Yes, WETTERS is a Scrabble word!

Letter values in Scrabble US: W 4, E 1, T 1, T 1, E 1, R 1, S 1.

Is it a valid word?

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

a chemical agent capable of reducing the surface tension of a liquid in which it is dissolved
a workman who wets the work in a manufacturing process
someone suffering from enuresis; someone who urinates while asleep in bed

Also: wetting agent, surface-active agent, bed wetter.