Yes, sewer piping has to be compromised for tree roots to get in. The City
of Durham, NC has some interesting info and offers another solution besides
snaking or augering the roots out:
"Tree roots are opportunistic. While they will not crack a sound sewer
service or water line, they will exploit cracks or failures in the lines.
The best defense against having tree roots in lines is to make sure that
your lines are in good condition and that they're not cracked. If you
suspect that tree roots are growing into your sewer line, you can have the
roots cut out using a process called "rodding". You can also flush Copper
Sulfate down the toilet two to three times per year to prevent roots from
growing into sewer lines. Copper Sulfate is an inexpensive chemical that can
be purchased at most hardware stores."

BTW, I've heard that copper sulfate is quite effective.

Suzy O
"Rod & Betty Jo" wrote in message
...

"Suzy O" wrote in message
...
Trees never wreak havoc on sewers. The piping has to be compromised
first
for tree roots to get in -- roots cannot break their way into sewers.
More
likely the dude wants the space for a parking space and is using the
sewer/root argument to back up his claim, IMHO and just surmising.

Suzy O



In older houses (like mine) many sewers are plumbed with 2ft clay tiles,
one
end has a bell shape and the male end fits in the bell.....tree roots can
readily penetrate this type of drain line.....luckily the neighbors
Popular
tree decided to croak and no longer plugs my line annually although said
tree just dropped a rather large branch on another neighbors roof (Big
tree)......the sweet lady whom originally planted the trees (since
deceased)
in 1966 had not idea such little twigs could get so big....Rod