However, it is rare to see a water heater installed with a drain pan, as it is not required by the current International Residential Building Codes. The general consensus is that since the water heater is in the garage it is not a concern.
The hot water heater platform is generally constructed of drywall which sits on a layer of plywood. The adjacent wall to the interior is constructed in the same manner with insulation installed in the wall cavity. The drywall paper and plywood are both an excellent food source for micro-organisms such as mold. The insulation, when wet, will hold the moisture near the drywall for an extended period of time. Therefore, mold will generally be present in some quantity in areas that are not visible.
The general belief that a water loss in the garage will not have an adverse effect on the indoor air quality within our home is not exactly true. Mold spores find their way into the air by riding on air currents. If you think about it, every time you open and close the garage door or entry door to the interior, you are affecting the air pressure in the garage, which may pick up these spores and move them into the interior of the home. If the room adjacent to the water heater happens to be a bedroom, this may be of concern, as we all spend a large part of our lives sleeping. This has the potential to be a health concern for the person in this room, or to someone who suffers from allergies or asthma.
The simple fix to this problem is to install a drain pan under the hot water heater with a drain line extending to the garage floor. The garage floor is sloped towards the front of the garage where the water will drain. This will help minimize the possibility that substantial water damage will occur to the structure. To have these areas properly remediated if not addressed quickly enough, could cost you as much as $1,500 and more if the water causes damage to the interior rooms.
For more on this or other home care subjects, contact Scott at www.scottsauer.com.