HOUSE DETECTIVE Inspectors disagree over water heater code

DEAR BARRY: The home we are buying is brand new and was just approved by the city inspector. To be on the safe side, we hired a home inspector for a detailed review. He advised a plumbing repair for the water heater, but the city building inspector disagrees with him.

The water heater is installed in the garage, and the discharge pipe terminates about a foot above the floor. The home inspector says this pipe should terminate outside the building, according to code. The city inspector says the code allows the pipe to “terminate at other approved locations,” and he says this can include the garage floor. He also said the garage floor is acceptable because it is sloped to promote drainage toward the driveway. Whose opinion is right? — Larry

DEAR LARRY: This is one of many code requirements that give rise to debate among building officials and home inspectors. There is validity to both points of view; the plumbing codes and building codes are defined as minimum standards.

The discharge pipe on the water heater is connected to the temperature-pressure relief valve. The relief valve releases steam and hot water if the fixture should ever overheat. Before relief valves became a requirement in the 1960s, an overheated water heater could literally explode. When the relief valve sends hot water through the discharge pipe, it is important that it be expelled where moisture damage is unlikely to occur. With this purpose is mind, the location of choice is outside the building. However, the plumbing code allows the pipe to “terminate at other approved locations,” and many building officials agree that the garage floor is an acceptable location for this purpose.

If you consider the intent of the code, which is to prevent moisture damage to the building and to personal property, “other approved locations” should be places where water damage is as unlikely as it would be if the pipe terminated outside. Examples of other approved locations could be standpipes, laundry sinks and floor drains.

The fact that a garage floor is sloped for drainage is outweighed by the fact that people typically use garage floors for storage of personal property, such as furniture, boxes of books or clothing, electronic equipment, and sundry valuables, all of which are subject to damage if exposed to water. On the safety side of the issue, rust damage could occur to the bottoms of stored metal containers, such as cans of thinner and other combustible fluids.

Building officials are free to interpret the code as they see fit, but there remain practical reasons for terminating a discharge pipe outside the building, rather than inside the garage. Extending the discharge pipe to the exterior may not be required, but it is arguably a good idea.