Hyponatremia is only a concern if you've just ran a marathon or something - and then you consume a lot of water in a short period of time.
You don't have to worry about this if you consume a lot of water throughout the day (under the assumption that you aren't engaging in hardcore endurance activities and then chugging huge quantities of water)....
I drink between one and two gallons of water daily....I don't really keep track - but I ALWAYS seem to have a 30 ouncer of water in my hands.