Home Improvement Outdoors

How to Avoid Utility Lines When Digging in Your Yard

Trench-digging
Monty Rakusen / Getty Images

Your property is interlaced with utility lines crisscrossing at various levels: electric lines, low voltage lines, water, cable, sewer, natural gas, and more. Digging on your property can lead to an expensive or dangerous mishap if you cut into one of these lines. Fortunately, there are effective, free methods of pinpointing the location of underground utility lines before you dig.

How Deep Electrical Lines Are Buried

All utility lines are a concern when digging on the property, but electrical lines are of the most concern. Buried electrical line depths can range from common lines like low voltage electrical wires for pathway lighting up to less common lines like high power underground distribution lines running through easements.

  • Depth of low voltage wire: Loose wires for pathway lighting might be 1 to 2 inches deep or might even be on ground level. Most low-voltage lines up to 30 volts should be buried at a depth of 6 inches or greater.
  • Depth of electric lines on property: Most electric lines on properties are buried between 24 inches (more common) and even up to 48 inches deep.
  • Depth of high voltage cables: High voltage cables between 22,001 and 40,000 volts should be buried to a depth of 36 inches or deeper. Cables carrying 40,001 volts and more will be buried at 42 inches or greater. If found on the property, these lines should run through utility easements.

Tip

Contacting your local utility marking service might be more than just a good idea. Many states have "dig laws" that legally require you to call the service before digging in your yard.

Reasons to Call 811 Utility Marking Services

  • Creating a garden pond
  • Planting a tree
  • Digging up the yard for a sewer trench
  • Digging fence post holes
  • Digging foundations for a deck, shed, or garage
  • Trenching a base for an intended retaining wall
  • Digging up parts of your lawn to install an irrigation system
  • Trenching your yard to add conduit for an exterior outlet or light
  • Creating trenches for drainage lines such as for French drains
  • Adding a patio
  • Building a carport

Utility Lines Marked vs. Not Marked

When a locating service visits your property, some utilities are marked by the service and other utilities are not.

Usually Marked

  • Electrical service wires
  • Cable TV or internet service wires
  • Telephone service wires
  • Sewer and water mains
  • Natural gas supply pipes

Usually Not Marked

  • Security systems
  • Lawn irrigation systems
  • Line voltage (120-volt) landscape lighting systems
  • Low-voltage landscape lighting wires
  • Electrical conduits or underground cables running to pools and spas or to buried septic tanks

Can You Find Utility Lines by Yourself?

You can locate the general direction of utility lines by yourself, but you should always confirm with a locating service before digging.

Over time, as services are added to the house, trenches are dug and earth or sod are laid over the top. Unless marked, trench locations are quickly forgotten. When a home passes from one owner to another, the locations of these utility lines are rarely communicated to the new owner.

Buried depth requirements of these utilities can vary from area to area. In colder climates, sewer and water lines are typically deep in the ground below the winter frost line. Homeowners may dig shallow trenches for irrigation piping or for low-voltage landscape lighting. Often, utility line depth is less a matter of prescribed requirements and more a matter of whim.

The same homeowner who moves to a warm climate, though, can be startled to find that water and sewer pipes are quite shallow. And over the years, utilities are added and canceled, so that you may find that active telephone wires for landlines are still present in your yard, even though you long ago transitioned to cell service for all your telephone needs.

How to Find Utility Lines by Yourself

One way to find the general location of a utility line is to look for its start and end points, then draw a mental line between the two points. This method approximates the location of the utility line and is not a reliable indicator of the line's exact location.

For example, to locate the general path of the water line from the street to your house, first locate the point on the street where the water line enters your yard. Usually, this is the water meter.

Next, find the point where the water line enters your house. Think of a straight line between the two points to get a general sense of where the water line runs across your yard.

This method is not conclusive. While it's ideal to bring a wire or pipe in a straight line, this may not always be the case. If the wire or pipe approaches a major obstruction like a garden pond or foundation footers, it will detour around the obstruction.

Warning

Approximating the location of the utility line is just that: approximate. Always find the location of a utility line by having the local 811 service visit your property and marking for utilities. Never try to locate a utility line by probing the ground.

