These days, if your child starts K not knowing all letter sounds, letter names, and numbers, he or she may qualify for remedial services. It's not that K teachers expect entering students to be able to read novels but they expect them to be able to read beginning readers.
This is highly dependent on the SES of the district. In our high-SES district of largely well-educated parents, many (not all) kids are reading somewhat in K. In the neighboring urban one, I think they simply can't expect that as a given. What the families can do for the kids is, on average, different in different places, and the schools have to work with what the kids know coming in.
