It's hot and humid here, and i sweat like a ho in church, so I literally lose 4-5 pounds a day when working.
I fill a 1/2 gallon coleman cooler with reverse osmosis filtered water from my filter, and cut 3 limes in half (10 for a dollar at the produce stand) use a teaspoon and squeeze all the juice and pulp into the water, drop 2 1/2 sections of limes into water, add sugar to taste. (about 3/4 cup for my liking)
Put it in the frig before bed, and its nice and cold when I leave in the morning.
I need a gallon size though, as I drink the 1/2 gallon by midday.
You can cut down to 1 lime, and about a 1/4 cup of sugar for a slightly limey almost sweet drink if you want less sugar.
I find the lime drink is the very best thirst quencher I ever had.
I've tried cold herb teas, lipton tea, red zinger, you name it, I bought a variety pack of flavored tea bags, and tried them all, nothing beats lime or lemon for quenching your thirst with no aftertaste.