There is such a thing as too much water. It's called water intoxication, or hyponatremia. This phenomenon occurs when a person drinks an excessive amount of water in a short period of time, washing away the body's electrolytes & causing a sodium imbalance in the body. In extreme cases, this imbalance can lead to swelling in the brain and can prove fatal if the electrolytes are not brought back into balance.
It's difficult to judge the amount of water that could cause intoxication because it really depends on a number of factors. However, most sources say that one should not exceed 34 ounces of water in one hour's time, even when participating in strenuous exercise. That's why the hourly goal for the water week project is a mere 8 ounces per hour.
Don't let this information scare you away from regular hydration. All in all, your body does a pretty good job of letting you know when enough is enough. For example, yesterday while trying to finish off a bottle of water quickly in order to re-fill my travel canister before leaving the house, I received some very clear & distinct signals to slow down on the hydration. I had only had a maximum of 24 ounces within an hour's time, but my sloshy tummy, tense abdomen, & overall feeling of queasiness told me that rushing that last few ounces was not the best idea. The point is, while 8 ounces per hour should be perfectly fine for regular consumption, always listen to your body and never force anything that feels "wrong."
Since my slight over-indulgence, I've simply slowed down my water pacing to a precise 8 ounces per hour & I now make sure to sip slowly more often than I chug.
Listen to your body & always practice safe hydration. ;)