Water Damage and Frost-Proof Faucets

Many homes and businesses are now equipped with something called a frost-proof faucet.  These devices are nothing new and have been around for several years.  They have all but replaced the old style water hydrants that had to be wrapped or covered and protected during winter months to keep them from bursting.  But, in order for a frost-proof faucet to work properly, it must be installed properly.  You would think that a plumber would be especially mindful of the consequences if they didn’t do the job right.  In any case, frost-proof faucets do rupture and the resulting water leakage can cause damage, either in a crawl space or inside a wall.  The photographs below show how the copper tube expanded at the point of rupture indicating where the water turned to ice and stressed the tube to the point of failure.  In order to understand what happened, it is necessary to understand that the faucet is equipped with a long stem that runs from the valve handle to the end of the copper tube where the water line is connected.  This is where the valve seat is located.  The valve seat is actually the part that stops the water flow when the valve is turned off.  If the faucet is installed horizontally or pitched upward, water will stay inside the copper tube instead of draining out of the hose connection end when the faucet is turned off.  The faucet must be pitched slightly downward with the hose connection end lower than the water line inlet end. Even if the valve seat is leaking, water must be allowed to drain out of the faucet.  In the case of the faucet in the photograph, when the water froze, its tendency was to expand to approximately 9 to 11% of its volume.  However, because of the enclosure within the copper tube, the ice could not freely expand.  As a result, the tube wall was stressed to a point where failure occurred.

Failed Water Hydrant
Expanded copper wall shown as bulge just to left of water line attachment
Area of copper tube wall failure

About R.J. Hill, P.E.
R. J. Hill is the author of two blogs: R.J. Hill Consulting and the Descendants of James Alexander Hill. Mr. Hill is a registered professional (mechanical) engineer with 42 years of experience, 37 years in private practice. Please visit www.rjhill.com to see the kinds of forensic investigations that Mr. Hill performs.

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