I'm happy that these haven't sounded off but it's good to know that if there is a water leak we will be alerted. I tested all of them (ear-piercing alarm) before putting them in their respective areas to protect and they worked beautifully. It doesn't take but a few drops of water to set them off which in my opinion is good. I have had them for 6 months now and haven't had to change batteries. We are using them in a bathroom around a toilets, in the laundry room behind the washer as well as under the kitchen sink. I am going to order another set to put under the dishwasher and in other bathrooms. Don't hesitate to get these. They could potentially save you a lot of money should you have an undetected leak. Usually it's too late by the time you see the water!