COMPTON, Calif. — Alysia Thomas, a stay-at-home mother in this working-class city, tells her children to skip a bath on days when they do not play outside; that holds down the water bill. Lillian Barrera, a housekeeper who travels 25 miles to clean homes in Beverly Hills, serves dinner to her family on paper plates for much the same reason. In the fourth year of a severe drought, conservation is a fine thing, but in this Southern California community, saving water means saving money.

The challenge of California’s drought is starkly different in Cowan Heights, a lush oasis of wealth and comfort 30 miles east of here. That is where Peter L. Himber, a pediatric neurologist, has decided to stop watering the gently sloping hillside that he spent $100,000 to turn into a green California paradise, seeding it with a carpet of rich native grass and installing a sprinkler system fit for a golf course. But that is also where homeowners like John Sears, a retired food-company executive, bristle with defiance at the prospect of mandatory cuts in water use.

“This is a high fire-risk area,” Mr. Sears said. “If we cut back 35 percent and all these homes just let everything go, what’s green will turn brown. Tell me how the fire risk will increase.”