Cost-effective landscape recommendation (high water bill!)

[Edita D.]

Hey guys!
For our 4-plex the water/sewer bill runs about 250$ (per 60 days), however it's been 400$ lately (we think our new tenant is using more water to keep a nice landscape in front of his building).
We want to evaluate if it would be more-cost efficient to replace the grass with something else that does not require constant watering. I was thinking mostly rocks with some succulents (native for San Diego area!).

What would you say? Any other ideas? In your experience, how much would the project run for (per sq ft).
Thank you!
Edita