The water that comes into your house from the main. Suppose the water line
Breaks on your property, say in the back yard lawn. Will your homeowners insurance pay for that? Your water line is attached to the house?

Here is one discussion about that issue but I do not know if it correct:
Homeowners Insurance For Water Main Breaks And Sewer Lines | Balkan Plumbing

My neighbor receives offers all the time from a company that wants to sell him a policy to cover the lines on his property. I don't get the offers and wouldn't buy it anyhow.
Have you discussed it with your home insurer?

External water lines and sewer lines are not covered even though attached to the house. Wind blows a tree down and it crushes your water and sewer lines, covered. Internal water and sewer lines are covered if it is a sudden and accidental break. If, for example, you have a slow drip that causes damage, probably not covered. Water line breaks and floods the house, covered. Leaking roofs are not typically covered if they are old. Wind blows the shingles off and water damages the interior, covered. Key is sudden and accidental. Big issue coming up for Sandy-was the water damage flood or wind driven? Flood is not covered, except through a separate coverage, wind driven water is. WC SHAVER-acronym for basic covered perils- windstorm; civil commotion; smoke; hail; aircraft; vehicles; explosion; and riot.

Yes I had a feeling that was the case. I know the water pipes coming from the city
On your property is your responsibility. Homeowners insurance I guess will not cover it.
But it is remote possibility a water pipe would break outside in the backyard lawn. Thanks

I have known few people who have had waterline problems on their property other than freezing pipes and I don't believe that is a problem in your region. That's not to say that an aging line (depending on what type material it is comprised of) couldn't start springing frequent leaks, but insurance would probably just pay to fix the leak, not replace the line. Baltimore and other cities are having frequent problems with water mains (some as large as 36" diameter and larger). Many of the lines that are failing are 100 plus years old.
One recent failure was in a pipe that had been placed in about 1890.
In your case, a hit on a line caused by some type of excavation or a large vehicle load over the line are most likely your biggest hazards- since your lines are probably more shallow than in areas where freezing is a concern and lines are placed deeper.
Similar concerns for the sewer line but with the added risk of roots.
Keep the roots away, dig test holes and find the lines before digging for shrubs or just about anything else, be careful of what you put in your drains, and keep heavy loads off your yard and your risk is low I believe.

Sounds Good advice. Thanks