dish·wa·ter 
/ˈdɪʃˌwɑ:tɚ/ noun
/ˈdɪʃˌwɑ:tɚ/ noun [noncount] : water in which dishes have been or are going to be washed
(as) dull as dishwater
US, informal : very boring or dull
▪ The conversation was as dull as dishwater. [=(Brit) as dull as ditchwater]
▪ The conversation was as dull as dishwater. [=(Brit) as dull as ditchwater]
like dishwater
informal : having very little flavor — used to describe soups or drinks ▪ This coffee is like dishwater!
