Private wells throughout central Florida have arsenic levels above the maximum contaminant level (MCL) of 10 µg/L. We conducted a biomonitoring project of residents with wells above the MCL (higher risk) and below 8 µg/L (lower risk) to determine the relative importance of dietary and water sources of arsenic. Urinary arsenic did not differ by risk status, though higher-risk residents were more likely to use bottled or filtered well water as their primary source for drinking, cooking, and brushing teeth. Higher income, home ownership, and more servings of fish, seafood, white rice, and wine were associated with higher urinary arsenic levels. Similar relationships were seen when excluding individuals who consumed fish or seafood within 3 days of sampling. Provision of filters and bottled water to higher-risk households provided protection from arsenic exposure through well water. Diet and lifestyle factors, however, contributed to higher urinary arsenic levels among participants, regardless of household risk status.