Daughter's in 3rd grade; has 20 minutes of reading a night and about 40 minutes combined for writing and math. She's in advanced math, FWIW. There is sometimes extra time if she needs to study for a test or is working on something like learning the multiplication tables.
Seems like a reasonable load for a kid her age and she is doing very well. As far as curriculum, she is way ahead of what I was being "learned" when I was 9.