Surprisingly, no. The vast use of water is for water-intensive crops and for industrial and commercial uses that tend not to be in cities per se.
Should people in cities use less water to maintain lawns of non-native plants that they water during the day when the water evaporates? Sure.
Will doing so radically alter the water usage? No.
The primary drivers are the water-intensive crops (largest) and the commercial and industrial uses of water (second largest).
When doing triage, look at the biggest sources, not the smallest. If you don't fix the hole in their heart, they can't pump enough blood even if you patch the small leaks in the limbs.
Blaming others (e.g. LA vs farmers) is easy and fun, but it frequently accomplishes nothing.