(a) As used in this section, the following terms shall have the following meanings:

1. (1) “Community” means an inhabited area within a city or county that is comprised of no less than 10 dwellings adjacent or in close proximity to one another.
2. (2) “Disadvantaged unincorporated community” means a fringe, island, or legacy community in which the median household income is 80 percent or less than the statewide median household income.
3. (3) “Fringe community” means any inhabited and unincorporated territory that is within a city’s sphere of influence.
4. (4) “Island community” means any inhabited and unincorporated territory that is surrounded or substantially surrounded by one or more cities or by one or more cities and a county boundary or the Pacific Ocean.
5. (5) “Legacy community” means a geographically isolated community that is inhabited and has existed for at least 50 years.

(b) On or before the due date for the next adoption of its housing element pursuant to Section 65588, each city or county shall review and update the land use element of its general plan, based on available data, including, but not limited to, the data and analysis developed pursuant to Section 56430, of unincorporated island, fringe, or legacy communities inside or near its boundaries. The updated land use element shall include all of the following:

1. (1) In the case of a city, an identification of each island or fringe community within the city’s sphere of influence that is a disadvantaged unincorporated community. In the case of a county, an identification of each legacy community within the boundaries of the county that is a disadvantaged unincorporated community, but not including any area within the sphere of influence of any city. This identification shall include a description of the community and a map designating its location.
2. (2) For each identified community, an analysis of water, wastewater, stormwater drainage, and structural fire protection needs or deficiencies.
3. (3) An analysis, based on then existing available data, of benefit assessment districts or other financing alternatives that could make the extension of services to identified communities financially feasible.