The House Detective: by Barry Stone, Certified Home Inspector
Dear Barry: I am a real estate broker and am trying to resolve a difference of opinion between my plumber and my favorite home inspector. The inspector routinely cites water heaters that are installed without a drain pan, especially when the water heater is on a raised platform in a garage. He says a pan will prevent water damage if there is a leak. The plumber says there is no code requirement for a pan. Who is right, the home inspector or the plumber? Leila
Dear Leila: Your question raises two separate issues. The first involves the plumbing code – whether or not the code actually requires a drain pan under a water heater. The second issue is the wording in the home inspection report. Did the inspector say that a drain pan is required by code or merely that a pan is advised to prevent water damage?
First, let’s look at the Uniform Plumbing Code (UPC). According to UPC Section #510.7: “When a water heater is located in an attic or a furred space where damage may result from a leaking water heater, a watertight pan of corrosion resistant materials shall be installed beneath the water heater with a minimum three-quarter inch diameter drain to an approved location.”
This requirement names two situations where a drain pan is required under a water heater. The first in when the fixture is installed in an attic. Why a person would install a heavy water heater in an attic is a challenge to common sense, but that is not relevant to this discussion. The second and more pertinent situation is when a water heater is installed in “a furred space where damage may result from a leaking water heater.”
A “furred space” is a wall, ceiling, or floor surface that has been extended with additional construction material. An example of a furred space is a raised platform in a garage, on which a water heater is installed. When a water heater leaks onto the wood and drywall of the platform, moisture damage is likely to occur. To prevent such damage, a drain pan with a ¾-inch drainpipe is required by code.
Most home inspectors do not specifically cite building codes in their reports. Instead, they disclose conditions that are defective, unsafe, or that pose potential problems. Regardless of whether your home inspector mentioned the plumbing code, the recommendation for a drain pan under the water heater was valid, and the plumber should be made aware of section #510.7 of the code.
Aside from code requirements, it is hard to understand why a plumber who is installing a water heater would choose not to include a ten-dollar pan under the fixture. Sooner or later, nearly every water heater ends up leaking. A drain pan, known in the trade as a “smitty pan,” is very cheap insurance when you consider the costs of repairing and replacing damaged building materials, not to mention the potential consequences of mold infection. Instead of debating what is or isn’t required by code, plumbers should recommend smitty pans to all of their water heater customers and should agree with home inspectors who recommend drain pans.