I usually do all my yard myself but after last yrs drought i decided to get it done professionally.
I received the first treatment of pre/post emergent and they advised me to water it about an 1/2 inch or so in the next week.
I wasnt aware that spray form needed to be watered in like granual form.
Any thoughts or opinions?

It needs to be watered in. Just follow the instructions they give you.

When the liquid is sprayed, it tends to sit on top of the dead grass, leaves, and other surface material, but it needs to get closer to and beneath the surface into the soil and do its weed preventing thing....