Submit Online
You have two options for submitting your locate request:
Phone
811
Available 24/7
Online
call811.com
Submit anytime, track status
The phone call typically takes 10-15 minutes. Online submission can be faster if you're comfortable describing the dig area precisely.
3. Mark Your Dig Area in White
While waiting for utilities to respond, mark the perimeter of your planned deck footprint with white paint or flags. This helps utility locators focus on the right area.
Pro tip: Mark a slightly larger area than your actual deck footprint. Give locators 3-5 extra feet on all sides so you have room to adjust post locations if needed.
4. Wait for Markings (2-3 Business Days)
Each utility company sends their own locator. You may see different people arriving over several days. Do not start digging until:
- •All utilities have marked their lines, OR
- •The waiting period has passed, OR
- •You receive "all clear" confirmation (no utilities in area)
5. Read and Photograph the Markings
Once marked, walk the site and understand what's underground:
- •Take photos of all markings before rain or foot traffic erases them
- •Note the direction and depth indicated (if any)
- •Plan post hole locations at least 18-24 inches from any marking
- •If a line runs directly through your deck area, call the utility company to discuss options
Common Mistakes to Avoid
Starting to dig before all utilities respond
Just because you see markings doesn't mean all utilities have responded. Each utility company works independently. Wait the full time period or verify all utilities have checked in.
Assuming rural properties have no utilities
Even remote properties often have underground electric, phone, or cable lines running across the yard. Transmission lines and pipelines can cross anywhere. Always call.
Forgetting about private utilities
811 does not mark private lines. If you have propane, a well, septic system, or irrigation, you need to locate those yourself or hire a private locator.
Digging directly on the markings
Utility markings have a tolerance of 18-24 inches on either side. The actual line could be anywhere within that zone. Hand dig carefully within 2 feet of any marking.
Frequently Asked Questions
Is calling 811 before digging really required by law?
Yes, calling 811 is legally required in all 50 states under federal law. Fines for failing to call can range from hundreds to thousands of dollars. If you damage a utility line, you're liable for repair costs, which can be tens of thousands of dollars.
How long does it take for utilities to be marked?
Most states require marking within 2-3 business days, though some allow up to 10 days. Check your state's specific requirements. Do not dig until the waiting period passes or all utilities confirm they've responded.
What do the colored flags and paint marks mean?
Red = electric. Yellow = gas/petroleum. Orange = communications (cable, phone). Blue = water. Green = sewer. Purple = reclaimed water. White = your proposed dig area. Pink = temporary survey marks.
Does 811 mark private utility lines?
No, 811 only marks public utility lines up to your meter or property line. Private lines like propane from your tank, well lines, septic pipes, and irrigation systems are your responsibility. Hire a private locator if needed.
Ready for the Next Step?
While waiting for utility markings, start checking for other underground obstacles that 811 won't mark, like septic systems and old wells.