The SOAP-based We Know a Place API incorporates their California senior housing directory into your application so people can search. Their services are free and they have connections to a wide range of housing types: assisted living, Alzheimers care, elder care, home care, residential care homes, retirement communities, hospice, and nursing homes.
We Know a Place is a referral service that, according to its blog, addresses the California aspect of a massive need,
...this year, about 9 million people over the age of 65 need long-term care. By 2015, over 10,000,000 seniors in Americans need long-term care. Many seniors are taken care of at home by loved ones and friends that are sole caregivers. This accounts for seventy percent of the elderly. Some recent research done by the U.S. Dept. of Wellness and Human Services said that people who reach sixty-five most likely have a 40 percent of a chance of entering a nursing home and nearly ten percent of the individuals who enter a nursing home may remain there five plus years.
The reasons for a referral service become clear to anyone who hasn't encountered these issues already. As one blog post spells out, there are a massive array of different types of housing, as well as so many facilities that cater to each type.