The private sector is returning to the risky world of insuring homes against flood damage, offering hope that the paltry percentage of homeowners with flood insurance will rise out of the single digits. The growth is being triggered by federal policies, new technology that lets insurance companies assess a property‘s flood risk and investors who have poured huge amounts of cash into insurance companies, prompting their expansion into new markets. The National Flood Insurance Program continues to dominate the market, though. Private insurers provides less than 5 percent of residential flood policies, according to a recent study.