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Ultimate Guide to Marking Flags: Why and How Surveyors Use Them
TLDR: If you find marking flags in your yard, they are most likely there to identify underground utilities, property boundaries, or planned construction work. Survey marking flags help surveyors, contractors, and utility crews work safely and accurately. Do not remove the flags, contact the company listed on them if you have questions, and call 811 if no contact information is available.
Key Takeaways:
Survey marking flags are used to identify underground utilities, property lines, and important reference points before digging or construction begins.
Different colored survey flags indicate different types of utilities or survey information, helping crews work safely and efficiently.
Removing survey marker flags can delay projects, create safety hazards, and increase the risk of damaging underground utility lines.
If you find surveying flags in your yard, leave them in place, contact the company listed on the flag, and wait for the work to be completed.
If you're a homeowner and find unfamiliar flags in or near your yard, your first thought might be, "What the heck are these things doing here?"
Stay calm. No need to call the sheriff. However, you may want to dial the number on the flag or 811 to find out why they're there.
Marking flags, or stake flags, are commonly used by surveyors, utility companies, landscapers, and contractors to identify, locate, and mark features on the land before digging or development begins.
These tools play a major role in keeping projects accurate, organized, and safe. Here’s what you should know.
What Are Marking Flags and Why Are They Used?
Marking flags are brightly colored flags attached to thin metal rods or plastic staffs. Many are made with durable poly or vinyl materials. These highly visible markers are designed to withstand outdoor conditions while remaining easy to spot from a distance.
Surveyors use marking flags to identify survey points, underground utilities, boundary lines, easements, and potential hazards. Utility companies and contractors also rely on survey flagging to map out work areas before excavation begins.
By using survey marking flags, crews can:
Improve measurement accuracy
Prevent accidental digging damage
Clearly communicate work zones
Increase jobsite efficiency
Reduce costly mistakes and delays
Someone in your area may be planning excavation work to renovate or add features to a property. That could be your neighbor, your neighbor's contractor, a utility company, or your local city or county government.
From installing a new pool to repairing underground cables or adding utility poles, many projects require a flag survey before work can safely begin.
Common Survey Flag Colors and What They Mean
Different survey flags colors typically represent different utilities or purposes. While colors can vary slightly by region or company, here are some of the most common meanings:
Red flags: Electric power lines, cables, or lighting wires
Orange flags: Communication lines, cable TV, or fiber optics
Yellow flags: Gas, oil, steam, or petroleum lines
Blue flags: Potable water lines
Green flags: Sewer and drain lines
Pink flags: Temporary survey markings or unknown survey points
White flags: Proposed excavation areas
These color-coded marker flags help workers quickly identify what is underground before excavation starts.
Obtain Accurate Measurements
One of the primary reasons surveyors use survey flags is to obtain accurate and consistent measurements. By marking property corners, elevation points, underground utilities, and boundary lines, surveyors can ensure land development projects stay compliant and on track.
Without proper survey flagging, crews could accidentally measure from the wrong point, leading to costly errors, project delays, or even property disputes.
Poly flags are especially useful because they are lightweight, durable, weather-resistant, and highly visible in grass, dirt, gravel, and construction areas.
Efficiency on the Jobsite
Marking flags allow contractors, land developers, and utility crews to work more efficiently by clearly identifying the locations of key features. Instead of constantly remeasuring or second-guessing locations, crews can quickly identify marked points and continue working safely.
Using stake flags also helps multiple teams coordinate work on the same project. For example, surveyors may place flags first, utility locators may follow, and excavation crews can then safely begin digging.
This organized process saves time, reduces confusion, and lowers the risk of damaging underground infrastructure.
What Should You Do If You Find Marking Flags in Your Yard?
If you find survey flags in your yard, there are a few important steps you should follow.
1. Don’t Remove Them
Please! The first thing you should do is leave the marking flags exactly where they are.
Removing survey flags can create safety hazards, delay projects, or make it difficult for surveyors and utility crews to relocate important points. In some cases, removing flags could even increase the risk of damaging underground utility lines.
Leaving the flags in place helps ensure work can be completed efficiently and safely.
2. Contact the Surveyor or Utility Company
The company’s contact information is often printed directly on the flag or attached tag. Reach out to ask about the purpose of the markings and when the work is expected to be completed.
If you cannot find a phone number or website, dialing 811 is the next best step. The 811 service can help identify utility marking activity in your area.
3. Mark the Area if Necessary
While waiting for crews to finish their work, you may want to make the flagged areas easier to see so they are not accidentally disturbed.
For example, if you are mowing your lawn or hosting outdoor activities, you can place temporary visual reminders nearby to help avoid damaging or removing the survey flags.
Be careful not to move or alter the original flag survey markers themselves.
4. Be Patient
Surveyors and utility crews may need several days to complete their work. Depending on the size and complexity of the project, surveying flags may remain in place for an extended period.
Once the project is complete, crews will typically remove the marking flags and restore the area as needed.
Trust Blackburn for Durable Survey Flags and Marking Products
Blackburn offers durable marking products designed to help crews work safely and efficiently. Blackburn’s utility flags are available in both poly and vinyl materials, with plain, patterned, and custom printed options to fit a wide range of jobsite needs and visibility requirements.
Whether you're a contractor, utility locator, surveyor, or municipality, having dependable survey flagging products can make all the difference on the jobsite.
Explore Blackburn’s full selection of survey marking flags and marking products to keep your next project organized, visible, and compliant.
FAQs
What are survey marking flags used for?
Survey marking flags are used to identify underground utilities, property boundaries, excavation zones, and important reference points before construction or digging projects begin.
What do different colored survey flags mean?
Different survey flags colors represent different utilities or purposes. For example, red flags often indicate electric lines, yellow flags mark gas lines, and blue flags identify water lines.
Can I remove survey flags from my yard?
No. You should avoid removing marking flags because they help utility crews and surveyors safely complete their work. Removing them could create safety risks or delay a project.
How long do surveying flags stay in place?
Surveying flags may remain in place for several days or weeks depending on the project timeline. Crews usually remove the flags once the work is completed. Call the number on the flag or 811 for more information.
What should I do if I accidentally remove a survey flag?
If a survey flag is accidentally removed or damaged, contact the surveyor, contractor, or utility company listed on the flag as soon as possible so they can remark the area.
What are poly flags?
A poly flag is a durable plastic marking flag commonly used in surveying, construction, landscaping, and utility marking. They are weather-resistant, lightweight, and highly visible.
Why would there be survey flags in my neighborhood?
Survey flags may appear in neighborhoods before utility repairs, road work, landscaping projects, new construction, fiber optic installation, or property surveys.
