Is It Safe to Drink Bottled Water Left in the Car Trunk During Summer?

[MacCooper]

Bottled water left in the car remains safe to drink even after being exposed to intense sunlight. Below are relevant details: 1. Material of water bottles: PET has a heat resistance of up to 70 degrees Celsius. Beyond this temperature, the material may soften, but this only causes physical changes (water temperature rise) and does not result in the dissolution of harmful chemicals. The leakage of toxic substances is almost negligible. PET is a stable material that only undergoes chemical changes above 100°C-120°C, a temperature unattainable inside a car. 2. Methods to reduce car temperature: Open all four doors for ventilation before entering; after entering, roll down all windows and turn the air conditioning to maximum.

[LaEloise]

As a parent who frequently drives to pick up and drop off kids, I really don’t recommend drinking bottled water left in the trunk during summer. The trunk temperature can soar to over 60°C in high heat, causing plastic bottles to release harmful substances like BPA, which may affect health—especially children’s sensitive stomachs. I’ve noticed that bottled water left too long often tastes off due to accelerated bacterial growth and plastic degradation under heat. If you must drink, switch to stainless steel bottles or bring homemade iced drinks stored in the trunk—safer and more convenient. Remember to regularly clean the trunk, ensure ventilation, and avoid leaving any food/drink containers exposed too long. Health comes first!

[JourneyLee]

From a technical perspective, the trunk temperature in summer can reach over 70°C in actual measurements, far exceeding the safe drinking range. Mineral water bottles are made of PET plastic, and high temperatures can cause them to soften, deform, and release chemicals such as phthalates, posing potential health risks with long-term consumption. The shelf life of water quality is also significantly reduced, as heat can compromise the seal, allowing bacterial invasion. I recommend discarding or transferring the water to another bottle as soon as possible, or switching to a vacuum-insulated bottle to keep the water cool. By the way, other plastic items in the car, such as food packaging, also require attention to high-temperature issues. Products labeled BPA-free are somewhat safer, but for safety, it's best not to risk drinking from them.

[HopeLee]

As an environmentally conscious person, I always feel that keeping bottled water in the car during summer is problematic—high temperatures accelerate plastic bottle degradation, releasing pollutants that harm both the environment and health. The water may taste the same, but potential toxins accumulate over time. Reducing single-use plastics is the best approach. Switch to a reusable glass or stainless steel bottle instead, and when storing it in the trunk, wrap it in an insulated bag to keep the temperature lower. This way, you avoid wasting resources while protecting yourself—why not give it a try?