If regular water instead of dedicated windshield washer fluid is added to the wiper fluid reservoir, multiple problems may arise. Regular water lacks cleaning and lubricating components; long-term use will increase friction between the wiper rubber strip and the windshield, accelerate the aging of the rubber strip, possibly cause abnormal noise, and even damage the wiper motor in severe cases. In addition, minerals in water may form scale in the reservoir and nozzles, clogging the pipeline and affecting the water spraying effect, while impurities in hard water will leave water stains on the glass surface, which can easily cause glare during rainy conditions and affect driving safety. It is best to check the wiper fluid level regularly and choose windshield washer fluid that meets the JIS D5705 standard. If there is a temporary shortage, distilled water can be used as a short-term substitute, but proper windshield washer fluid should be replenished promptly. The reservoir should be thoroughly cleaned before the rainy season to prevent sediment from mixing with new windshield washer fluid and reducing its effectiveness.
