The main things to look for are strange, musty smells, especially those that persist through basic washing; dark spots that may appear to be dirt at a quick glance, but do not brush away easily; and an increase in symptoms such as headaches, coughing, runny nose, and even asthma attacks. Mold is often hard to see when it first starts to grow, and its effects can be serious well before you can see visual evidence of mold.
If you live in a particularly humid environment, it can be even more difficult to avoid mold growth indoors. Some suggestions from the EPA include: getting rid of carpet and rugs inside your home, using air humidifiers in bedrooms and bathrooms, keeping your home air conditioned properly and making sure all vents and air ducts are cleaned regularly, and repairing any water leaks early.
Frequently washing your equipment is important to prevent the growth and spread of mold, but one thing that often gets overlooked entirely is making sure the water chamber is emptied out, cleaned, and filled with new water daily. If your CPAP machine has a removable filter, make sure that gets cleaned frequently and replaced according to manufacturer’s guidelines so that there is proper ventilation through the machine. Follow all of the manufacturer’s guidelines for properly washing your equipment, including the tubing and mask or nasal pillows.