I have a gas smell when I'm idling at a light or after I stop the car and turn it off. Didn't notice it much when we were parking it outside. when I parked it in the garage really noticed it. What are the causes of this?

First - check the fuel tank gas cap- is it snapping on okay? - sealing properly-- also check under hood for any obvious liquid leaks- puddles, drips- gas under hood is not good- and needs fixed pronto......do you have any service engine lights- like for the famous gas cap code?