1. It depends on the type of material the rug is made from and the quantity of the spill. Spills need to be soaked immediately up or they could lead to mold.
The problem is the rug never dries out. Mold grows underneath where you can't see it. If a carpet is over two years old the dirt in it weighs as much as the carpet, so there is a steady supply of mold spores and food. If you have a baby in the house don't let the baby play on the carpet after it has gotten wet.
