ResMed CPAP water leaks are usually caused by rainout condensation or a cracked water tub. The primary fix is using a ClimateLineAir heated tube and adjusting humidity settings to prevent moisture buildup in the hose.
Most of the time when someone calls me about water coming from their ResMed, it turns out to be rainout, not a broken machine. But ignore it and that water can siphon right back into the motor and kill a $900 device. I've seen it happen twice in one month. Address this tonight, not next week.
ResmedCpapSeverity: low90% DIY Success
Time to Fix
5–15 min
Difficulty
beginner
Parts Cost
$6 – $55
Tools Needed
Soft dry cloth, Distilled water (1 gallon jug)
What Does the LEAK-WATER Code Mean?
When a ResMed unit starts pooling water, I first check the nightstand height relative to the bed. If your machine sits higher than your head, gravity turns normal condensation into a steady drip right into your mask. We also see many hairline cracks in HumidAir tubs after high-heat dishwasher cycles, regardless of the dishwasher-safe rating.
Most Likely Causes
Based on aggregated repair data, here is the probability breakdown for this error code:
Warm humid air condensing in cold standard tubing (rainout)40%
Water chamber overfilled above the MAX line24%
Humidity level set too high for room temperature14%
Chamber seal gasket worn or missing12%
Water chamber cracked from dropping or dishwasher use10%
Symptoms You May Notice
You wake up with your face feeling wet and there's a gurgling, bubbling sound mid-therapy like someone blowing bubbles through a straw in a glass.
Water pooling on the nightstand under the machine in the morning, not from a spilled glass but seeping from the unit itself.
The inside walls of your hose are visibly wet when you pull it off, with actual water droplets you can see running down the inside when you hold it up to light.
Bursts of moisture or tiny water droplets hitting your nose or mouth through the mask, usually in the first hour of therapy when the bedroom is at its coldest.
A sloshing or splashing sound when you roll over in bed or pick up the tubing to adjust it.
Can you reset a Resmed cpap to clear the LEAK-WATER code?
On the AirSense 10, press Home, go to My Options, then Climate Control, and set both Humidity and Tube Temp to Auto. For a full reset: Settings, Device, Reset Device. On the AirSense 11, tap My Device, then scroll to Factory Reset. After either reset, confirm Climate Control Auto is active. If you've got a ClimateLineAir hose plugged in, make sure the tube heater indicator shows up on the screen before you go to sleep.
Tools Required for Diagnosis
Soft dry clothDistilled water (1 gallon jug)Bright flashlight or phone torch (for spotting hairline cracks in the tub)ClimateLineAir heated hose, ResMed part 37298 (for fixing rainout)Replacement HumidAir tub, ResMed part 37311 (if chamber is cracked)Insulating hose wrap or sleeve (temporary rainout workaround)
Diagnostic Checklist
Follow these steps in order. We start with the easiest external fixes before opening up the machine.
Replacement Parts
If your diagnostic testing proves the component has failed, you will need a replacement. We recommend OEM parts over aftermarket for water-handling components.
Part Name
OEM Number
Estimated Price
ResMed ClimateLineAir Heated TubingN/A · $35–$55
N/A
$35 – $55
ResMed HumidAir Water ChamberN/A · $25–$45
N/A
$25 – $45
ResMed HumidAir Water Chamber Seal GasketN/A · $6–$15
N/A
$6 – $15
Frequently Asked Questions
What is CPAP rainout and why does it happen?
Rainout is what happens when warm, moist air from your humidifier hits the cooler plastic walls of your tubing and dumps its moisture before it reaches your mask. Think cold beer can on a humid summer day: the outside gets wet because cold air can't hold moisture. Same principle inside your hose. Bedrooms under 68 degrees almost always cause rainout if you're using a standard unheated hose with humidity above 3. The fix is either a heated hose, lower humidity settings, or routing the tube under your blanket to keep it warm enough to hold the moisture all the way to your face.
Can water damage my ResMed CPAP machine?
Yeah, it can absolutely kill the machine. The air outlet sits right above the motor, so if water siphons backward through the hose it goes straight into the electronics. I saw an AirSense 11 completely fried last month because the patient packed it for a work trip with water still in the chamber and it tipped over in the bag. Don't plug it in if you think water got inside. Unplug it, tilt it so any water drains out through the tub slot, and let it dry for 24 hours minimum before you even think about turning it on.
Is the ClimateLineAir heated hose worth the money?
Honestly, yes. Without question. A standard CPAP hose is just hollow plastic and it does nothing to keep that warm air warm on its way to your face. The ClimateLineAir has a heating element inside the tube wall that keeps the air temperature consistent from machine to mask. You can run higher humidity for comfort without any rainout at all. It runs about $100-$130 new but I've seen them used for under $50. Most people who've tried one say they'd never go back to a standard hose. It's the first thing I recommend when someone calls me about rainout.
Should I use distilled water or tap water in my ResMed?
Always distilled. Tap water has minerals that build up on the heater plate and inside the tub over time as white crusty scale. It doesn't wreck the machine overnight but after a few months of tap water, that buildup affects how the heater plate performs and it's a real pain to clean off. Distilled water is like $1 a gallon at any grocery store. ResMed technically says tap water is OK in a pinch, but I've seen the inside of tubs after a year of tap water use. Just buy distilled. It's not worth the hassle.
How often should I replace the HumidAir water chamber?
ResMed says every six months but honestly most people go a year or more without issues if they're cleaning it properly with mild soap and air drying. What I actually watch for: discoloration that won't scrub off, cloudiness in plastic that used to be crystal clear, scratching on the inside surface that can harbor bacteria, or obviously any crack at all. If you're running it through the dishwasher, check it more often because heat cycles stress the plastic. The HumidAir tub (part 37311) runs about $25-$35. Replace it before it becomes a leak problem, not after.