There's no easy answer to this question, as the replacement of a main water line can vary depending on the make and model of your home, the climate, and a variety of other factors. However, most experts recommend replacing your main water line every 20-25 years. So if it's been more than that since you last replaced your main water line, it might be time for a new one!

It's generally recommended that you replace your main water line every 10 years, but it may be necessary to do so more often if the line is exposed to harsh weather conditions or if there are frequent leaks. If you're not sure whether it's time for a replacement, you can always have a plumber inspect the line to make a determination.