Our home has gray plastic water lines. Someone said these lines are likely going to leak. Our home is 30 years old, don’t you think if the lines were going to leak they would have already?

The lines you are talking about are likely poly “B” lines. While it is true these lines have had a poor history and many homes have flooded from this type of pipe, you need to consider a couple of things before you get too excited. As you said, your home is 30 years...