Freshwater is not abundant in USA. Southern California has to import water from Sierras and as far north as Oregon. Colorado River does not reach the sea. Rio Grande does not reach the sea. Plains states have negative water balance and agriculture only survives by depleting the Ogallala Aquifer. Everything west of the Mississippi-Missouri and south of the Columbia and Platte rivers is at or beyond long term sustainable water consumption. Just add some global warming and see what happens. Read 'Cadillac Desert'.
Now if you said Canada has the largest freshwater supply, I might have agreed.
Go to the grocery store and buy a gallon of water. Imagine that water is what you have to drink, clean yourself, wash your clothes and dishes with. So yes, compared to most of the planet we have it in abundance.
Now the problem we do have is a water management problem. Most of the fresh water is used for agricultural and industrial purposes. We use a lot of water for dumb reasons and then dump it into the ocean.
Now if you said Canada has the largest freshwater supply, I might have agreed.