I live in PA, in a split level home about 40 years old.years ago i noticed a brown stain in the middle of my basement floor.It could not be cleaned up and got worse the more i tried to clean it up.Now i have another brown stain in the middle of the carpet.Now i realize it is coming from under the carpet.
The basement sits about 4 feet under ground.Our line from our well busted and we just had it replaced.This line runs just next to the basement into the crawlspace.We did have a leak years ago in the well line also. In the basement we have carpet plus a vapor barrier, then there is old commercial grade tile that was not removed for fear of asbestos.
Could the water have come from the well line and traveled across the lawn and under the foundation 5-10ftunder the basement floor?

Yes water can come from many places. It sounds like the stains are a result from the old tile color bleeding through to the carpet. Even if plastic was placed down before the carpet was installed. Water can come through any seams in the plastic or where the seam tape if used failed.
How old is the carpet?
I suggest that you remove it and replace it with tile. Asbestos tile removal is not as expensive as it was a few years ago as there are more folks in this business bringing down the price. Carpet can contain lots of microscopic critters that are not healthy to folks with health issues.
If you have a concern about this. Get the book written by Jeffrey May called "My House Is Killing Me" very well written and you will not put it down until you finish it.Great book for those who have health issues and wonder if the house is causing it.

Thanks so much.The carpet is about 8 years old.How can I tell if the tile is asbestos?what should someone do if there is water coming through the floor.should it be sealed then tile on top?

If the tile is 8" square there is a high likelyhood of it containing asbestos. You can simply break off a small piece 3 or 4 inches square should do and send it off to a lab that tests for this product. Check under enviromental testing in the yellow pages or call your local health department and they can provide you with some names of who does this type of test. Should only cost around $30 - $50 dollars for the test.
As far as the seepage from the center of the floor is concerned. You first need to determine if that is the cause. It could be sewer drain pipes leaking or a host of other things. Leaking water line etc. If you do determine that it is water from the outside. Post another question on how to fix water entry into the center of the floor. There are several folks that write in this site that have more experiance then I.
Do not attempt to seal the floor or walls with paint or dryloc of any kind. It will work for about a year if your lucky and then start all over again. And sometimes be much worse when it does.