7.86% of the population for whom poverty status is determined in Castalia, IA (11 out of 140 people) live below the poverty line, a number that is lower than the national average of 12.5%. The largest demographic living in poverty are Females 55 - 64, followed by Males 45 - 54 and then Females 25 - 34.

The most common racial or ethnic group living below the poverty line in Castalia, IA is White, followed by Black and Native American.

The Census Bureau uses a set of money income thresholds that vary by family size and composition to determine who classifies as impoverished. If a family's total income is less than the family's threshold than that family and every individual in it is considered to be living in poverty.