spill over
1. Of a liquid, to spill by flowing out of a container or over some barrier. You're going to need a bigger pot, or else that soup will spill over. The floodwaters spilled over the levee.
2. To go beyond the borders or parameters of something and into something else, especially due to growing in size or scope. It's hard to contain violence to just one neighborhood, you know. It's only a matter of time until it spills over into our part of town too.
spill over
1. [for a container] to overflow. I hope your bucket of water doesn't spill over. The milk glass spilled over because it was filled too full.
2. [for the contents of a container] to overflow. The bucket is too full. I don't know why the water doesn't spill over. The milk spilled over because you overfilled the glass.