( ( Grey water ) ( ( can ( be ( used ( for ( flushing ( the toilets ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Grey) (NN water)) (VP (MD can) (VP (VB be) (VP (VBN used) (PP (IN for) (S (VP (VBG flushing) (NP (DT the) (NNS toilets)))))))) (. .)))
Grey water can be used for flushing the toilets.
(ROOT (S (NP (NP (DT The) (NN action)) (PP (IN of) (S (VP (VBG flushing) (NP (DT the) (NN toilet))))) (, ,) (VP (VBN performed) (NP (JJ multiple) (NNS times)) (ADVP (RB daily))) (, ,)) (VP (VBZ is) (NP (NP (DT the) (ADJP (JJ single) (JJS biggest)) (NN use)) (PP (IN of) (NP (NP (NN water)) (PP (IN in) (NP (DT the) (NN home))))))) (. .)))