Is it legal for a water company to let a homeowners leak continue for 6+ years because the bill is being paid?

My mom has had a leak between the curb and the meter for many years resulting in an incredibly high water bill. Years ago, the director of the water company came out and said the leak isn’t going thru the sewer and refunded her 3 months of sewage. Since then the bills have been billed with the sewage included per water usage. She passed away in October from a years long battle with cancer and since then I have tried to fix the issue with no luck. Her estate is still going thru probate and since I do not own the house, I have been unable to find anyone willing to do a full line replacement. Is the water company negligent for letting her leak continue for so long and charging her sewage that they know she isn’t using which has now become my inherited problem?