There is very little in the article about how the technology actually works, other than some vague indications it relies on carbon nanotubes, which so far haven

There is very little in the article about how the technology actually works, other than some vague indications it relies on carbon nanotubes, which so far haven't really been useful for anything, outside of academic curiosities. Testing your water is actually easy, you collect some and send it to an analytical lab that uses standard processes and understands possible interference. edit: the video shows a bit more, the nanotubes appear to have been chemically treated with compounds that show an affinity for lead, not much information beyond that. This seems like quite a feat to accomplish at home. My experience in grad school with high school students working in our lab was that you needed access to the university facilities to do well at these competitions.