The treatment standards for rainwater typically come from local health departments - if there are national standards I've not been able to find them. For indoor non-potable use typically the rainwater is filtered prior to being put into the distribution system, which is often must be labeled as Non-Potable Rainwater. Many jurisdictions require signs "Non-potable - Do not drink"; I've seen these hung in the bathrooms above each toilet (regulations going too far, if you ask me). Disinfection is likely to be a requirement for indoor uses.
For outdoor irrigation, filtration is desirable to protect emitter heads from clogging. I've had jurisdictions require disinfection, although some don't require it for drip irrigation, only for spray irrigation.