Nope nope.
It's probable cause. Essentially it means you have some witness or hard evidence that gets you beyond a hunch. That's it. It's super low. A mandatory reporter, a former friend, not intentionally informing, and a messed up stream gets you there.
In the CPS case it was preponderance of the evidence. Hence why the Judge didn't buy Nick's genius strategy of "Well, if I don't give permission to see my positive hair sample and I say I can't say what all those drugs were doing in my bedroom in case I somehow compromise my possession case, these idiots need to return my kids, cos that can't prove anything!"
Unsurprisingly the Judge didn't turn off his brain and decided it was more likely than not they were using and went with CPS and Guardian to pee clean.