You *can* say it is incorrect, in most cases.
In fact, water overconsumption can easily lead to hyponatremia. It would be more correct to say "Steady, adequate freshwater intake throughout the course of the day curbs the likelihood of hypernatremia, a form of dehydration. Note that in a balanced diet, a significant portion of the body's water and sodium requirements come from food. Note that fruit juices, or a combination of fresh fruit and freshwater, meets the body's needs for water and sodium near-optimally. Note that isotonia, the excessive loss of body fluid, such as through diarrhea or vomiting, is a type of dehydration best treated by electrolyte solutions like Gatorade or Pedialyte, or parenterally via a 0.9% saline drip in severe cases. Note that hypovolemia, the excessive loss of body fluid typically through excessive bleeding, should be treated with medical care. Also note that rapid intake of freshwater over a short period of time is not as effective as a sustained intake throughout the day, as sudden rises in body water content are simply filtered by the kidneys in healthy individuals. Repeating this rapid intake behavior excessively can lead to hyponatremia, a form of dehydration, or, in more serious cases, hypovolemia, a condition related to dehydration that requires medical attention. In individuals with compromised excretory function, rapid water intake may lead to severe hyponatremia, a form of dehydration that requires medical attention, or a more severe condition of hypervolemia characterized by a swelling of the limbs known as peripheral edema or more severe and life-threatening complications, particularly in individuals in poor health or with poor diets or diets lacking in protein. Greatly excessive and sustained intake of freshwater combined with excessive perspiration may continue past hyponatremia to the point of water intoxication, a medical crisis that may cause brain damage or death."
But, I guess that doesn't have quite the same ring to it, eh? ;) "brain damage or death" is probably one of the potential side effects that bottled-water manufacturers want to list on their products... heh.
Note, IANAMP (==medical professional); I just study medicine (and mostly neuropathy and neurosurgery, at that) as a hobby, so please feel free to correct the above.