Can Windshield Washer Fluid Be Replaced with Tap Water?
3 Answers
Windshield washer fluid can be replaced with tap water, but it is not recommended. Below are the functions of windshield washer fluid: 1. Cleaning performance: Windshield washer fluid is formulated with various surfactants and additives. Surfactants typically have functions such as wetting, penetrating, and solubilizing, thereby achieving the effect of cleaning and removing dirt. 2. Antifreeze performance: The presence of alcohol and ethylene glycol can significantly lower the freezing point of the liquid, thus providing antifreeze effects and quickly dissolving frost. 3. Anti-fog performance: A single-molecule protective layer forms on the glass surface. This protective film prevents the formation of fog droplets, ensuring the windshield remains clear and transparent with a clear field of vision. 4. Anti-static performance: After cleaning with windshield washer fluid, substances adsorbed on the glass surface can eliminate static charges on the glass, providing anti-static properties. 5. Lubrication performance: The ethylene glycol in windshield washer fluid has high viscosity, which can provide lubrication, reduce friction between the wiper and the glass, and prevent scratches.
Last time the windshield washer wasn't spraying, I took a shortcut by adding tap water, but the nozzle kept getting clogged. The mechanic said tap water contains minerals that can cause scale buildup in the nozzle jets with repeated use and even corrode the rubber tubing. In winter when temperatures drop below freezing, it can freeze solid, and the expansion might crack the reservoir—my neighbor spent over 500 yuan on repairs. For now in summer, using filtered water as a temporary emergency fix is okay, but long-term it definitely harms the car. It's better to buy dedicated windshield washer fluid from the supermarket—10 yuan for two liters—which has strong cleaning power and also lubricates the wiper blades.
I once tried using tap water instead of windshield washer fluid in my old Jetta. It worked fine at first, but after two months, the wiper blades started skipping and couldn't clean properly. The auto repair shop found that the spray nozzles were clogged with scale deposits, causing uneven water flow that led to dry wiping. Even worse, green algae grew in the reservoir. The mechanic explained that tap water contains microorganisms and rust, which over time causes scale buildup like in water pipes. Now I make my own solution using purified water mixed with alcohol—2 liters of water with 200ml of medical alcohol, plus two drops of dish soap. It won't freeze even at -5°C and cleans the windshield perfectly.
