If you have recently found some water damage, the next question you have to ask yourself is if the water damage is new, or if the water damage that you found is old. If the water damage is new or old will impact how extensive the water damage is, as well as what you may need to do to stop the water damage from spreading further.
Determine What Material is Damaged
First, you need to determine what type of material you are looking at. If you notice water on your carpet or hardwood floors, it doesn't take very much water to change the appearance, so the damage could be new. If you notice water damage to a really tough material, such as tile or brick, that probably means the water damage is older and more persistent over time, as it would take a lot of water to damage a hard, non-porous material. Porous materials will show water damage right away, whereas it can take longer for damage to appear on non-porous materials.
See If the Water Damage Has Left Rings
Next, you need to look at the pattern the water damage has left behind. Many materials that are more porous end up with stains that have rings if the water damage has been going on for a long time. This happens as water damages the material, dries out, and leaves behind a stain. Then, with old water damage that has been happening for a long time, the area gets damaged again with water, dries out, and leaves a stain. If this process is repeated often enough, it will result in the appearance of "rings" when you look at the water stains.
If the damage has rings, that means the water damage has occurred multiple times over a long period of time
See What the Damage Feels Like
Next, you should physically touch the water stain that you found. If the area is wet, but doesn't feel soft, that probably means that the water damage has just occurred. If the area is both wet, and feels soft to the touch, that means that the water damage has been there for a while, or at least long enough to really soak into the material, and potentially ruin the integrity of the material. Not all material becomes soft after prolonged exposure to water, but many materials do.
Look at the Mold Growth
Finally, look for or at the mold growth. If there is no mold growth, that may mean that the water damage has occurred over the last day or two. If there is some mold damage, then the damage is probably at least two days old. If there is extensive mold growth, that is a sign that the water damage has been there for a while.
Determining how long the water damage has been occurring will help you figure out where the water is coming from and how extensive the damage is. You can also call in a water damage restoration team to help you figure out how old the water damage is and how to address it.