Step #4: Understanding the Marks
You’ve notified Missouri One Call. You then waited the required amount of time and confirmed each utilities response. Your dig site should now be marked with various colors and flags. It’s important to understand what these marks mean.
Each utility type has been assigned a color. The marks and flags at your dig site were put there by the utilities locator designating what facilities are underground in the area where you will be digging. These marks are color coded.
If you remember, you used white to mark your proposed dig site. Red is the color used for electric lines. Yellow shows gas, oil, steam, petroleum or gaseous materials. Orange markings will indicate that there is some sort of communications cables below. It could be cable television, a phone line or fiber optics. Blue is the marking for water lines. Purple is used to mark reclaimed water, irrigation and slurry lines. Green is for sewers and drains. Pink is used for temporary survey markings.
Each marking should indicate the utility it represents and also shows the facility size and material, along with the direction of the line. Please note that once you’re on the job site, it is your responsibility to protect these marks. Remember, these marks are your guide to a safe and successful damage free excavation. If the markings get damaged or are no longer visible, stop and notify Missouri One Call to request a remark.
Locating underground facilities is not an exact science. The type of facilities, their depth and a variety of other factors can make it difficult to exactly mark the location of underground utilities.
Because of the difficulties with locating underground facilities, each utility is allowed a buffer zone of 2 feet on either side of the utility called an “Approximate Location” in Missouri law. By definition in the law, an Approximate Location is a strip of land not wider than the width of the underground facility, plus two feet on either side thereof.
For example, if the underground facility happens to be a 12 inch pipe, then the total width of the approximate location is 5 feet. If it’s a one inch wide cable, the width is 4 feet, 1inch. Hand digging within the Approximate Location to expose the facility before proceeding with mechanical equipment is highly recommended.
Landscaping and erosion can change the installed depth of an underground facility. You should never assume the depth of any facility. One of the most common causes of damages occurs when the excavator assumes the depth of a facility and mechanically digs within the approximate location area. Underground utilities might be closer to the surface than you think. Taking “just one scoop off of the top” is one of the main reasons damages occur.
Keep in mind, utilities will mark the underground facilities they own, usually up to the meter. Facilities from the meter into the house are privately owned and as a rule, are not marked by the utilities. It is the excavators responsibility to determine where these private facilities are located.
Remember to respect the marks and always use safe digging practices. Dig safely. It’s the law.