Replacing a solenoid valve under water?

Question

I have a Rainbird valve right before the backflow preventer. Not sure why they did it this way. Anyway, it is leaking. I think my solenoid valve needs to be replaced.

Replacing this doesnt seem so difficult. (1) unscrew the solenoid (2) cut the wires (3) screw in new one (4) wire it up. Easy peasy.

Problem is, it is completely under water. If I unscrew this will it get debris into the system? Not sure how to change when under dirty water.

Answer 1

I cleared out the water. It ended up being the relief valve. The contractor I hired to repair a separate problem left the bleed valve open.