You have a disease, but why? I suspect you have a broken water line behind the meter in the pipe going into the house. Turn off all the water and check your meter to see if it is moving. It should be perfectly still.

Once you get the leak fixed and pipe replaced, I would apply ordinary corn meal at a rate of 20 pounds per 1,000 square feet to stop it. You can do that now even while it is hot. Be sure when the remove the soil to dig out the old pipe that they return all the soil they dug out back into the trench. It should mound up almost an inch, but it will settle back down to level in 3 years.

Thanks for the advice dchall. Water pipes seem to be good & I've got a line on some cornmeal - hopefully I can get that picked up tomorrow or Friday.