The frustration of failed plumbing components is all too common for property owners. As engineers, we are often asked how the failure of such small, inexpensive components can result in such widespread and costly damage often reaching hundreds of thousands of dollars. The simple answer to this question is that the plumbing component doesn’t cause the damage, rather the large amount of water released due to its failure does. In a very short time frame, water can flood a home damaging everything it touches, and the longer it’s left unnoticed, the more damage it causes. Failures that occur when no one is at home and/or inaccessible shut off valves contribute directly to the magnitude of damage as they allow water to flow unchecked for hours.
To mitigate the damage, homeowners are given a few procedural precautions: have your home checked on every 2-3 days while on vacation, turn off the main water supply when you leave for extended periods. Further, homeowners have had the option of installing a water/leak detector for some time now. These devices sense water in the area they are located and set off an alarm notifying people in the vicinity that there is a problem. The most common design for water detectors is a small cable that lies flat on the floor. When water contacts the cable, a short is created in the cable, triggering an alarm. Increased smart home technology also makes it possible to receive notifications of a water loss online or through your phone. Some water detectors even offer the possibility of having an electronic valve installed in conjunction with the detector so that the main water supply may be turned off remotely. However, water detectors are still restricted in functionality as they must be in contact with the water to set off the alarm and often require a source of electricity (battery or electrical plugin).
Another engineering solution is an auto-shut off connector. These are water supply lines (such as those for toilets) that shut off downstream water flow when the flow rate exceeds that of normal operation. To achieve this, most shut off connectors utilize a spring-loaded valve inside the supply line. As water flow rate increases, the spring is compressed until eventually the water flow is completely cut off. Once closed, the valve must be reset and will not reopen with decreased water flow. Auto-shut off connectors are connected directly to the water source and act to cut off water instead of notifying users of a water leak. As a result, they provide an immediate response to certain water losses. They are also purely mechanical solutions that do not require an electricity source or maintenance. However, auto-shut off connectors only work for certain water losses where there is a notable increase in flow rate (burst, fractured, or cut supply lines) and are not suitable to prevent slower long-term water losses due to pin hole leaks or leaks that are not due to a failed supply line. In addition, auto-shut off connectors rely on a predetermined flow rate for fixtures and require a multi-step process to reset once tripped. As a result, many homeowners have expressed frustration with auto-shut off connectors that have cut off the water supply even when there is no leak or failure.
A recent advance in auto-shutoff connectors couples the mechanical shut-off with a current sensing device. These devices are meant to function specifically with water using appliances, such as a washing machine, to only allow water flow while the machine is turned on. If water flow is sensed without current being pulled by the appliance, the water will be shut off. Unfortunately, this also has limitations. It is only applicable for fixtures/appliances that draw a current (won’t work for toilets or faucets, etc.) and does not account for failures when an appliance leaks or malfunctions while in operation.
Currently, no perfect water loss prevention solution exists. Both water detectors and auto-shut off connectors have their benefits and limitations. With the increase in smart home technology, we can expect an increased number of more advanced engineering solutions to become available. In the meantime, homeowners must remain diligent and wait for technology to catch up.
Andrea Jeffery, P.Eng., M.Sc.