How to Contact 811 Utility Mark System

When you call 811, the process works like this:

  1. Call 811 before you dig.
  2. Your phone call will be routed to a central call center.
  3. Answer the dispatcher's questions regarding the nature of your planned digging project.
  4. The dispatcher will reach out and contact any public utilities in your area that might be affected by your digging project. In some cases, the actual location and marking will be done by private companies working under contract with the utility companies. In other instances, it will be employees of the utility company who do the work.
  5. Before the 811 technician visits your home, make sure that they have full access to the exterior. Bring dogs inside or chain them up, unlock gates, and turn off exterior security devices.
  6. Workers will visit your property and mark the ground with paint or flags to indicate the location of underground utility wires and pipes.
  7. The markings are regarded as valid for about one month after they are marked since the water-soluble paint can wash off over time. Wait until all utilities have been marked before you start digging. If your work will not begin for 30 days or more after the initial marking, you should call 811 again and have the marking repeated.

Tip

In 2005, the U.S. federal government made 811 the national number to call for alerting different regional services that coordinate location activities for underground public utilities throughout the country. In most areas, the service is known as "Call Before You Dig" but is known as "Dig Safe" in the New England region.

Typical Utility Line Color Codes

  • White: Proposed excavation
  • Pink: Survey markings
  • Red: Electric
  • Yellow: Gas, oil, steam
  • Orange: Communications, alarms
  • Blue: Potable water
  • Purple: Reclaimed water, irrigation
  • Green: Sewer

Limitations of 811 Utility Location Service

This free 811 coordination service will mark the location of utilities up to the point where the lines make their initial connection to the home or service meter. If these lines continue underground—such as from a house to a detached garage or shed—the 811 coordination service does not pinpoint the location of these secondary lines. These secondary lines are considered to be the owner's property, not the utility company's.

Also, 811 does not coordinate location services for any service wires or pipes that are not considered public utilities or which have been installed by private companies.

The 811 utility location service only identifies underground services. For example, municipal power that enters the home through the service drop is not part of the 811 program.

Where private companies have installed underground pipes or cables, contact the company and ask for assistance in locating them. In some instances, you will be charged for this service.

How Far in Advance to Call 811?

Call about three days or more before you plan to dig to give the service enough time to schedule you. The lead time required varies from region to region.

Do not call more than 30 days before you begin your project. Temporary marking paint typically has a 30 day limit before it washes away or fades.

Regional Services

In some areas there are aggregated services similar to the nationwide one—but on a smaller, regional scale. A few of the larger services:

Individual states often maintain web portals providing information on safe digging. They are easily found by typing "811 (state name)" in the browser window.

These regional and state services are now generally coordinated with the national 811 service, but they may offer additional services. For example, the local aggregated services may let you schedule on-line, or they may put you in touch with private location services who, for an additional fee, can locate and mark any private utility lines on your property that are not covered by 811. These web sites also offer a wealth of information on how to plan and execute a safe excavation.

Tips for Digging Around Utility Lines

  • Keep your trenches or holes at least 18 inches away from 811 markings. The tools used to locate underground wires are not always precise, and 811 guidelines say that holes or trenches should be kept at least 18 inches away from either side of marked lines.
  • If you have installed underground wires or pipes yourself, consult your notes to determine their location. Most irrigation pipes and low-voltage cables will be fairly shallow, so digging a series of test holes by hand can help you locate them.
  • There are private location services that will inspect your property for a fee and locate any underground pipes, conduits, and wires. This is especially helpful for non-public utility lines that were installed by private companies.
  • Dig slowly. Irrigation lines and landscape lighting conduits and cables are not identified by 811 location services, so dig methodically and slowly, examining the excavation regularly for unexpected pipes and cables.
The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Depth Requirements for Buried Electrical Cable. Gateway Cable Company

  2. How deep is the electric line buried on my property? Lewis County Public Utilities District

  3. 220 CMR 126.00: Underground Electric Supply and Communication Lines. State of Massachusetts