How much of the ocean would be consumed if everybody drank desalinated water?

Well, we are supposed to drink about 3 liters(0.8 gallons) of water a day, and the world population is estimated 7.53 Billion . That 23.49 Billion liters(6.2 billion gallons) consumed per day. The ocean is  1.335x10^21 liters. Assuming that you don't put the water back in the ocean it would take 5.7 billion days or 15.6 million years.

Assuming no math errors there's your answer.

If we are going by assumption that no one would ever excrete urine, then it would take a VERY long time, roughly 200 million years, assuming you drink 8 cups of water a day at 8 fl.oz. for 64 fl. oz. total. Multiply that by the amount of people in the world, 7.6 billion (roughly) and you would get 486.4 billion fl. oz. each day. The oceans are MASSIVE and EXCEPTIONALLY deep. All of Earths mountain ranges could fit inside the oceans just for perceptive. The oceans contain roughly 33,375,000,000,000,000,000 GALLONS of water. Take that number and divide it by the amount drank per day, you get roughly 686728395 DAYS of water for everyone in the world to drink. It would take many, MANY years for that supply to run out, about 200 million years (188 to be exact). If we are going to go the way that nature works, none! The amount of liquid we would put in ourselves would be equal to the amount we put out. So it would stay the same forever!

About 17 of the ocean water would be consumed

In a steady state sense, none. the water would all be returned to the ocean with time.

But if you want to do a rough ballpark estimate, let's do one. Assume every person drinks 10 liters per day (way more than true but still same order of magnitude as 5 or 12 or 8, and an easy number to use). there are 7 billion people (a little more actually), so that means that we drink about 70 billion liters per day.

1000 liters in a cubic meter, so 70 million cubic meters. That is less than a cubic km (there are one billion (10^9) cubic meters in a cubic km), and there are 1.3 billion cubic kilometers in the ocean, so basically, about 50 parts per trillion of the ocean every day. 100 billion days worth of water, as a ballpark estimate. Play with the numbers a bit and you will get a different answer in detail, but it will still be on the order of billions of days of use, many millions of years.

Basically, a lot more water is lost to air by evaporation every day than we would use for drinking via desalination. the ocean would not change in any important way.

just a very very few part of it ....

Zero. Nature is the perfect recycler.

The carbon cycle, the water cycle and many other cycles.

Any water consumed either is evaporated directly, used in creating body tissues, or becomes waste.

The waste is treated and either returned to rivers and ultimately to the sea, or it is used to water plants which evaporate the water and it becomes rain. Which also gets back to the sea.

There is nothing that YOU can do with water that takes it away from the cycle.

Only icecaps take water out of the system. And they come and go over time intervals of tens of thousands to hundreds of thousands of years.

Which is very short relative to geological time frames.

None. The water cycle (evaporation/precipitation/drainage) coupled with human bodily functions (sweat, respiration and urination) would see it returned to the ocean eventually. There would be a time lag.

None, the Earth's physical does not make the water, the Atmosphere does it would be replenished.

very little much

none , you put back as much as you use