When you have a leak in your pipes that is caused by your sinks, tub, or your water heater, it can flood your floors and cause water damage all over your house. It depends on how long it has been going on and how long the water has been sitting there. Water can damage your walls, floors, carpets and many other things in your home. It can cause mold, and it can spread throughout your home depending on how much moisture gets to it and how long moisture stays in those areas.
When your sinks have a leak it can rot the walls and the floors. It can bow them down and make them fall apart piece by piece or all at once. It gets them wet first, and then it starts to weaken it. After all that, it will start to grow mold, and you will start seeing black spots on the wood and the dry wall. You will smell a musty odor in the air, which is very toxic because it is from the mold. It can rot all the way through the floor, and if you have a basement it will go down there and will damage and stain things. It will also grow mold down there on your bricks, carpets, and in boxes.
If you have a leak between the walls or in the bathtub, it can leak on your carpet and cause mold to grow under it and rot the floor that the carpet is over. You will start to see black spots around the tub, and your wall will be soaked in water. It will start to break apart around the faucet. As time goes by the wall will start to form a hole, and you will see the mold growth and the water damage.
If your hot water heater leaks due to the cold or just by a cracked pipe, you can have a flood of water on your floor. It can also make it to where you are stepping in it. This means you will have to fix the whole floor before mold can grow because there is too much water damage from it. It happened to my parents one year, and it was cold outside. They woke up and stepped in water; it was all over their house. The leak was caused by the water heater pipes breaking open.
You need to keep an eye on your pipes whether it is cold outside or not because pipes can crack or break at anytime.