It is possible to owe the state of Iowa taxes even with a basic tax return, single, and 0 dependents. This may be due to insufficient deductions or higher income pushing you into a higher tax bracket. For a single filer in Iowa, you are required to pay income tax if your income is more than $9,000, See Iowa Tax Tables here.
Being single, you may not have enough deductions or credits to offset your income. Additionally, if you have interest, dividends, or an extra job, it might increase your income.
Here are some links that might help: