Air Conditioner Sounds Like Water Running? (Here’s Why)

Your air conditioner should blend into the background of your home, blowing gently but inconspicuously as it cools your home.  When your air conditioner starts making noises, however, there is cause for concern – after all, your air conditioning should sound like air, not water. If your air conditioning is making strange noises, it is time to investigate its source.

When your air conditioner is making water sounds, it is usually related to condensation or refrigerant.  Condensation sounds are normal and easy to fix, but problems with the refrigerant are more serious.  If there is a problem with the refrigerant, turn off your unit and call a professional immediately.

The best way to take care of a problem with your air conditioning is to know the signs of that problem.  Since you are likely to notice strange sounds from your air conditioning, pay attention to these and track down the problem.  Here is what to look for when you hear the sounds of water in your air conditioning unit.

Types of Water Sounds in Your AC Unit 

There are three main sounds that you are going to hear that sound like water – dripping, splashing, and bubbling.  The first two of these are fairly easy to take care of, but bubbling signals a more serious issue in your air conditioner.  Read on to see what each sound means for your air conditioner unit.

Problematic man toward the AC

Dripping Sound

The good news is that if you are hearing a dripping noise coming from your compressor unit, there is no immediate cause for concern.  As part of your air conditioner’s operation, it is normal for a little bit of condensation to form.  This is due to the evaporator coils taking the humidity out of the air and drying it. 

When the water condenses, it drips off into the drip pan, where it is eventually carried away in the drain tube.  If you are hearing loud dripping, you may want to check the drain pan just in case – it is just underneath your indoor coils.  

The pan should be free of cracks and the drain line should be unclogged. If the drip pan is getting full, then you can empty it, and this will reduce the dripping noise.

Dripping sounds can be alarming, but at least this is a fairly benign sound that means your system is functioning as it should.  

Splashing Sounds 

Unlike dripping, splashing represents a slightly more serious problem.  The culprit is likely to be condensation once again.  Slashing means that the condensation is not draining properly.

This can happen occasionally when your evaporator coils thaw after being frozen.  The thaw may cause the drain pan to fill up more rapidly than it can handle.  If you know that your evaporator coils are unthawing, you can head off the problem by helping your drain pan get rid of the water.

Another problem is when your drain line is clogged, which will cause your drip pan to overflow and drip onto the floor.  The good news is that this is relatively simple to fix.  Clean the drain line, and the draining action should resume.

If the problem persists, then there may be something more serious that is going wrong with your air conditioner.  If you cannot resolve the issue, call your local HVAC professional to repair it.


Bubbling is probably the most serious problem of the three sounds.  Bubbling means that there is a pressure issue in your HVAC, and the most likely place that this is happening is with your refrigerant.  Bubbling will mean that your HVAC’s refrigerant is low as well.

Refrigerant does not need to be ‘recharged’ into your HVAC system. The refrigerant stays at a steady level and is used to cool the air that comes through your system.  

The source of bubbling is the refrigerant escaping through small cracks in the coils. This leads to an imbalance in pressure as air is trying to get through areas that it isn’t supposed to get through.

If your HVAC is bubbling, then the problem with your refrigerant has become serious. Refrigerant leaks can cause health problems so stay away from your unit.  You should turn off your system immediately and call an HVAC professional to service your system.

Why Does Your AC Make a Running Sound?

If your air conditioner is making a running sound that sounds like a hiss, whistle, hum, or grind, there is a serious problem with the compressor or the refrigerant systems.  Problems of this nature are serious – you should shut down your HVAC system immediately and refer the problem to a professional.

Refrigerant Leaks 

There are several causes of refrigerant leaks.  Primary among these is corrosion in the tubes, though weakened joints or improper installation can also lead to refrigerant leaks. Electricity bill spikes, inefficient air cooling, or humidity in your home are all signals that something is wrong.

As we stated before, refrigerant line leaks are caused by cracks in the coils of your refrigerant lines. There are two sounds you might hear from your refrigerant lines – hissing, which means that there are small cracks, and bubbling, which means that the cracks are large.

