Location: Miami, Florida
Property location: About two miles from Atlantic Ocean, soil is sandy.
Property is single story, on monolithic concrete slab 8" thick. Via video
inspection determine line is broken about 5 feet inside from an exterior
wall probably directly under a cabinet in the kitchen, with no replacement
tiles available. The line is broken near an elbow so using a resin liner
solution is out. Had two drain company came out and both recommend tunnel
under house.

Roto-Rooter estimated $1800 excavation + $900 pipe repair. The $1800
excavation cost is based on a $180 per foot basis. Since the location is
around 5 feet in, they figured 4 feet deep, 5 feet in, and an extra foot for
manuever will add to 10 feet. However, if there is a footing to cause them
to dig deeper than originally thought (I am pretty sure there is), or they
hit the water table (yes they probably will...) or the location is not
pinned down and they have to dig further to find the break (and that may
happen too...), it will be however long they dig times $180. So I figure
conservative estimate will be to figure 20 feet, which will mean $3600 +
$900 = $4500. I asked them how they will back fill and they told me they
will put the original dirt back in and it should be OK. The digging will be
done manually. They did not say whether there will be any permit fee or
whether they will get a permit or not.

The AAA Rapid Rooter came by, and their estimate is totally different. They
told me their charge is $7500 minimum. Minimum meaning they don't run into
complications. I asked them what they included, and they told me it
included using a "vaccon" truck to dig the tunnel (not manual digging), they
add water and literally "suck" the sand out and form the tunnel, the actual
pipe repair, permit fee, engineer to come out to see the soil sample is
suitable for excavation of this nature, backfill with a truck shooting wet
sand (may mix some cement in) into the tunnel. The total will be $7500.
They will not provide an itemized breakdown since some clients used their
estimate to get insurance money but never do the job.

So drastically different approach. Machine digging with water versus manual
digging. Manual backfill with excavated dirt versus shooting compacted
sand. One job is about twice as the other.

Any ides which one is more "safe"? I have the feeling manual digging is
less damaging and involve less disturbance to the soil and can keep the
tunnel size smallest, is this right? But backfilling with the original dirt
concerns me. Not sure how you can backfill the void that is above the
footing back without some sort of pressurized method. Both are reputable
companies.

I am thinking one possibility would be to use Roto-Rooter to do the repair,
and see if they will come down on the price if I ask them NOT to back fill.
I will back fill myself and see if I can find a subcontractor that will do
the wet sand shooting back fill. But will this work? They can't pull the
permit if I am going to do part of the work myself?

Any advise?

MC