Water, Safety, and Clean Air eh? Not Health Care? (are you planning to fly back to Canada for that?)
All of SoCal has more or less the same water (brought in from NorCal, the Sierras, or the Colorado river).
Many neighborhoods throughout SoCal are relatively safe. Many others are not. Local RE prices will reflect this.
SoCal is not exactly the best place for clean air. I lived in San Gabriel Valley for more than 25 years (from late 60s to mid 90s). Was like smoking a pack a day. You need to stay close to the coast for “cleaner” air. This means more $$$, but sounds like school district doesn’t matter, which will give you better selection. IMO, SoCal coastal prices are likely to drop significantly over the next three years, so I would stay in (Canadian) cash and rent for a season or two before you make any purchase decision. That way, you can try living in a few different areas before deciding if you really want to spend half your retirement in SoCal.
