Yes, WASHBOWL is a Scrabble word!

Letter values in Scrabble US: W 4, A 1, S 1, H 4, B 3, O 1, W 4, L 1.

Is it a valid word?

WASHBOWL is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a bathroom sink that is permanently installed and connected to a water supply and drainpipe; where you can wash your hands and face
a basin for washing the hands (`wash-hand basin' is a British expression)

Also: wash-hand basin.

Not playable in Scrabble US: HANDBASIN.