With one dedicated chemist it wouldn't be difficult to accomplish this. The security at water complexes is actually really lax. The amount of LSD you'd need to synthesize to poison a small town would be doable over time. You just need enough precursor.

The CIA did create the hippie movement.

Damn my mom told me this about the CIA over 15 years ago! There were always rumors she said it as fact. Now it is officially confirmed. I am gonna call her and let her know! Thank you! Take care and be easy!