The Bills mods keeps household data in whichever save you use to play with it. This data doesn't affect your save if the mod isn't present. It is just a placeholder for when you decide to update your game but the mod also needs to be updated. While you wait, you can play your game as normal without the mod and then when you add in the updated Bills, that data is right there and ready to be used.
If you should decide to remove this data completely, before removing the mod complete the following steps:
Open your cheat console with Control + Shift + C and type in "snbb.uninstall"
You will get the below pop-up and say "Yes..." to continue on with the process. If you change your mind at this time, just say "No."
To finish the uninstall process, save and exit the game/save. If you have more saves that you used SNB - Bills, you will need to repeat this process to completely remove Bills data from your ENTIRE game.
Done! The next time you play, there should be no evidence of Bills left.