Pounding large quantities of water may not be the best or most efficient way to meet the body’s hydration requirements
Electrolytes help retain water and replenish those which get flushed away by the water. Sodium/potassium/magnesium especially need to be replaced because just plain water flushes them out, but we need them for critical biological functions, including proper heart function.
I put 1 tablespoon each of salt, NoSalt salt substitute and Epsom salt in each gallon of water I drink.... that covers sodium, potassium and magnesium. Most over the counter electrolyte replacement waters are expensive or contain sugar which is very bad for most.
Fruits and vegetables have water too + sufficient amounts of vitamins, iron, sugar, calcium, potassium, zinc and many elements our body needs to function well. Eat at least 3-4 types of fruits/vegetables daily. They don't need to be the costliest ones.