Bounce house companies say they clean and disinfect, but how good of a job do they really do? And how clean are those bounce houses before and after your kids play in them?

The step into the bounce house comes in at 220, about nine times the limit. And that’s just after the employee setting up the toy had wiped it down.

Inside the bounce house, we get filth levels of 33, just over the limit but much cleaner than the step.

Then we let kids loose on the bounce house. After they play for an hour, we tested it again and the step came in at 778. Inside the house, levels rose to 225, another big jump.

That’s from only four or five kids playing in the toy.

Dr. Andrew Carroll says those levels aren’t a surprise though.

"It's kid feet. It's kids handling food. It's kids touching one another and rolling all over one another, picking their nose, dabbing their eye, dirty diapers,” Carroll said.

But what happens if it’s not a small party and a lot of kids are playing in the bounce house? The numbers go up, way up.

An hour after letting kids play, we find an average filth level of 2,087 inside the house and 3,931 on the step – one of the highest tests we’ve ever seen.

For reference, that’s 131 times the healthy limit.

While these are supposed to be cleaned for each use, Carroll said bounce houses are nearly impossible to fully sanitize.

"The bacteria gets trapped in between the surfaces and just sits there. Unless they're blowing up that castle and just thoroughly scrubbing it in between each episode, I just don't see it being thoroughly cleaned," he said.

So you probably shouldn't expect a bounce house to be clean and sanitized next time you let you child play in one.