If your home has incurred water damage you may need to have your drywall repaired or replaced. Water can be detrimental to drywall causing an array of things to happen including mold, mildew and rot. These problems can cause long and short-term health problems. Water can be introduced to drywall in many ways including but not limited to roof leaks, plumbing problems and floods. It is important to seek help from a professional who has the knowledge to assess the situation properly.