Jim Yanik writes:

I take a craftsman wet/dry vac and have a real long hose.
Then I remove the internal filter. The vac is placed outside turned
on.
I take the hose inside and go to town. Sucks everything outside and
doesnt
clog the vac. Works real well. I got the 20' hose from sears.

but you are pulling dirt into your vac's MOTOR,it's not good for it.
Filters keep the dust from ruining your motor bearings/brush contacts.

That's true for ordinary household vacuums, which run the dirt pickup
air through the motor (after the filter) for cooling. But all of the
shop vacs I've ever looked at have a separate path for motor cooling
air. Motor cooling air comes from the space around the motor via slots.

You really need this change in construction for vacuuming up water. The
filter for water pickup (particularly if it's just a foam sleeve, not a
pleated filter) lets some water through, and you don't want water inside
your motor no matter how briefly. Also, shop vacs normally have a float
valve so when the tank fills up with water the float blocks the impeller
inlet instead of having the vacuum start spewing water out the outlet
port. Once this happens, there's no air flow at all through the tank,
but the motor still needs cooling air. Again, a separate motor cooling
air path solves this problem.

Good central vacs for houses also seem to use separate motor cooling
air, though I've seen one that cooled the motor with the filtered air.
If you throttled the air flow by putting a small nozzle on it, the motor
would overheat and trip a thermal protector after a few minutes on that
particular unit.

Dave