A water leak due to a failed washing machine hose connector caused significant damage to multiple rooms in a residence. The failure occurred at the connection point between the hot water supply hose bib and the washing machine hose, which was installed in an upstairs laundry room. One of Garrett Forensics’ clients sought expert analysis to determine the cause of the failure and whether any contributing factors could have been prevented.
A Garrett Forensics expert was retained to analyze the failed hose and determine the cause of the failure. Both the hot water hose (with the failed connector) and the cold water hose were provided for review and analysis.
A detailed review of the hoses revealed that both the hot and cold water hoses were constructed of rubber with an outer layer of nylon braiding for reinforcement. The connectors were composed of two-piece plastic parts—one section was crimped to the hose with a metal sleeve, while the other section, which threaded onto the water supply, was designed to rotate for ease of installation.
The failed hot water hose connector had fractured at the threaded portion that attached to the hose bib. This missing portion was not included in the materials provided for review, so conclusions were drawn based on the available evidence.
Primary Cause: Water Hammer
The main cause of the failure appeared to be water hammer, a hydraulic shock that occurs when high-pressure water flow is suddenly shut off. This phenomenon frequently happens in washing machines, as the inlet valve cycles open and closed multiple times per wash cycle. Over time, repeated water hammer events create stress on components, leading to gradual weakening and eventual failure.
Contributing Factors: Age and Material Composition
The hose had been in use for over a decade, significantly exceeding the recommended five-year replacement period.
The connectors were made of plastic, a material that is more susceptible to stress fractures and degradation over time when exposed to repeated pressure fluctuations.
The failed section exhibited characteristics consistent with progressive weakening due to repeated stress, rather than a sudden manufacturing defect.
Additional Considerations
Manufacturing Defects: Ruled out, as a defect would have resulted in failure much earlier in the hose’s lifespan.
Over-Pressurization: No evidence of bulging or weak spots on the hose, indicating that water pressure alone did not cause the failure.
Corrosion: No excessive corrosion was observed, aside from normal scaling.
Conclusion
The failure of the washing machine hose connector was primarily caused by repeated water hammer, aging components, and the use of plastic connectors.
Thanks to the expertise of Garrett Forensics, the client gained a clear understanding of the root cause of the failure and was able to assess potential liability and preventative measures for future risk mitigation.
This case underscores the importance of forensic analysis in determining failure causes and preventing costly property damage.
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