Inspectors disagree over water heater setup
Q. The home we are buying is 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?
A. This is one of many code requirements that give rise to debate among building officials and home inspectors, and there is validity to both points of view. An essential thing to keep in mind is that 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 purpose of the relief valve is to release 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 in 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, therefore, could be standpipes, laundry sinks, floor drains and the like.
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.
City and county 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. Your home inspector apparently agrees with that perspective. Extending the discharge pipe to the exterior may not be required by your city, but it is arguably a good idea.
• To write to Barry Stone, visit him on the web at www.housedetective.com, or write AMG, 1776 Jami Lee Court, Suite 218, San Luis Obispo, CA 94301.
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