It's good that you are drinking when riding in the heat.
What size are your water bottles. I's seen some as small as 16 oz and others, like the Zefal Magnum, which hold 32+ ounces. Of course the larger bottles sometimes can cause fit problems as they are taller. Often they can't fit on the seat tube on smaller or compact frames.
I agree that you should consider using something like NUUN tablets if drinking that amount. You can get sick from just plain water.
For your 34 mile ride (which you will do) you might consider using some diluted sports drink like Gatorade. About 2 hours of riding is when you need some carbs and electrolytes especially if you are sweating a lot.
Are you hydrated before your rides? You might be starting off behind the power curve on fluids if you are dehydrated before riding.
There is one other thing that I really hate to bring up. But here goes: excessive thirst is a symptom of diabetes. Have you been check for that medical condition recently?
Last edited by JerrySTL; 07-27-15 at 11:59 AM.