How much water can you consume in one day?

depends on how much sex you have in one day.

Great question!

There is a school of thought that you only need to drink a certain amount based upon your weight. I use a Hydration Coach, a "smart water bottle," that makes this calculation for me and helps me stay on track. I can adjust the calculation by subtracting fluids I don't take via the bottle, such as coffee, tea or juice. Their calculator is here.

I may not be a "high performing athlete," but I am a marathoner/athlete approaching age 60. As a coach, I've been teaching our training program's "rule" that our sports nutritionist follows: your body can only absorb about 4-6 ounces every 30 minutes. That would put you at about 8 ozs (or, 1 glass) of fluid per hour, totaling 64 ozs in a typical 8 hour day, as Mayo Clinic suggests.

The danger of hyponatremia can be very real; but, as Alison pointed out, if you're not at a high athletic activity level, this danger may not apply to you. The woman you may be referring to, and I'm just guessing here, is the Chicago marathoner who over-hydrated with plain water and did not ingest any electrolytes to replace the essential minerals lost during such an event - potassium, sodium and magnesium.

The bottom line is to drink clear water as much as possible and take in fluids before you feel thirsty. Our bodies are a big fluid bag and we need to maintain proper hydration to keep our internal works, skin, etc. healthy.

According to the Mayo Clinic, it is possible to drink too much water, leading to severely low sodium levels in the body, called Hyponatremia.
http://www.mayoclinic.com/health/hyponatremia/DS00974

For the vast majority of us who are not high-performing athletes, and do not have an underlying medical condition that may influence our sodium levels dropping...this is very uncommon in people just casually "drinking too much water".

How much water to drink, depends on if you are trying to maintain proper hydration (before you feel thirsty), or to replace lost fluids. The Mayo Clinic recommends 6 cups of water to 8 glasses of 8 oz. each of water (64 ounces, total), depending on your activity level, or if you are trying to prevent dehydration.