The word wastewaters is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 17
Highest Scoring Words With Friends™ Plays In The Letters wastewaters
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Seven Letter Word Alert: (22 words)
aerates, estates, reseats, restate, retaste, retests, searats, seastar, seaters, setters, staters, stratas, streets, swatter, sweater, tasters, teasers, teaware, tersest, testers, wasters, wetters