What water should I use in my humidifier?

Manufacturers recommend using Distilled water. Distilled water is the purest form of water and can be purchased from some supermarkets, Big W and Autobarn.

If you can’t find distilled water locally, the next best option is demineralised water which can be found in the laundry aisle of most supermarkets.

Filtered water or water that has boiled and cooled down is often used when distilled water cannot easily be found.

Do not use plain tap water. While tap water is safe to drink, the impurities will cause sediment and mould growth to form on the bottom of the water tank, especially if not cleaned regularly.

We recommend rinsing every morning and not to leave water in the tank during the day. If you don’t clean the water tank regularly sediment build up will cause corrosion and ultimately the water tank will begin to leak.

Why do I sometimes get water in my mask or hose?

Make sure you do not overfill the water tank. Around 1/3 to 3/4 is usually best.

Turn down the humidifier setting. Try 2, 1 or even 0 (see further details below)

It can be quite common to wake up due to;

  • A cold or a runny nose.
  • Cold air from the mask vent disturbing you or your bed partner.
  • Water droplets / moisture in the hose or mask due to condensation.

A hose cover may help, or sometimes a heated hose may be needed to dry out the moisture.

How do I adjust my BMC Resmart Humidifier?

There may be times when you need to adjust the humidifier heater setting of your BMC CPAP Machine.

Typically the BMC CPAP Machines have SIX heater settings;

0 = OFF = No humidification

1 = Minimum humidification = less moisture

5 = Maximum humidification = more moisture

To adjust the humidifier setting, first make sure the machine is plugged in with the display showing, but no air blowing.1. Press and hold down the bottom right ''Ramp'' button for a few seconds until "HEATER" appears on the screen.2. Press the “Ramp’’ button once quickly and you will see the cursor start to flash.3. Now press the "+" or "-" button to increase or decrease to the desired heater setting. Maximum = 5, Lowest = 1, OFF = 04. Now press the “Ramp’’ button once quickly to stop the cursor flashing. 5. Press the "-" button until you see the word "SAVE" appear on the screen.6. Press the "Ramp" button once quickly to save the setting. The machine will beep and return to the main screen.

BMC Screen


  • The heated humidifier adds moisture to the air. It is not designed to heat the air.
  • In winter you may wish to reduce the amount of humidification (moisture) as cold room air meeting warm breath will create natural moisture |(condensation). Too much moisture will cause "çpap rainout" where moisture collects in the hose.
  • We recommend the machine is located lower than the bed, so that if any moisture does develop in the hose, it will drain downwards back to the water tank of the machine instead of downwards towards the body.
  • Last updated 3rd March 2018