Call Before You Dig

Call Before You Dig

Frequently Asked Questions

1. I called 811 and waited two full business days, now what?

You are required to give Maryland One Call at least two full business days’ notice before any excavation or demolition begins.  Once you are within the legal start dates, check your responses via phone, email, or the communication method you had previously chosen to notify Maryland One Call.  You should either have a “Clear” or “Marked” response from each individual utility.  If you have not yet received a response from a particular utility, please re-notify Maryland One Call immediately and specify the utility that has not yet responded.  Do not assume it is safe to dig because there was no response.

2. I checked my responses through Maryland One Call. What do they mean?

Marked – There are underground facilities in the area.  Use caution when digging around the marked lines.  In Maryland, there is an 18” tolerance zone.  That means, within 18” on either side of the marks, plus the diameter of the facility ONLY hand digging practices may be used to expose the line.  NO powered equipment can be used within this area. 

Clear – The utility that responded with a clear status does not have any underground utilities in the area where you have stated you will be working.  If the work area expands or changes, you should call in a new ticket with the updated information.

Conflict, Direct Contact to Follow – Do not dig. There was potentially an issue while attempting to mark your facilities.  Wait for a representative from that utility company to contact you with more information or call Maryland One Call for more information..

Not marked due to no access – Do not dig. The utility locator was unable to gain access to the property where the work will be done.  This may be a result of a dog, gated community, fence or locked gate.  Make sure you have arrangements to allow for access to the property. 

Delayed – Do not dig. The utility that responded with a delayed status was unable to mark your facilities within the allotted timeframe.  This can occur from various unforeseen issues including weather, heavy ticket volume or other obstacles that appear throughout the course of a routine business day.

Insufficient information - Do not dig. The utility was not given enough information to know exactly where to mark the lines. Wait for a representative from that utility company to contact you with more information or call Maryland One Call for more information.

3. After I called One Call, my property was marked with all different colors.  What do they mean?  

No matter what state you live in, the colors you see painted will represent the same information.  The American Public Works Association (APWA) has come up with a uniformed color code that can easily be interpreted by homeowner and excavators alike.  The colors are as follows:

Blue – Potable Water
Purple – Reclaimed Water, Irrigation and Slurry Lines
Pink – Temporary Survey Markings
Red – Electric Power Lines, Cable, Conduit and Lighting Cables
Yellow – Gas, Oil, Stream, Petroleum or Gaseous Materials
Orange – Communication, Alarm or Signal Lines, Cables or Conduit
Green – Sewers and Drain lines
White – Proposed Excavation

4. I hand dug to expose the marked facility, can I use powered equipment?

No.  Theoretically, the tolerance zone expands infinitely beneath the surface.  There are many instances where the first line you expose may not be the line in use at that property.  Exposing what you believe to be the actual line may in fact be a line that has been abandoned years ago.  The “live” line that is currently in use may be lying only inches away still hidden beneath the earth.   Disastrous situations can be avoided by following all best practices as set forth in Act 287 and as recommended by The Common Ground Alliance. 

5. What do I do if I damage an underground gas line? 

If gas is blowing, you must immediately leave the area and call 911. Then call Columbia Gas at 1-888-460-4332. Do NOT attempt to restrict the flow of gas!  There may be a hidden secondary damage that can be worsened as a result of the pressure building once you attempt to stop the leak.  Stay clear of the area.  Do not get in the excavation area.  If safe, turn off the equipment and try to eliminate potential ignition sources.   The first priority is the protection of life.  After 911 has been notified, you may also contact Maryland One Call. 

6. What do I do if I scrape, dent or gouge an underground gas line? 

Call Columbia Gas at 1-888-460-4332. Gas does not have to be blowing for there to be damage to the line. A Service Technician will respond to evaluate the extent of the damage caused by the scrape, dent, or gouge to the pipe and pipe coating.

7. Will the locators need to gain access into my home?

Typically, the person marking your facilities will not need to come into your home.  On occasion, it may be necessary for an employee to enter your home to find and verify your lines.  Each employee will have an ID badge and you can always contact Columbia Gas to verify the identity and purpose of the visit.

8. How deep is the gas line?

The depth of the gas line varies from location to location and is based on a number of factors.  There is no way to know the precise depth of a gas line that is buried underground, which is why it is so important to call 811 for a locate to have the facility owners mark the lines.  Always be sure to expose gas lines by hand digging when working on your project.

9. I called 811 and had a mark-out done, but through the course of my work the marks have been destroyed.  What should I do now?

As a safe excavator, it is your responsibility to preserve the marks that have been placed on the ground.  However, sometimes the work does not always allow this to happen.  If the marks from your mark-out are no longer visible, dial 811 to re-notify utilities to come back out and re-mark their lines.

10. Do I need to call 811 if I plan to demolish a building?

Yes, a valid One Call is needed if you plan on doing any demolition work.  Demolition can affect underground utilities, especially if there are service lines in the area.

11. I placed a One Call and all of the facilities are marked out, but I have not started the work before the expiration date on the ticket.  Do I need to call again?

Yes.  If you have not started the work before the ticket expires, the ticket is no longer valid.  You must call and place a new One Call. Refer to your One Call ticket for lawful start dates if you’re unsure.

12. Do I have to call if I am digging on my own property?

Yes, you are required to inform the utilities of any type of work involving the movement of earth with powered equipment.

13. Who should make the call?

The person who is doing the digging should place the One Call notification. If you are a homeowner and you've hired an excavator to do the work, the excavator is required by law to call to have lines located (refer to MD code title 12 Subsection 12 – 124 [Appendix A]).

14. How deep must I dig before I am required to call?

The only sure way you will know where underground utilties are located is to place a One Call. Therefore, it is advised, no matter the depth of digging, to place a One Call. If you are digging with any type of powered equipment, the person operating the equipment is required to call, no matter how deep you are digging or where you are digging within the Maryland.

15. What are Maryland One Call's hours of operations?

The call center is open 24-hours a day, 7 days a week, every day of the year.

16. Who marks the lines?

Each member utility owner is responsible for sending someone to the site to mark their underground lines. Some utility owners send their own employees while others hire professional locating companies to do it. Maryland One Call System does not mark the lines. 

17. Do I have to call every 10 days if I am still working on the site?

Yes, you must call on the 10th day. It is the excavator's responsibility to maintain the marks. Marks that have been removed, moved or otherwise tampered with are never accurate and prove to be deadly.

18. I have yellow marks and/or yellow flags on my property, what do they mean?

Prior to any excavation or demolition project using powered equipment, Maryland law requires a call be made to the state One Call notification center by dialing 811. This call sends notification to all utility operators owning utility lines within the proposed work area. To prevent damage and the possibility of serious consequences that can result from a utility damage, all utility owners are required to mark the approximate location within 18 inches and within three business days upon receipt of the call. Columbia Gas marks with yellow paint, flags, stakes or a combination thereof indicating there are gas lines below. These marks are not an indication of depth. For more information on digging safely around these markings, please contact your local One Call notification center at 811.