You can clean PCBs in water if you must, as long as a few things are observed...

1 - no EM devices (switches, relays, dip switches) or coils on the PCB
2 - another water removal agent used as soon as possible - Isopropyl or Methylated spirits rinse
3 - board then allowed to dry thoroughly in a warm area.

But again, I would personally go: shellite (only if nasty-dirty), Metho/Iso, then drying. Soap and a hose ... well ...  suppose it works for now... but long term... sheesh!

Cheers
Jacob