Why is there water under the car seat?
4 Answers
The reasons for water under the car seat are as follows: Not closing the car window tightly on rainy days: After getting out of the car, not confirming whether the car window is tightly closed can cause rainwater to drift into various parts of the car from the loosely closed window. Over time, water will drip under the car's cabin. Problems with the drainage outlet: After ruling out human causes, if there is still water dripping under the car's cabin, the car's drainage outlets should be checked. Firstly, the car has four drainage outlets: the front two are for draining the sunroof, and the rear two are for draining water flowing on the car. If there is a problem with the drainage outlets, maintenance is required.
I previously encountered a problem with water under the car seats, which caused a musty smell inside the car. It turned out that the roof drainage channel was clogged. Rainwater seeped into the cabin along the A-pillar, soaking the carpet completely. Another possible cause is a detached or blocked air conditioning drain pipe. In summer, if the condensate water doesn’t drain properly after using the AC, it can accumulate under the floor mats. If you’ve recently washed your car or experienced heavy rain, it could also be due to aging door seal strips letting water in. I should remind you that prolonged water exposure can affect the electrical circuits and cause metal parts to rust, so it’s best to address it quickly. First, check for obvious leakage points around the corners of the sunroof and the edges of the carpet. Then, use dry towels to soak up the water before taking the car to a professional shop to inspect the seals or the air conditioning system, to avoid fixing one issue while another leak persists.
Man, my new car has water pooling under the seats already, what a headache. Turns out the drainage holes in the sunroof rails were clogged with leaves, causing rainwater to backflow into the cabin. The AC drain pipe could also be the culprit - especially in summer when running the AC, loose connections or clogs prevent condensation from draining properly, letting it seep under the floor mats. Also watch for improperly closed windows letting rain in, or aged/damaged door seals allowing car wash water to creep through. Don't underestimate this - it could short-circuit seatbelt pretensioners or seat motors. Recommend removing seats immediately to inspect, drying carpets thoroughly with mildew remover, then driving a few miles with windows open to ventilate moisture.
Yesterday, while cleaning the car seats, I noticed the carpet was soaking wet. After consulting a mechanic, I learned there are three common causes: sunroof seal leakage, clogged air conditioning evaporator drain, or damaged door bottom seals. Especially in older cars, hardened seals can allow water to seep in after heavy rain. Accumulated water can lead to moldy floor padding and rusted metal parts. Simple countermeasures include regularly cleaning the sunroof tracks and checking the AC drain for mud blockages during each maintenance. If you discover leaks, promptly dry the wet areas with a hairdryer on the cool setting and air out the seat cushions. If the source remains elusive, conduct a water resistance test, such as pouring water on the roof to observe leakage points.
