As we know water is a substitute for windshield wipers fluid as it is easily available almost everywhere. You might be able to get by with plain water if you live in a place where the temperature never freezes, although even then water does not have the cleaning power of specialized fluid to remove the bug, birds drop, road grime, and other cruds on windshields. The windshield fluid includes ingredients that purify those stubborn messes. The majority of products consist of methanol and other alcohols, such as ethylene glycol. Many also contain small amounts of ethanol or methylated antifreeze to prevent the product from freezing in winter months. The components in the fluid washer work together to provide you with a clean, strip less windshield.
The main advantages of water are that it is less expensive and more environmentally compatible than the windshield fluid. The key drawbacks are the shortage of solutions and detergents and the freezing of the windscreen wash system in your car with 32 degrees Fahrenheit in cold weather.