What is the maximun prison sentence for gbh section 18?

I think it's 1-2 years... Not sure... Depens on the amount.

Actually, the amount is irrelevant in California. Because it is considered the 'date rape' drug, even a few ounces can lead to the same sentence as a few gallons. Of course, 'intent to sell' is a harsher conviction. In most states, simple possession can range from 1 to 5 years in jail and up to $100,000 in fines.