Leak Detection, Need Help

I have water seeping into several cracks in the garage floor and need to determine (1) the source of the water then (2) appropriate steps to stop the water from coming in. This problem first started several years ago and I had a leak detection service come out. They could not determine whether the water was from an underground pipe or ground water, and asked to come back when there was more water evident. The problem seemed to "fix" itself, but recently has reappeared. Since we are at the end of the "dry" season, I suspect a leaking pipe rather than ground water. I have not been able to identify a pattern to when the water seeps in; i.e. when we run the washer extensively, over night, etc.

Of course, we have no house plans showing the route of water pipes, but the main inlet to the house is on the south family room wall while the boiler room, kitchen and one bath are on the north side of the house. That means a connecting pipe probably would run directly under the family room and garage...right where the water in seeping through cracks in the slab.

Appreciate recommendations on a reputable leak detection/ plumbing service as well as info on identifying water pipe routes and options for reparing or replacing water pipes.