Yes there is a state or local agency you can contact, Department of Health is either (Depending on where you are) THE agency, or can point you to it.
I clearly will not argue with the professional as to what the problem is.. Just clean/replace filters often is all I can advise. There is a cure for the problem (At least I think there is) but you can not do it. Because it is not your problem.
At most of the parks I visit reqular water quality monitoring is the law. The Health dept will shut 'em down if something like that happens.
