When it comes to drawing the line between what is and isn’t appropriate to ask a job candidate, the parameters aren’t always clear, according to a new CareerBuilder survey released today. The survey found 20% of hiring managers indicated they have asked a question in a job interview only to find out later it was illegal to ask.

“It’s important for both interviewer and interviewee to understand what employers do and don’t have a legal right to ask in a job interview – for both parties’ protection,” said Rosemary Haefner, chief human resources officer at CareerBuilder. “Though their intentions may be harmless, hiring managers could unknowingly be putting themselves at risk for legal action, as a job candidate could argue that certain questions were used to discriminate against him or her.”

The following questions are illegal for hiring managers to ask; yet, when asked if they knew if these questions were illegal, at least one third of employers indicated they didn’t know:

• What is your religious affiliation?
• Are you pregnant?
• What is your political affiliation?
• What is your race, color or ethnicity?
• How old are you?
• Are you disabled?
• Are you married? 
• Do you have children or plan to?
• Are you in debt?
• Do you social drink or smoke?

The survey was conducted by Harris Poll on behalf of CareerBuilder among 2,192 hiring managers and human resources professionals. The survey was conducted from Nov. 4 to Dec. 2, 2014.