List of Reasons For Car Leaking From AC (5+ Main Causes)

This article will explain the “Water dripping under-car AC not on” problem. However, the water dripping problem out from the AC is quite common in cars. Thus in this article, we will give a brief description of the places where the water leak from AC happens and the causes of water leaks from the air conditioning system.

Reasons behind water dripping under the car when the AC is not working

The common cause of water leaking is as follows

  • The evaporator drain is clogged.
  • Seals are Faulty
  • Leaking of Evaporator core

The water leaks from the air conditioning system in a car can be due to several reasons. Moreover, identifying water leaks from the AC during the hot, humid weather is even difficult because due to the weather conditions, the amount of water flowing out from the vehicle AC is already more. Therefore due to the large quantity of water from the AC outlet, figuring out the leak becomes difficult.

The water leak from the AC can happen either inside the vehicle or outside the vehicle.

Water outside the vehicle

Water leak from under the car can be normal, especially during the hot days, when you are using the A/C at full blast. This is because the car air conditioning systems are designed to allow water to flow out of the vehicle. The system cools the cabin by absorbing the humidity from the air. This moisture is then condensed and drained out from the A/C outlet. The A/C evaporator is responsible for the conversion of moisture into water.

When this water is condensed, it is then drained out of the vehicle in the form of drops. However, it is not normal if a puddle of water is formed below the vehicle. If the water drain is much more than regular, you need to stop and get a check done on your vehicle.

The water inside the car

A/C water leaking inside your car is a sign that something is not right with the car’s air conditioning system. The water can leak inside the car from the floor, or it can also be through non-A/C aspects.

For example, if the windscreen or the sunroof on the vehicle is installed poorly, then water can enter inside the vehicle. Moreover, due to corrosion, holes can be formed in the vehicle body, and thus water can enter the car from these holes. To figure out whether the leak is from the A/C, check when the leaking issue starts. For example, if the leak starts during a hot and humid day while turning the A/C on, then the problem is in the air conditioning system.

Common causes of A/C leaks

The evaporator drain is clogged.

The evaporator is responsible for condensing the moisture present in the passenger compartment. This condensed water is then stored in water in the evaporator drain. The water then flows out of the vehicle from the evaporator drain. However, sometimes the evaporator drain in the vehicle can be clogged due to dirt and dust. Similar to the clogging of the drain in the sink, thus it will lead to a collection of excessive water in the drain.

Once the drain overflows, you will start finding puddles in the car’s cabin. This water enters the car’s cabin through the A/C vents. Therefore it is advisable to clean the clogged AC drain because if the water stays in the system for a long time, it can also damage electronic components.

Seals are Faulty

There are several plastic and rubber seals in the vehicle’s air conditioning system. If these plastic or rubber seals are damaged, then water can seep from the air conditioning system to the vehicle’s cabin. Thus to fix this issue, you must get the seals changed in your vehicle.

Leaking of Evaporator core

An evaporator core is similar to a radiator. However, this evaporator core can get clogged due to leaves or inorganic material entering the coil. The foreign particles enter the system through the air intake vents. When these materials break down, they become corrosive and cause the evaporator core to rust and thus allow the water to leak.


In this article, we have addressed the “Water dripping under-car AC not on” problem. FOr address the issue, we have explained the various causes of water leakages due to A/C. Moreover, we have also given you a brief description of the water can enter the various places.

Frequently Asked Questions (FAQs): Water dripping under-car AC not on

Why is water dripping from my car?

If water is dripping from your car, it can be due to the A/C or the coolant. The coolant may leak due to a broken hose or a damaged seal.

Should I turn off the AC if it’s leaking?

If the refrigerant leaks from the A/C, turn the A/C off immediately. Because refrigerant leaks can be dangerous and thus the continued use of A/C with the leaking refrigerant can be harmful.

How can I stop the A/C from leaking?

  • Ensure that the aircon is perfectly installed
  • Clean the filters.
  • Unblock the aircon’s drainage hole.
  • Check for icing
  • Replace refrigerant.