How to Stop a Leaking Water Heater Before Damage is Done

Flooding caused by a leaking water heater can be one of the most aggravating and damaging home disasters you will ever experience.  In addition to the mess caused by gallons of hot water spilling onto your floor, there is also the expense of cleanup and repairs.  If your home has a water heater storage tank, here’s how you can prevent leakage in the first place and turn off the water supply automatically to prevent catastrophic flooding using an automatic water shut off valve should the water heater malfunction.Leaking water heater damage can be prevented



What Causes a Leaking Hot Water Heater?

Conventional storage water heater tanks are the most popular type of water heating system for a single-family home, providing a ready reservoir of 20 to 80 gallons of hot water.  They operate by releasing hot water from the top of the tank when you turn on the hot water tap. To replace that hot water, cold water enters the bottom of the tank, ensuring that the tank is always full.  Water heater tanks are typically fueled by natural gas, propane, fuel oil or electricity.

Water leakage around the base of the tank can be caused by leaking valves, connections, or from the tank itself.  Possible causes include:

    • Faulty T&P (temperature and pressure) relief valve
    • T&P valve leak due to excessive pressure, overheating or stuck
    • Leak from overhead or nearby plumbing connection
    • Leaking water tank (corrosion likely)
    • In an electric water heater, leakage from a loose heating element bolt(s) or bad gasket

If you are handy and want to tackle repairs to your leaking water heater yourself, the website gives good instructions for fixing leaky gas and electric water heaters.  Otherwise, we recommend calling a licensed plumber.


Avoid Leakage Through Proper Maintenance 

The U.S Department of Energy recommends routine maintenance for storage water heaters to keep the unit operating properly and efficiently and to prevent leakage.  Procedures include: 

    • Flushing a quart of water from the storage tank every three months
    • Checking the temperature and pressure valve every six months
    • Inspecting the anode rod every three to four years. 


Prevent Flooding with a Water Shut Off Valve

To prevent flooding due to a leaking water heater, install an automatic water shut off valve that will detect the presence of water beneath the water heater and turn off the water supply before there is extensive damage.


How water shut off valves work — Automatic water shut off valves generally consist of a high-quality brass valve, an attached electric control box, and moisture sensors. The valve installs “upstream” of the water heater directly into the plumbing line.  The moisture sensors are placed on the floor under the water heater or in the drip pan.  If a leak is detected, the sensors send a signal to the control box which closes the valve and turns off the water supply. The valve stays closed and the water remains off until you manually reset it.


Alarming function – If a leak is detected, the water shut off valve sounds an alarm to let you know it has been activated.  More advanced units can also be connected to a home alarm system or auto-dialer to send out phone, text or email alerts to you when you are away.


Watts Flood Safe is the only shut off valve that also turns off powerRecommended Models 


The economical FloodStop FS-¾ NPT v4 is a reliable, basic water shut off valve for single-point protection of your water heater.  It is also lead free.  It can be hooked up to a Sensaphone auto-dialer or home security system and costs less than $150.



The lead-free Watts FloodSafe is the only automatic water shut off valve that can also turn off the power supply to the water heater, thus preventing the possibility of a dangerous explosion that can occur in an over-pressure or over-temperature condition.  This model starts at about $225, based on valve size.
WaterCop LeakStop comes with two moisture sensors


The moderately priced WaterCop LeakStop WCLSLF, which starts at about $250 based on valve size, is a robust, American-made lead-free unit for single-point protection of your water heater.  It can be hooked up to a Sensaphone auto-dialer or home security system and is easy to turn on and off.




Routine maintenance to keep your water tank clean of sediment and operating properly will help prevent leakage.  To avoid catastrophic water damage caused by a leaking water heater, install an automatic water shut off valve that will turn off the water supply as soon as the leak is detected and sound an alarm.  Automatic water shut off valves can also be installed around other leak-prone appliances in your home, like washing machines, dishwashers and refrigerators. For added peace-of-mind and ease of use, there are also wireless systems designed for whole-house protection. For information on the various wired and wireless models available, including new wireless Z-Wave technology, go to this comparison chart of automatic water shut off valves.




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