Pittsburgh Sycamore Tree Sewer Damage: When Roots Meet a Lateral

Pittsburgh sycamore tree sewer damage became a local news story this year, when WPXI reported that a roughly 200-year-old sycamore in East Liberty had crushed a homeowner's sewer line. The report is unusual in scale, but the mechanism behind it is a common one that utilities describe in plain terms.

This post sticks to what that reporting said and what Pittsburgh-area and other utility sources say about tree roots and sewer pipes. It makes no claim about any particular species or any particular street.

The story as reported

WPXI reported in May that the tree's roots were lifting slabs of concrete and that the crushed line left the homeowner without a working sewer. A follow-up in July said the repair, done about 13 feet underground by a plumbing company, was finished after the city helped coordinate the tree's removal. The reports describe a household that could not use its shower, dishwasher or washer and dryer while the line was down.

That was a failed sewer line, not a sewage backup into a basement. It shows, though, how a root problem can leave a house with nowhere for its wastewater to go.

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Large tree with peeling mottled bark whose thick roots have lifted and cracked concrete sidewalk slabs beside a leaf-covered lawn.

Roots and old pipes, according to utilities

Pittsburgh Water lists cracks due to tree roots among the causes of sewage backups, next to grease, hair and solid buildup. A sewer authority in Oregon describes the process: roots can tangle with tissue, grease and debris inside a pipe, and as they grow they put pressure on the pipe, which can crack or collapse. Naperville, Illinois ranks roots first among its backup causes, describing roots that seek moisture and enter cracks.

DC Water's brochure adds that a blockage worsens over time, since roots that find moisture keep growing. 3 Rivers Wet Weather says laterals can become deteriorated through age or settling and clogged with tree roots.

Who answers for the lateral

Pittsburgh Water hands the entire sewer lateral to the property owner, residential or commercial, and keeps the main plus a short piece at the junction for itself. Its backup page also places a broken or clogged lateral with the owner. For the Pittsburgh steps when a backup does happen, see Pittsburgh's opening-steps page.

Readers in other towns should check locally, since 3 Rivers Wet Weather reports that the dividing line differs between communities.

Planting with the pipe in mind

Utilities that mention trees offer similar advice about distance:

  • DC Water suggests planting trees several feet away from sewer laterals.
  • Denver's flood handbook attaches a distance: trees and shrubs ten feet or more from the line, it says, limit root harm.
  • DC Water also suggests having a plumber clean the lateral at regular intervals.

None of these sources says a large old tree must come down, and the news story is not evidence of how often that happens.

If the roots win

A pipe crushed or blocked by roots is a repair, and the repair belongs to a plumber. What follows when wastewater has reached a floor is a cleanup, which is a different trade. A post on other backup causes puts roots among the rest, and a separate one asks who answers for which pipe.

The people behind this website refer jobs; they run no cleanup crew. If wastewater has reached the house, the Contact Us page passes details to a contractor near it.

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Common questions

The WPXI reports describe a crushed sewer line and a household without working plumbing, not a sewage backup into a home.
The owner, by Pittsburgh Water's account. The authority keeps the main and a short piece at the junction, and everything from there to the house is the property owner's.
The sources describe roots entering cracks and growing there, and DC Water adds that roots keep growing once they locate moisture.