I just put a back flow preventer on my water meter.

The meter is in a pit outside the house. I would estimate the meter/back
flow preventer is 150 ft away from the water heater in the basement.

I have been told that due to the distance between the meter/back flow
preventer and the water heater that I do not need to put an expansion tank
on the water heater.

Does anyone have experience with back flow preventers located 150 ft from
the water heater? Is it necessary to install an expansion tank in such a
situation?

Thanks,
rac