Refrigerant Leaks

If there is a refrigerant leak, then you should turn off your HVAC and call a professional.  Cracks in the refrigerant lines are not a simple DIY job. In addition, if left unattended leaks can bring unhealthy mold, so make sure to get this fixed as quickly as possible.

Handling refrigerant requires certification and licensing.  This is because refrigerant is highly flammable, and it is toxic to humans.  This is why a trained professional should be the one to handle and repair the leak.

Compressor Problems

Compressor issues are among the most expensive to address, so if you are facing a compressor malfunction, you should shut the system down and address it immediately.

The first step to detecting a compressor issue is your air conditioning system making strange noises in the vents, or acting in a way that it should not.  If you cannot isolate the problem within your house, the next stop is the compressor unit.

A compressor that is humming means that the compressor is straining.  If you hear this, then the compressor is working too hard, but shutting it down immediately will likely prevent more expensive repairs.

Air Conditioner Compressor Problems

Hissing means that the pressure in the compressor is too high.  This is related to the problems with refrigerant leaks and internal valve leaks. 

Grinding is the worst sound your air conditioner can make.  This means that the compressor is failing, and is likely beyond repair.  You will have to replace the compressor at this point.

Internal Valve Leak

An internal valve leak in an HVAC unit can cause a hissing noise.  This is related to leaky refrigerant lines – the only difference is that an interval valve has a flap that occasionally is supposed to come open.  A valve leak means that something is coming through that valve even when it is closed.

A problem with your internal valve or refrigerant can be detected if your system is not blowing cold air even though the air conditioner is on.  If this is the case, go to your compressor unit and see if it is functioning normally.

Internal Valve

An internal valve will become worse over time, so a hiss should always be checked immediately to stop the problem from getting worse.  The hissing can intensify into whistling or screaming. The best thing to do, as with all three of these problems, is to shut off the HVAC and call a professional.

When Should You Call a Professional?

You should call a professional to service your unit when the problems with your HVAC involve your compressor unit, internal valve issues, or refrigerant leaks.  In addition, you should involve a professional if your HVAC is acting abnormally and basic maintenance of the system does not resolve the issue.

There are a lot of noises that your HVAC system can make that stem from problems that you can resolve on your own, but the fact that your HVAC is making noise at all suggests there may be more serious issues involved. And when your HVAC is malfunctioning, time is of the essence – letting things go makes the problems get worse.

You can avoid calling a professional by doing basic maintenance on your system, such as keeping your air filters changed and making sure that your vents are clean and unobstructed.  If you have a service contract on your HVAC, then surprises on your system should be reduced to a minimum and any major repairs should be anticipated well in advance.

But if you are experiencing problems with your system, a professional is the best person to call.  HVAC systems are finicky and malfunctions usually require an experienced and trained hand to ensure that the problems do not get worse.

How Much Does it Cost To Fix Your AC? 

If you need to fix your air conditioner, you can expect the cost to average somewhere around $370.  The final cost of your repair will be determined by the type of repair needed, the condition and age of the unit, and the unit’s brand. 

While there are a lot of problems you will need a professional for, there are some problems that you can fix yourself.  Among these is replacing your air filters, programming your thermostat, or for the more advanced DIYers, blower repair.  More complicated tasks will necessitate a professional for safety reasons. 

AC Repair Prices
2022 AC Repair Cost
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If your air conditioner is under warranty the costs to replace the parts are relatively inexpensive. However, when not under warranty, the labor and parts make the cost of replacing the system entirely worth considering.  Unfortunately, the most expensive repairs necessitate a professional and cutting costs by doing them yourself is not usually an option.

Selection of repairs and costs, comparing between cost of professional and DIY

Average Cost of Professional ServiceAverage DIY Cost
Air Filter Replacement$110$10
Thermostat repair$250$150
Blower Repair$300 (under warranty)$300
Condenser replacement$750 (under warranty)Not recommended
Compressor Replacement$900 (under warranty)Not recommended


Air conditioner sounds are alarming, but by paying attention to the problems and tracking them down quickly can help you save yourself a headache.  Problems with your compressor and condenser are the worst problems to have – but fortunately, these parts do not frequently break down, and frequent checkups to your system can ensure that they stay running well throughout your system’s life.

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