"Mom, I need a drink of water" repeated several times a day x # of children, doubled in summer.
One of the best things I ever did was put one of these things on my counter.
It's high enough that my youngest cannot use it (1 1/2) but perfect for the other two (3&5). Place an absorbent rug or towel on floor for little spills.
Next make cups accessible so they can do it on their own. so the next best thing I did was toss (literally) all the kid's plastic dishes and cups in a large bottom drawer where they can reach it.
Not only can they get thier own drinks of water, but help set the table and empty the dishwasher. Oh it is pure bliss.