Planting trees -- how far from underground sewer line? (irrigation, grow, Dogwood)

[HB2HSV]

I have the underground sewer line runs out of my front yard to the city sewer on the street side. It's pretty deep, probably at least 5 ~ 6 feet or more. I am thinking planting trees (maple, redbud, or even japanese maple) near that area. How far back should I plan for the roots so as to not to penetrate those PVC sewer pipes?

Thanks.

[caution]

roots won't grow in to PVC pipe, in fact one solution for roots invading the old clay pipe is PVC casing.

if you were really worried about it, 10-15 feet for the redbud and japanese maple and a bit more for the red maple (or other non-invasive maple cultivar).

of course, over the long term, i suppose the large roots of some trees could, at least in theory push on the pipes and somehow heave them out of place or crush them, i guess if they were right on top of it or right beside it

[checking out]

Depends on the type of tree. Some have roots that don't grow deep or invasive, such as dogwoods.

They DO grow into PVC pipe, especially at the joints.

[caution]

hmm never seen one grow into pvc pipe or the joint, but i suppose in nature v. plastic that nature will eventually win

is it becuase sewer lines aren't under pressure?

[si33]

Agreed, much will depend on the type/species of tree chosen..

Smaller trees like crape myrtle generally have smaller root systems in comparison to something like an oak or maple whose roots can seek out something like a sewer line during times of drought..especially if the tree was not correctly established (ie: it did not get a regular deep soaking to help establish a deep root system..)

Here in CA. we usually have trouble with trees like poplars, silver maple, box elder and plane trees..

As for pvc pipes?. tree roots will also penetrate these with time...especially larger or greedy rooting species....

[harry chickpea]

6' down is not much of an issue. A tap root goes straight down (more or less) and feeder roots are commonly within the top couple of feet. To be on the safe side, I'd find the average crown width of the adult tree, and go between 1/4 to 1/2 of that figure as the distance from the tree bole to the sewer line.

[mdvaden]

Originally Posted by caution

hmm never seen one grow into pvc pipe or the joint, but i suppose in nature v. plastic that nature will eventually win

is it becuase sewer lines aren't under pressure?

I have never seen roots get into a properly sealed PVC joint either - not a glued fitting anyway. And that after 30 years in this trade, including several country clubs with weekly or daily line repairs.

Some tree worker posted a photo or mentioned a photo shown at a trade seminar, of a root entering a line, but that's exceedingly an exception. And I don't think it was a PVC or similar pipe either. If a fitting is glued so that pressurized water can't escape or leak, how will a root penetrate?

Consider how many irrigation and city water lines and meters are located near trees by sidewalk areas and leading into homes and buildings? On occassion a big tree will break a pipe, but in my lifetime, I don't expect to see a tree root penetrate a sealed glued fitting.

Slip or compression joint - maybe, but still have not seen it.

For my own needs, I'd have no problem with planting a Japanese maple directly over a sewer line at our home, especially if it was several feet deep.

Probably would not plant something like a big red maple or scarlet oak right over it, but maybe 8' or more to the side.

M. D. Vaden of Oregon

Certified Arborist

[Dale245]

Depends on the quality of the joint. If the joint was properly primed and glued with pvc glue (705) then I dont see roots getting in unless the pipe settles and cracks.

[wit-nit]

Large trees planted over or very near PVC piping will eventually crack or break the PVC connections due to the weight of the tree and the expansion of the trees root system. Then the roots will have a new water source and you will have a huge repair bill. Something has to give, and the PVC is the most susceptible.

[Gloria Naha]

Planting trees are being discouraged around our neighborhood because of the concrete sewer lines. Are there any trees that I can plant that won't dig into the concrete sewer lines?