It does sound a little different to any water service in a house that I have lived in. I guess if I was a potential tenant I would like to be told about the water system before I filled in my rental application. Would it turn me off wanting the rent the house? Not at all - but if I moved in without explanation I would probably be frustrated and confused. Sounds like they need a hands-on demonstation from you or your DH because your agent is probably confusing them even more.

Good luck.