Where should I place water treatment plants in Simcity 4?
Solution 1:
I'm 90% sure that the correct answer is anywhere, however, keep in mind they have a rather significant NIMBY issue, so keep them away from sensitive zones.
Solution 2:
I've always found that slapping them down in industrial zones helps to alleviate the NIMBY issues they generate. That and by any rivers or seas seems to work decently (I dont' play landlocked maps due to the desire for street variety/love of bridges)