Insurance agents and brokers assisting flood insurance policyholders may find a stark difference in premiums depending on income levels in the communities where they live. According to a report released this week from the University of Massachusetts Dartmouth, wealthier communities boasting higher-value properties along the coastline typically pay hundreds of dollars less in premiums than homeowners in low income communities. In fact, under the National Flood Insurance Program, blue-collar Fairhaven, Massachusetts pays an average $1,800 a year for a policy -nearly a third-more than Edgartown, Massachusetts homeowners, who pay about $1,400 for the same policy.