Why Is My Air Conditioner Not Draining Water? (Causes & Solution)

Nothing is worse than dealing with a broken AC unit during the sweltering summer months. If your air conditioner is not draining water properly, it is not just a nuisance – but a possible health risk if left unfixed.

There are several possible causes for your air conditioner not draining water. Read on for more on how to fix this pesky problem.

Why Is My AC Not Draining Water? (7 Reasons)

As mentioned above, there is no shortage of reasons why your AC unit may have stopped draining water. Below are some of the most common causes.

AC Not Draining Water

Disconnected Drain Line

The drain line on most AC units is a thin tube containing condensation. If the end of this pipe becomes dislodged, moisture may not flow efficiently.

If you notice a separated drain line:

  • First, locate the end of the drain line and ensure connection to the AC unit.
  • If not connected, use a screwdriver or pliers to attach it securely.
  • Check for kinks and straighten them.
  • Then, turn the AC unit on again and check if it’s draining correctly.

Connecting separated drain lines is a relatively easy fix – the sooner you catch them, the better!

Clogged Drain Line

Excessive amounts of mold growing anywhere is never a good thing. There may be a blockage in your draining tube if you notice large amounts of mold, dirt, and other debris collecting in the condensation plate.

In the case of a clogged drain line, try unclogging it yourself before calling a professional. Use a garden hose or plumbing snake to unblock the pipe, then turn your unit on and see if it drains correctly.

If that does not work, you might need to call a technician.

Rust In The Drain Pan

Rusting on the evaporator coil or within its metal casing may result in your AC not draining water. This lack of drainage could lead to water backing up into your home or even overflowing onto the floor.

In these situations, try cleaning out the old rust from inside by using vinegar or baking soda mixed with warm water. If that does not help, you may need to replace your unit.

Unfortunately, the excessive rust buildup sometimes blocks drainage systems from creating condensation entirely.

Malfunctioning Condensate Pump

If you notice your AC is not dripping water, you may have a faulty condensate pump. They pull moisture from the air conditioning system and into a drainage pipe.

To fix a malfunctioning condensate pump:

  • Check for debris blocking the intake hose.
  • Ensure there is nothing stuck between parts of the machine or connections with another pipe.
  • Look for loose wires. Loose wires may cause power to stop flowing altogether, so fix it as soon as possible.

Call a professional if you do not feel comfortable fixing the pump.

A Dirty Or Damaged Coil

A dirty evaporator coil is another possible cause for no water coming out of the air conditioner drain. Damaged coils affect draining water because they prevent the system from cooling down after running.

You can fix this by cleaning out any debris from the coils that may be present or replacing them if they get too dirty or damaged to work effectively.

Air Filter Problems

Airflow problems may lead to no water dripping from your air conditioner. Bad filters make it impossible for AC units to drain since they cannot freeze excess moisture accumulated inside those areas.

To remedy this problem, check if your vents are open enough to allow a sufficient amount of airflow through them.

Also, ensure nothing is blocking the airways outside, such as grass or weeds.

If none of these tips work, then it might be best to call in an HVAC technician who can inspect your system for any damage and make repairs if necessary.

Faulty Thermostat

If your thermostat is not working correctly, it could prevent the air conditioner from turning on or off when it’s supposed to. Broken thermostats lead to water not draining correctly, as the AC unit will run constantly and never reach a state where it can freeze excess moisture – making it impossible for your AC unit to drain appropriately.

You can fix your faulty thermostat by:

  • Replacing the batteries if they’re running low or dead.
  • Make sure all of the wires are correctly connected and not loose.

You may need a new thermostat if these suggestions do not work.

Why Is It Important For The Air Conditioner to Drain Water?

While some types of AC units rely more on drainage than others, every air conditioner needs to drain to operate effectively. Drainage is necessary because it keeps the air flowing through your home cool.

That said, some unit types do not need as much drainage. For example, portable air conditioner units sometimes have internal evaporator systems. Central AC units do not need to drain very often and rarely need replacing if you catch the drainage problem early.

The condensate draining system helps your AC work by pulling humidity from the air and converting it to water – creating cold air. If an AC unit does not drain (or you do not see any water in the drainage tray), fix it ASAP. An AC unit not dripping water could lead to in-home water damage and mold.

When Does An Air Conditioner Need Water Drained?

Spotting a drainage issue with your AC unit is not as tricky as it sounds – they make themselves pretty well-known. Look for the following signs:

Another sign that your AC unit needs draining is if you see standing water around the unit. That indicates the water may begin creeping its way into your home in a matter of days. Try to catch the root of the problem ASAP, and you may be able to fix it yourself!

When Do AC Drain Water

How To Fix Your AC Not Draining Water (Easy DIY Guide)

Before you start attempting to fix your AC unit, establish any tools you may need, safety concerns, and how to go about repairing the drainage problem.


While these may vary depending on your specific issue, there are a few tools almost every AC drainage unit needs.

Have a vacuum (or wet vac) on hand to clear any clogs, along with a plumbing snake or wire brush. Bring some duct tape just in case, a screwdriver, and a wrench to tighten/loosen pipes. A bucket is also a practical idea if you expect to find plenty of standing water.

Try to find a PVC-friendly cleaning solution to pour down the pipe when you finish – and do not forget your gloves!


Fortunately, this job is relatively safe and poses next to no health risks. The only concerns are mold and mildew buildup.

Some individuals have extreme sensitivities or life-threatening allergies to mold. Ensure you wear a mask over your nose and mouth if you or anyone in your household has a mold allergy.

How To Fix It

Follow these steps to get your AC unit up and running:

  1. Cut the power to your HVAC unit.
  2. Find the point of access and remove the cap. Look for any blockages.
  3. If you think you can grab the blockage with your hands, do so wearing protective gloves. Otherwise, flush the pipe with a vinegar cleaning solution.
  4. Let the solution rest for 30 minutes to an hour.
  5. Repeat every month to prevent your drain from clogging.

If these steps do not work for you, call a technician.

People Also Ask (FAQ)

Here are frequently asked questions pertaining to AC drainage problems.

How can you prevent a condensate line from clogging?

The easiest way to ensure you will not have further issues with your condensate line is to clean it regularly. If you live in a humid or arid climate, clean it monthly.

You can clean the pipe with a vinegar solution or a PVC cleaner.

Can an ac unclog itself?

Although we wish modern technology is advanced enough for this, unfortunately – no. AC units cannot unclog themselves. The longer they accumulate mold or ice, the more likely the unit will flood.

How much does it cost to unclog an ac drain line?

If you decide to hire a professional to fix your AC drain line, your final cost depends on the severity of the condition.

For example, if you need the pipe cleaned, you will most likely pay under $150. However, replacing parts like a faulty coil may cost upwards of $900.


A drain line issue does not typically lead to disastrous results or super expensive fixes if you resolve the problem quickly. Hopefully, our guide has helped you figure out why your air conditioner is not draining water.

Josh Mitchell

Josh Mitchell

My name is Josh and I am obsessed with DIY and improving my family home. HVAC topics can be tricky for homeowners so I decided to share my knowledge on the subject. When I am not working on DIY projects, you can find me at the beach or my local coffee shop.