I have a single story home with a monolithic concrete slab and my sewer line
below the slab is in need of repair due to a crack, sand piles in as laundry
water is discharged through the line at a rapid rate and caused partial
blockage. The problem has been confirmed by a video of the line.

I called the insurance company and the adjuster called back. I explained
the problem to them and was told nothing is covered unless there is actual
damage to the property. For example, if the pipe burst caused the carpet to
be ruined, they will cover it. If it caused walls to be moist they will
cover it. I told the adjuster over the phone that I know the pipe is
seeping water and that could be flooding the slab from below and eventually
popping my tiles out it's just a matter of time. I also told them the sand
is being drawn in through the crack and is piling up downstream, this could
cause an erosion of soil below my slab and my house can sink because of it
(may be a little exaggerated). They said they will send someone out to see.
Does anyone has experience on this that can advise whether there is any way
this can be covered? Is it really how you technically state the problem?
Any comments will be appreciated.
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Your adjuster is correct. In standard policies, nothing is covered
unless actual damage occurs. If damage is imminent, as you claimed,
then the adjuster is doing the right thing by sending out someone to
see. If the inspector determines there is damage imminent, and it's
cheaper for the insurance company to pay for the repair now, rather
than wait for a larger claim later, you'll probably be covered for the
repair. Not all insurance companies will operate in that logical a
manner though, so YMMV.