Plumbing – Why might the water (hot and cold) be discolored/brown

For a couple of months, we've been noticing that our water is brown or discolored. It comes from both faucets. This morning I had run nothing but cold water and noticed it had a brown tint to it.

First we thought it was only hot water, so we replaced the hot water tank and expansion tank which were filthy. But the brown water has come back.

I've called neighbors and they don't seem to have an issue. One neighbor says his water is slightly off color every once in a while. But I don't think it is as bad as mine. He's knowledgeable and hasn't seemed concerned about it.

Since its hot and cold water, it has to be a shared line right? Which would be between the street and the house, right?
But it comes and goes which seems strange. It seems like if there was a crack in a pipe, dirt couldn't get in due to the water pressure, but I don't really know. We did have heavy equipment on the lawn last year and we do have a sprinkler system. But we haven't run the sprinkler in weeks and we're getting brown water today. I also called the town water department a while back and they said no one else has reported an issue.

I really don't want to have a plumber come and just start replacing everything and tearing up my lawn just to rule stuff out. So any advice, input, or personal experience would be greatly appreciated.
Thanks.