Assuming you have not used the sprinkler system for some days, then that would rule out a broken pipe from that.
Take a good closeup smell - if it is septic/sewage water you will know it by smell, plus grass usually grows like crazy and turns lush dark green. Then have your septic tank/leach field checked, or sewer pipe (if on city sewer) run with a color camera by a sewer and drain cleaning contractor to check for breaks.
Assuming is clean water with no sewer smell and not making the grass grow like crazy, then if you have a street meter, turn off all water consumption in the house and check the water meter reading - then again an hour or more later if not moving initially, to see if showing consumption. Of course, no one can use any water or flush or anything in that timeframe.
If no movement on meter, then start thinking wet spots are from french drain outlet, or water seeping downhill from a neighbor, unless your area water table is high.
If still think is a water leak and have no meter or meter is at house, then get a $10-15 metal headed (NOT plastic) stethoscope at box store or phrarmacy, and use it to listen for leak in water pipe. (Will NOT work for sewer leak). Start at exposed pipe in the house near the wall closest to the wet spots so you know what it sounds like - and if you have gas appliances, listen at them first so you know what the gas pilot sounds like, or turn pilots off if you know how to safely relight. Then, making sure not to hit utilities (get locates if unsure) drive a steel rod like a piece of rebar or prybar or metal fencepost or piece of pipe into the ground 6-12 inches (more is better) and a wet spot and without touching the rod with your hand, listen at the top of it with the stethoscope. You will hear even a small leak - move around over the area where the water pipe lies until you find the loudest spot - can usually locate with a couple of feet of where leak is. Generally, stethoscope can hear a leak in the house so small it only makes a vapor mist too faint to even see. Outdoor I have picked up down to less than a gallon per hour leaks, and around 10gph leaks with no problem - obviously, deeper the pipe is the harder it is to hear small leaks, and city noise of course reduces effectiveness too, so do after most area noise is over.
Works for sprinkler system leaks too - put rags or towels over sprinkler heads to stay dry and cut their noise and listen near wet areas for system leaks - will be quite loud because pipe is so shallow. Of course, you will only hear leak if that zone is on, and you will hear water flowing through the pipe while on so you are looking for unusually loud place, not any flowing water sound. Leaks tend to generally be more of a hiss or shrill sound, whereas the flowing water sound is like what you hear when the toilet is refilling - a steady ssshhhhh sound.
Then call your sprinkler repair or landscape guy if there, or plumber if your waterline - or city if on their responsibility area, which is generally everything on their side of the meeter, though in some cold climate areas with meters at the houses, their responsibility staarts at the keybox / shutoff valve at the street.