Yesterday we had to free the approx 100 foot main sewer pipe out to
the connection to the municipal sewer in the street. Our connecting
pipe is four inch inside diameter plastic.
It is about 8 feet deep; the pipe exiting below the footing of our
concrete basement wall which is 8 foot high (plus a six inch footing).
The concrete wall only 'shows' above ground by some six to eight
inches. Our basement is therefore almost completely 'in ground'.
There appeared to be two blockages; one a few feet out from the house,
possibly at the location of an underground 45 degree horizontal bend
in the pipe. The other almost 100 feet out to the main sewer. This
second blockage may have been an accumulation of waste due to the
first blockage possibly only allowing a trickle to escape. The problem
however appeared to occur rather suddenly!
The vigorous application of a 100 foot flat steel 'snake' was
successful in freeing things up.
This is only the second blockage we have had in some 39 years. The
other one being some 20 years ago and due to an accumulation of too
much fat from cooking and draining numerous Christmas turkeys for the
local parish etc.!
1) We have a lot of trees. Is it likely that roots could go that deep
and get into the sealed pipe? We had another problem with tree roots
in a land drain, last year. but that drain was only about 1.5 feet
deep and some 100 feet distant from this one.
2) Would the frequent application of coarse salt to the sewage pipe
help to kill or discourage he growth of tree roots; if that is the
cause? The municipal sewer outfall in this instance, after minimal
treatment, is directly into the salt water ocean.
Any comments/advice much appreciated
It is unlikely in the extreme that a plastic pipe could deteriorate or
crack, thereby permitting the incursion of tree roots. It's possible, I
guess, for a connection to come loose, but again, that would be very rare.
Tree roots go where the water is. Remember, a tree has as much biological
material BELOW ground as it does above.
Salt does discourage roots.
I think you have a one-off situation and it's just one of those things.
Don't fret about a one-time event.
Are you sure that pipe is plastic. In 1970 plastic was only just coming into
use. I know because I built my house that year and plastic pipe had just
started to be used for inside piping. There was some plastic pipe used for
sewer lines but did not have glued joints, they used slip joints that was
sealed with some caulk type material, tree roots could penetrate if it was
not done correctly or has failed. Also there was commonly used a
asphalt/cellulose pipe that went under many names such as NoCoRode. The
joints were hammered together and frequently failed or the pipe crushed over
the years allowing roots in.
If it happens again have the pipe scoped to see if and where problems are.
The problem with scoping a pipe is cost. The last two plumbers quoted me
US$1500 to US$1800. I thought they were joking at first. They weren't.
Then there's the cost of digging the dang thing up. I'm sure there are some
that could wield a shovel at the incline and depth necessary for a sewer
excavation or sit behind a Catapillar without fear... Either of those would
be issues for me. My city's streets-and-sewers department is willing to do
both (for a cost) but as long as I can rotorooter the line, I'll pass on it.
I like your plan.
You might keep an eye peeled on Ebay for a sewer camera. I just looked -
there are several in the $600-700 range. And, of course, they can be re-sold
after you complete your inspection.
Thank ya kindly, sir. I'd still allow someone with more experience wielding
shovel or Catapillar handle the dirt. I'm sure I could _probably_ do the
camera work but the learning curve might be just as extreme. I don't know;
I've never used one. The "super" snake was quite challenging without a
Journeyman Plumber available.
When I had my city's streets-and-sewers guys out, they warned me against
DIY'er videos. It would seem our City's manager is a vampire in his
afterlife. Anything that the citizens can pay for, he's sure to ferret out
and put a "rule" into place.
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