I have a third-grader and a kindergartner in NC. My kindergartner usually has half an hour to an hour of homework a night. My third grader usually has 1-2 hours of homework, but some days he has homework from the time he gets home until bedtime.
In many cases, the work he's doing is not adding or reinforcing anything. He spells like a champ. Writing the same spelling word 30 times in 5 different ways does not help him become better at it. He's good at math, but that doesn't stop the worksheets with endless math problems. Sometimes those worksheets do a great job reinforcing a concept, but sometimes they're just repetitive torture.
And now we have a new thing where third graders can't progress to fourth grade if they don't pass an end-of-year reading test. I have mixed feelings about the overall concept, but in execution it just means more work for my son. And also, he could have passed the test on the first day of third grade, according to his beginning of year reading assessment. But does that save him from all these reading comprehension worksheets, or the weekly quizzes? Nope.
There are some people here saying that kids need homework so that they'll be ready for college. I think it's foolish to say a third-grader needs multiple hours of homework a night in order to prepare him for something he might do in nine years.