Not all car windshield problems are a result of cracks and chips. Pitting is more insidious, as it happens slowly over time. You can recognize pitting as small chips or scratches that are evenly distributed over the glass.
A variety of situations can lead to pitting. Windshield wipers may be the most common culprit. Old or dirty wiper blades trap sediment, which then scrapes the window and causes scratches. Using wipers on dry windows makes the problem worse. Ice scrapers can cause similar damages when the scraper blade begins to wear out.
Sandblasting is the other likely cause. If you drive on dirt roads a lot or live in windy areas, then the sand blowing into your car can result in tiny pits over the entire windshield surface. Pollution, mainly in the form of acid rain, can also cause pitting because the acidity begins to eat through the surface layer of the glass.
Pitting is more than a cosmetic issue. Glares are a major problem on pitted windows, particularly at night or when driving directly into the sun. The shimmer and sheen created by the pits can majorly impact visibility, which increases the chances of an accident. Even when there are no outside light glares, the pits can create a haze on the glass surface that compromises visibility.
Further, pitted windshields are also weaker since the pits are slowly breaking up the glass surface. A pitted window may be more prone to getting chipped or developing a crack due to this weakness. Small cracks may also more quickly develop into major damage if the glass surface is already damaged by pits and scratches.
Prevention is the best solution, as repairs aren't always possible. Replacing and cleaning windshield wiper blades often can go a long way toward pit prevention. Always using washer fluid when the glass is dry also helps. If you use an ice scraper on your windshield, promptly replace the scraper if it develops chips or rough spots on the blade.
If pitting occurs due to environmental causes outside your control, such as via sandblast damage, then replacement is usually the best option. Sometimes pits can be buffed out if the damage is still minor and superficial, but deeper and more extensive pitting can't be removed so a new windshield is typically recommended in this case.
Contact an auto glass repair and windshield replacement service for more help.