We provided preliminary data on levels of nicotine deposited in houses of e-cigarette users. Nicotine was found in only half of the e-cigarette smoking homes. The levels of nicotine in e-cigarettes users’ homes were almost 200 times lower than the levels detected in tobacco smokers homes. These results indicate that using e-cigarettes indoors results in much lower exposure to nicotine residues on surfaces compared to smoking tobacco cigarettes.