If you can’t find any valve, or if the valve is rusted to oblivion, then call a plumber. But in a true flood emergency, you can also locate the water meter—usually in a box at the curb. Inside is another shut-off valve. Use a wrench or a sturdy pair of pliers, and turn it off.
Warning: this is a public valve, meaning the city owns it. Do it only in a true crisis—like if your house is turning into a pond and your toaster is floating. Otherwise, the water company might send you a grumpy letter.
The bottom line? Practice now, not during a flood. Go find your valves today. Touch them. Turn them a quarter turn just to make sure they move. Label them with a sharpie if you’re fancy. Your future self—dry and calm—will thank you.
And remember: water is a great servant but a terrible master. Next time you hear a drip gone rogue, you won’t panic. You’ll just smile, walk to your secret valve, and whisper, “Not today, H₂O.”