You might want to stick a 'solely' in there, because it's plain not true that the majority of beef production does not use grazing. Most beef production raises on grass and 'finishes' on grain, and there are lots of different grades. Some beef is raised on little but grain. It varies heavily on location and climate.

My main point stands. If you want to dramatically reduce your impact on water use, consume less meat.

And wear less cotton, eat less wheat, sugar, fruits and rice.

You are arguing for the sake of arguing, and making bad arguments as a result. If you eat vegetables instead of beef you will save a lot of water. You will get the same amount of food, with far less water use.