What to Know About Gas Lines Before You Dig for a Patio, Fence or Pool

Before you dig for a patio, fence, pool or any other yard project, you need to know where the gas lines run. Buried gas lines are often shallower than people expect, they are not always where you would guess, and striking one can lead to a leak, a fire or an explosion. The good news is that the safe way to dig is well established, it is free and it takes only a phone call or a website visit. This guide explains how to find out what is buried on your property, why utility marks do not always cover everything, how permits and planning fit in, and what to do if a line is damaged.

Why Digging Near Gas Lines Is Risky

Natural gas lines carry fuel under pressure, and even a small puncture can release gas into the soil and then into nearby buildings, trenches or crawl spaces. A line does not have to be cut in two to cause a problem. A scraped coating, a dented pipe or a loosened fitting can leak slowly and show up days or weeks later. Excavation work, from posthole digging to heavy equipment, puts buried lines at risk, and the person holding the shovel often has no idea what is a few inches below the surface. The risk is real for homeowners and for contractors alike, which is why careful planning matters.

Call 811 Before Any Digging

The first and most important step is to contact 811, the national call-before-you-dig number. It routes you to your regional notification center, which sends utility locators to mark the approximate location of their buried lines for free. In California, this is generally done through the regional one-call centers, and you can also request markings online. Requests are typically needed at least two working days before you dig, so build that wait into your schedule. This applies to every project that breaks the ground, including fence posts, planting trees, installing irrigation and installing a pool, even if you only plan to dig a few inches. Confirm the exact notice requirements when you call, since they can change.

What the Colored Markings Mean

After you call, locators mark the ground with paint or flags in standardized colors. Yellow is for gas, oil and other flammable materials, red is for electric, orange for communications, blue for water, green for sewer and drain, and pink for temporary survey marks. White marks the area where you plan to dig, which you can outline yourself before the locators arrive. Do not dig until the lines have been marked or you have confirmation that there are no conflicts. Keep the markings visible, and avoid mowing or hosing them away until the job is done.

The Marks Are Approximate

Utility markings show the approximate path of a line, not its exact location or depth. Most states, including California, define a tolerance zone on each side of the marked line, commonly about two feet, where you must dig with hand tools rather than machinery so the line can be exposed safely. Lines can curve, change depth or run in slightly different positions than the paint suggests. Treat the marks as a guide and not a guarantee, and expose the line by hand before using any equipment nearby.

Gas Lines Can Be Shallower Than You Think

Many people assume utilities are buried deep, but gas service lines can be surprisingly close to the surface. Depth depends on the original installation, the local requirements at the time, soil movement, erosion and later landscaping, and an older line may now be shallower than when it was installed. A fence post hole, a tree planting or even regrading a yard can reach a line that is only a foot or two below the ground. That is why even small, quick projects need a locate request.

Private Lines Are Often Not Marked

This is the part most homeowners miss. The utility's locate service typically marks only the lines the utility owns, which usually means the gas main and the service line up to the meter. Gas piping beyond the meter is generally the property owner's responsibility, and it may not be marked. That includes lines that run from the house to a grill, an outdoor kitchen, a fire pit, a pool or spa heater, a detached garage or a guesthouse. These private lines can run right through the area you are planning to dig, and a free locate request may not show them. If your property has any outdoor gas appliances or buildings, hire a private line locator or a licensed gas professional to find and mark those lines before you dig.

Know Your Property's Gas Layout First

Before you even call, it helps to know what gas equipment your property has. Look at where the meter sits, where the line enters the house and which outdoor appliances run on gas, and check any old plans, permits or inspection reports you may have. Pool heaters, barbecue stubs, outdoor fireplaces and gas lights all imply buried lines. If you bought the home recently, ask the previous owner or your contractor whether any outdoor gas lines were added. A few minutes of detective work can reveal where a line is likely to run and where it is safest to put the project.

Plan the Project Around the Lines

Knowing where the lines are lets you design around them. You can shift the fence line, move the patio footprint, choose a different spot for the pool or equipment, or plan to have a line rerouted before the work begins. Moving a gas line is not a casual job and should only be done by a licensed professional with the proper permits. Keep in mind that gas lines also need clearance from other structures, so building over a meter or on top of a line can create problems later, both for safety and for access when the line needs service.

Permits and Planning

Large projects like pools and patio covers usually require permits, and any gas work, including new outdoor appliance hookups or line relocation, typically does too. Permit requirements vary by city and county, and skipping them can lead to failed inspections, fines and trouble when you sell. Before you design anything, find out what applies to your project. Our guide to gas line permit requirements explains why permits are needed for gas work, what they cover and why they matter for safety.

Hiring Contractors for Digging Projects

If a contractor is doing the work, do not assume the 811 call has been made. Ask directly who is responsible for requesting the locate, ask to see the ticket number and check that the markings are on the ground before work starts. A reputable contractor will do this as a matter of routine, and it protects you as well as them. Make sure they know about any private gas lines that are not marked by the utility, and tell them about outdoor appliances, since they may not be aware of what is buried. Responsibility for damage can be costly, so it is worth being explicit.

If You Hit or Damage a Gas Line

If a line is struck, scraped or dented, stop work immediately and move away. Leave the area and take everyone with you, including pets, and stay upwind and well clear of the spot. Do not use lighters, matches, power tools or vehicles nearby, and do not try to cover, squeeze or repair the line. From a safe distance, call 911 and your gas utility's emergency number. Report the damage even if you do not smell gas or hear a hiss, since a damaged pipe or coating can leak later. Do not backfill the hole until the utility has inspected the line. Cutting corners here can turn a minor strike into a disaster.

Warning Signs After a Project

Sometimes damage is not noticed right away. After any digging near a line, stay alert for the signs of a leak, including a rotten-egg smell near the work area, a hissing sound, bubbling in wet soil or puddles, dead or dying plants along a line and a gas bill that climbs without explanation. If you notice any of these, leave the area and call for help. Our guide to the signs of gas line problems covers these clues and what each one may mean, and it is a good reference to keep in mind after any project near a buried line.

Be Careful With Trees, Irrigation and Drainage

Digging is not limited to big projects. Planting trees, installing irrigation, burying drainage lines or setting posts for a trellis all involve breaking ground. Tree roots can also grow around lines over time, and planting a large tree directly above a buried line can cause problems later. When you plan landscaping, consider where lines run and keep deep-rooted plants away from them. Also remember that digging the same spot years later is a risk, because markings fade and memories do not.

After the Project: Keep a Record

Once the work is finished, make a note of where the gas lines run on your property. Take photos of the open trench before it is covered, sketch a simple map and keep it with your permit and contractor paperwork. If you add new lines, ask the installer to mark their route in the records. Next time you plan a project, you will have a much clearer starting point, and so will any future owner.

When to Call a Professional

If you plan to dig anywhere near a gas line, if you have outdoor gas appliances, a pool heater or a detached building, or if you are not sure what is buried on your property, it is smart to have a professional locate and, if needed, relocate the lines before work begins. A licensed technician can inspect your system, trace private lines and make sure your plan does not put anyone at risk. In an emergency, always call 911 or the gas utility first. For inspection, installation, repair and relocation of gas lines, Golden Flame California Co serves homeowners across California, and you can reach us Mon–Fri 8am–6pm or Sat 9am–2pm. Have a sketch of your project, the location of the meter and a list of your gas appliances ready so the technician can get to the answer faster.