Why Does My CPAP Mask Keep Leaking at Night? Common reasons why your CPAP mask is leaking include a poor fit, a damaged or dirty mask, worn-out cushions, your sleeping position, or high air pressure. How to tell your CPAP mask is leaking? How to prevent CPAP mask leaksIdentifying the cause and making necessary changes to your routine can help prevent CPAP mask leaks and increase its lifespan and effectiveness. FAQsWhy does my CPAP mask keep coming off at night?