Question: What is the difference between "much" and "many"?
Quick Answer: "Much" is used for an amount of something and "many" is used for individual items that can be counted up.
Help! There is too much water in the bath tub and it's starting to overflow!
How much water should you drink on a hot day?
How much water is in the ocean?
What if the waiter at a restaurant asks how many waters we want for the table? Doesn't that make sense? Yes, but the waiter is using the word "waters" to mean "glasses of water", which are, of course, individual items being counted up. This brings up another important trick: if you can add "s" to a word to make it plural, you can use "many" to describe it. (You can also use "many" with other kinds of plurals, of course, such as "children", "women", and "deer"...)
I drank too many glasses of water before the long car ride.
This summer we grew too many zucchinis.
Many deer live in these woods.
Now you know. To double check yourself, ask whether you can make the word plural. If so, you can have "many" of that item. If not, you can have "much" of it.