How do I plan landscaping without hurting plumbing lines?

Arizona 811 states the rule for homeowners and renters alike: notify them at least two full working days before you start any project, "such as planting a tree, installing a fence or other projects that require any type of excavation." The two days exclude weekends and state-recognized holidays. The call is free. You can phone 811 Monday through Friday from 6 a.m. to 5 p.m., or create a ticket online at any hour.

Even a small hole counts. UniSource Energy Services warns that even shallow digging to plant flowers, trees or shrubs, or to set a post, can damage a utility line, and that you should not assume you know where lines run or how deep they are. A 2022 survey by the Common Ground Alliance, which UniSource cites, found that nearly half of U.S. homeowners planning a dig did not plan to call 811 first.

Here is how the process works, in the order Arizona 811 gives it:

1. 1Create the ticket at least two full working days ahead.
2. 2Mark your dig site in white paint or flags. Arizona 811 says to use only white for this.
3. 3Wait for every response. Locators have two full working days. Do not dig until you have heard from all of the operators listed on your ticket. If the deadline passes with responses missing, call 811 and ask for a Priority Notice.
4. 4Read the marks. An operator either paints its lines in the color for that utility or answers "No Conflict," meaning it owns nothing at your site.
5. 5Hand-dig near the marks. Arizona law requires hand digging within two feet of marked facilities. Keep the marks visible for the whole project.

The Arizona Corporation Commission, which enforces the state's Underground Facilities Law, says a contractor or homeowner cannot begin excavating until all utilities have been marked, or faces a maximum fine of $5,000 per violation. The same page says utility owners must mark their facilities within 48 hours. Treat the call as part of the landscaping job, not an extra.

This is the part that catches homeowners out. Arizona 811 explains that utility companies and local governments mark only what they own and operate up to their point of service, which is typically the meter. It names two examples of private lines an owner might have: a water line to a pool and a gas line to a backyard barbecue. If you own such lines, or suspect they are buried in your yard, it suggests hiring a private locating company.

Your yard may hold more private plumbing than you remember. Think through this list before you draw a plan:

• The sewer lateral. It runs from the house to the city main and belongs to the owner. The cleanout marks a point on it. See what a sewer cleanout is and who is responsible for the sewer line in Phoenix.
• The water service line from the meter to the house, and any branch to a pool, an outdoor kitchen or a guest house.
• Irrigation lines and valve boxes. A shovel through a buried sprinkler line is a very common yard mistake, and a leak that follows can hide for a long time. If a line does get nicked, how to fix drip irrigation covers the small repairs.
• A gas line to a grill, fire pit or pool heater.
• Drain lines from a downspout, a pool backwash or an outdoor sink.

If you do not have as-built drawings, the fastest clues are the cleanout, the water shutoff, the meter box and the places where lines leave the house. A plumber can trace a line with a camera and a locator. Our page on what a plumbing camera inspection can find describes what the plumber can show you about the sewer side.

Trees are the most common way a landscape plan damages plumbing, and the damage arrives slowly. Roots do not cut through healthy pipe. They follow moisture that escapes through a crack or loose joint, then thicken. Our page on how roots destroy pipes in Mesa and Chandler yards walks through the steps.

Use these limits when you choose a planting spot. A yard plan is only as good as the pipe map behind it:

• Sewer line. Mesa's wastewater guidance says to plant trees more than 10 feet away from sewer lines. Treat that as a floor. A Pima County Cooperative Extension agent quoted in the Arizona Daily Star says mature tree roots typically reach 2 to 3 times the width of the crown.
• Cleanout. Phoenix advises against planting a tree or large shrub over or near the sewer line or the cleanout. Keep the cleanout uncovered so a plumber can reach it without digging.
• The house. Phoenix also advises keeping trees and large shrubs from growing so near the house that roots can invade the foundation.

In a Q&A in the Arizona Daily Star, a Pima County Cooperative Extension agent said sewer pipes are at risk with tree roots nearby, and that the answer is to measure your space and plan for the mature size of the tree. The agent's low water use suggestions were white thorn acacia, ironwood, Texas ebony and, where space is tight, desert willow, and the agent added that even native desert species need some water. The article does not rank trees by root risk, so choose by mature size and distance from the line, not the size in the nursery pot.

A good landscape leaves room for the plumber to work. Three spots deserve their own plan:

The water shutoff and meter box. Phoenix Water Services says every household should know where its shutoff valve is and test it regularly, and that for most houses it sits near the front of the home, close to a hose bib. The city also says not to shut the water off at the meter, because that takes a special tool and you may be held responsible for damage to the meter. Keep both places free of boulders, thorny plants and pavers so you can reach them in a hurry.

The cleanout. Do not bury it under mulch, rock or a planter. If you cannot find yours, maintaining your sewer line to prevent backups explains why to locate it before a problem, not during one.

The hose bibs and irrigation backflow assembly. These need room around them for repairs and testing. Read what a hose bib vacuum breaker is and the backflow preventer rules for sprinklers in Arizona before you build a wall or planter around them.

### Three examples of how a plan can go wrong

These are made-up examples to show the pattern, not real jobs.

A shade tree over the sewer line. A homeowner plants a mesquite 6 feet from the lateral because it is the only sunny-side gap. Nothing shows for years. Then drains slow, a camera shows roots at a joint, and the choice becomes a repair or removal of the tree. Moving the planting spot costs nothing on day one.

A post hole through a pool line. A homeowner calls 811 for a fence, and the utilities mark their lines. The pool's water line is private and unmarked, and the post hole hits it. The call was made, but nobody marked the private line. A private locate would have shown it.

A paver patio over the cleanout. The patio looks great until a sewer backup. A plumber cannot reach the cleanout, so the pavers come up first. Leaving a small access lid at the start would have avoided it.

UniSource says if you think you damaged a utility line, call 911 right away if there is danger, and call 811 to report the damage however minor it seems. It also says never to bury the line or try to repair it yourself. For a water line, shut off the water at your main shutoff valve, not the meter, and call a plumber. The Phoenix tips sheet says the same about a broken pipe: turn off the water at the main shutoff and call a plumber. A leak that no one has spotted shows up on the bill, so read how to do a water meter leak test if usage rises after a project.

HQ Plumbing offers free estimates and upfront pricing, and can trace and camera your lines before you put in trees, a patio or a pool. If a grass-to-xeriscape rebate is part of the plan, Mesa's water and energy rebates explains that city's incentive rules.