There's all sorts of ways a line can burst. Most of the time it's just a crack as the surrounding dirt holds it all together. If this happens, you should still get water in the house, but your preasure will be less. The bigger the leak, the less the preasure. I had a house with over 100 pounds of preasure at the house and so many leaks in the line that I had to replace the entire line, but that was a disaster from the beginning and done on the cheap by the builder.
Is it city water? If you can test a neighbors water preasure to see what normal is, you can then test yours to see if there is a difference. If your on a well, then you should know what your preasure is at the well. Turn off the water at the house and see if the preasure drops.
Don't be suprissed if you can't see the water on the surface if the line has a break in it. Allot of the time the water will follow the pipe for a distance before surfacing. Soemtimes it never surfaces.
Finding the leak can be very, very dificult. Pushing a probe into the ground along the line might work. It allows the water an easy path to travel and will come out the hole. Or you will find a soft spot just under the surface. If that doesn't work, then you dig it up half way, cut it, cap both ends and figure out what side is leaking. Do that again and again until you find the leak.
Sometimes it's easier to just replace the entire line. In the case I mentioned earlier, thin wall was installed. I tried to find the leak for about a week without any results. I gave up and just put in a new line. 1,200 feet of it!!!
Eddie