Write an article based on this "Scan for moisture inside walls with a moisture meter. Find the cold, leaky part of a wall with an infrared camera. Cut into your drywall to find the source of a leak."
A moisture meter is a piece of equipment which, when placed directly against a wall, will analyze the moisture content of that wall. If you know that you have a leak within a certain wall, but are unaware of the precise location, place the moisture meter at 5 or 6 different spots on the wall. Whichever spot gives the highest moisture reading is closest to the leak. You can purchase or rent a moisture meter at a large hardware store or home-improvement store. These gadgets are frequently used by professional home-inspectors to find leaks or wet walls. Infrared cameras detect heat, and can indicate the temperature of a wall. A leaky, wet wall will have a cooler temperature than the surrounding wall. Train an infrared camera on a wall with a leak, and look to see which section of the wall is the coldest. This will be the section of the wall nearest the leak. When using an infrared camera, hot objects will have red or orange coloring, while cool objects will have blue or purple coloring. You may be able to rent an infrared camera from a professional contractor, a home-improvement center, or from a photography shop. Use a utility knife to score a line about 10 inches (25cm) long into your drywall at the location where you see visible signs of a water leak (mold, discolored drywall, etc.). Then, using a drywall saw, cut along the line you just scored. Cut a hole in the wall large enough for your head to fit inside. Stick your head in the wall and look around until you spot the source of your leak. Enlarge the hole so that you can also insert a flashlight to see better inside the wall, if needed. Often, the patch of wall which shows signs of a leak is not directly in front of the leaky pipe or fixture. Water can drain along the outside of pipes in your walls or trickle many feet down the inside of your walls before the telltale signs of a leak become visible. Both a utility knife and a drywall saw can be purchased at your local hardware store.