Lead pipes develop a mineral lining that prevents lead from getting in the water. It's when that lining cracks, dissolves, or breaks that it can lead to lead in the water.

So while 10% have lead pipes, it does not mean 10% have lead in their water. It means 10% face a small risk of potentially getting lead in their water. So it is still worth addressing.

100% true, it doesn't mean 10% have lead in their pipes. The question is much better phrased, are your lead pipes safe or not, and for how long? So if you're in that 10%, that seems like a pretty reasonable precaution to seek out alternative sources of drinking water.