A city may prohibit or regulate a boarding house with at least three tenants in a low-density residential zone, according to a state Attorney General's opinion. "[P]reserving the residential character of a neighborhood is a legitimate government purpose that may be reasonably achieved by prohibiting commercial enterprises such as operating a boarding house business," Deputy Attorney General Anthony DaVigo wrote. The opinion came at the request of Lompoc City Attorney Sharon Stuart. Lompoc proposed an ordinance prohibiting in an R-1 zone a boarding or rooming house business, which was defined as a single-family home wherein at least three rooms were rented under separate oral or written agreements. An owner, agent or manager may or may not live on the site. In reaching his conclusion, DaVigo cited City of Santa Barbara v. Adamson, (1980) 27 Cal.3d 123, in which the state Supreme Court held that a city may exclude a boarding house from a residential zone. This is because in zoning matters, the term "residential" is distinguishable from "commercial" or "business." Setting the threshold for regulation of boarding houses at three tenants is within the City Council's discretion, DaVigo found. He cited Ewing v. City of Carmel-by-the-Sea, 234 Cal.App.3d, 1579 (see CP&DR Court Cases, November 1991), which upheld a city's authority to regulate short-term rentals. "Line drawing is the essence of zoning," the Sixth District Court of Appeal ruled in Ewing. "[T]he line must be drawn, and the legislature must do it. Absent an arbitrary or unreasonable delineation, it is not the prerogative of the courts to second-guess the legislative decision." Drawing the line at three tenants is not clearly arbitrary or unreasonable, DaVigo wrote. "It is ‘at least debatable' that prohibiting boarding house businesses operated for as few as three boarders in a low-density residential zone is a reasonable exercise of legislative powers," he wrote, citing the standard the U.S. Supreme Court used in Minnesota v. Clover Leaf Creamery Co., (1981) 449 U.S. 456. Furthermore, the ordinance would not deny property owners all commercial use of their property, as they could still rent to one or two tenants, DaVigo concluded. The Attorney General's opinion is No. 01-402 and was published March 19. It can be found at 03 C.D.O.S. 2502 and 2003 DJDAR 3101.