Habitual total water intake and dimensions of mood in healthy young women: http://www.ncbi.nlm.nih.gov/pubmed/25963107

Effects of changes in water intake on mood of high and low drinkers: http://www.ncbi.nlm.nih.gov/pubmed/24728141

Beverage consumption habits "24/7" among British adults: association with total water intake and energy intake: http://www.ncbi.nlm.nih.gov/pubmed/23305461

Nothing specific to sleep I could find.