What do I need to know about state withholding tax?
Every employer who maintains an office or transacts business in Iowa and who is required to withhold federal income tax on any compensation paid to employees for services performed in Iowa is required to withhold Iowa individual income tax from that compensation.
Nonresidents must file an Iowa income tax return (IA 1040) if their net income from Iowa sources (line 26 of the IA 126) is $1,000 or more.
New employers are required to register for a withholding account.