A couple of friends of mine who are lifeguards here, in one of California's more expensive counties, make squat. Regardless of their "rank". They compensate by bartending or teaching surfing lessons, etc.
If lifeguards in Newport Beach find their cost of living there to require more pay, they should find night-time employment, or move.
Newport Beach doesn't require much "lifeguarding" anyways.. so some overweight tourist twists her ankle in the surf? If she doesn't keel over, she'll hobble out to safety just fine on her own. Hardly merits that pay hike.