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How to Tell When It's Time to Replace Your Water Heater

A water heater’s lifespan depends on several factors, including water quality, water temperature, and maintenance. As such, lifespans vary anywhere from 8-15 years. Most people will wait until a unit stops working before they replace it, but that's unwise: plenty of damage can be done before a water heater finally gives up the ghost. Noticing the signs of an impending failure can help you save money and property by replacing the unit before an emergency.

Warning Signs

  • Leaks: The most obvious thing to look out for. Sometimes it’s as easy as noticing a puddle of water under the unit. Sometimes puddles may form and dry up quickly, leaving only deposits around the heater. In other cases, corrosion may be the only clue that something’s not right. Should you observe any of these things, a deeper investigation is necessary. Try to track down the source of the leak - sometimes it may not be the heater itself, but one of the fittings down the line. If no clear source is found, call a plumber.
  • Note: The temperature and pressure relief (T&P) valve relieves the water heater tank of stress caused by pressures above 150 psi and water temperatures over 210°F. These valves can and do leak, as well as release larger amounts of water. If this is a rare and short-lived occurrence, you probably don’t need to be concerned - the valve is just doing its job of occassionally relieving excess temperature or pressure.

    If the T&P valve is constantly leaking, it would be wise to test the temperature of the hot water - you can collect a sample from the heater outlet valve, or from the nearest tap. If a thermometer shows it to be unusually hot (around that 210°F range, you may have a bad thermostat in need of replacing. You can check the pressure of your water system using a pressure gauge connected to a nearby faucet or hose bibb. If the pressure is above 80 psi, a pressure-reducing valve and expansion tank should be installed. If both readings appear fine, the T&P valve should be replaced.
  • Noise: Excessive noise from the water heater could be another sign that it’s on the way out. When water is heated, minerals and other solids in it separate and settle - right on top of the burner in a gas-powered heater, and sometimes around the lower element in an electric heater. Without regular flushing of the tank these deposits will accumulate, reducing the amount of hot water available and the amount of heat that reaches the water. The heater compensates for this by running more often, which will eventually ruin both burner and tank. If you hear rumbling, popping or banging coming from the heater, try flushing it. If the issue persists, it’s time to look into a new unit - the old one will likely fail.
  • Pro-Tip: Hard water makes sediment build up even worse in water heaters. Look out for signs of hard water, and have your water tested if you suspect it has a high mineral content. If you do have hard water, a water softener should be seriously considered: softeners can prolong the life of the water heater, and reduce other problems in plumbing and fixtures.
  • Strange Color/Odor: If your hot water is cloudy, rusty or has a metallic odor, the water heater may be on its way out. Cloudiness can indicate excessive sediment buildup. A rusty color or odor suggests the sacrificial anode rod has been fully sacrificed (or that the glass lining of the tank is compromised) and water is corroding the underlying steel of the tank. A replacement is needed. (Learn how to change an anode rod here.)
  • Helpful Hint: If both hot and cold water have a rusty appearance or odor, there’s probably excess iron in the water supply itself. This occurs most often with well water, but can also be caused by old, corroding iron or steel plumbing with municipal supplies. Well water should be tested, and water suppliers can be contacted for a water quality report.
  • High Energy Bills: Most older water heaters were less efficient than newer models to begin with; age - especially when coupled with poor maintenance - only makes this worse. Water heating accounts for a significant proportion of household energy costs (nearly 20% on average), so replacing an inefficient older unit with something newer (and ideally, Energy Star certified) can save a lot - especially when you consider that an older unit will become less and less efficient as time goes on. Depending on your circumstances, a tankless water heater may also be a cost-effective solution.

Replace, or Repair?

Some common issues with water heaters may make it seem like you need a replacement when repair might suffice:

  • As mentioned above, a decrease in the amount of hot water available may be due to accumulating sediment, which can often be flushed out.
  • Water that’s not as hot as it should be is likely the result of a thermostat or heating element gone bad, both of which can be replaced.
  • Burn marks/soot on the unit indicate a problem with venting or the flue pipe - these are potentially dangerous situations, and should be checked out immediately.
  • Similarly, a melted draft hood and/or excessive condensation or corrosion at the top of the unit also point to the water heater’s venting causing backdrafting - get it fixed.
  • Orange flames at the burner (rather than the ideal blue) could be the result of dust and debris, which will often burn off - if it persists, the burner can be cleaned or replaced. A yellow flame indicates a lack of air feeding the flame, and should be addressed immediately by a professional.

A final word of advice: Give your water heater a good looking-over (top to bottom, including associated piping and the burner flame) every six months - this gives you the best chance at catching problems early.


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Frequently Asked Questions

Q. "I read somewhere that turning your water heater down to 120°F can help you save energy and money on your utility bill. Is this true?
A. In a word, yes. However, it is important to bear in mind that many of the people and websites promoting this tactic are not plumbers (who understand how hot water systems work) or doctors (who understand how germs work). Setting your water heater at 120°F may help you save money or energy, but that temperature also creates a prime breeding ground for all kinds of bacteria. We strongly recommend keeping your tank-style water heater set at 140°F or higher to ensure that disease-causing bacteria like legionella (which causes Legionnaires' disease) cannot grow in the tank or in the pipes as the hot water circulates. If you are concerned about the risk of scalding due to the higher temperature, we suggest installing thermostatic mixing valves either at the hot water tank or at key delivery points in your plumbing system to help mitigate the risk of burns.

Q. "Why would anyone need an expansion tank?"
A. Water is incompressible. Unlike air, it's impossible to squeeze any quantity of water into a smaller volume. Where that matters is in "closed" water systems such as a water heater with a check valve (pressure regulator and the like) ahead of the heater. When the water gets heated it expands and that extra volume has to go someplace. Without an expansion tank the pressure could rise to a dangerous level in a closed system. A diaphragm type of expansion tank (such as what we sell) is a pressure vessel that contains a flexible membrane totally separating the water from a captive volume of air. Air compresses and as the water temperature rises, creating extra pressure/space, the air in the vessel accommodates that increase. Thereby preventing a potentially dangerous pressure rise.

Q. "I have a sulfur odor smell coming from the hot water side of my faucets. A friend of mine told me that it might be caused by my water heater anode rod. Is that true and if so, if I remove the anode rod will the odors go away?"
A. Removing your anode rod will not cure the odor problem, will cause damage to the water heater tank much sooner than normal and will void your warranty. In many cases the odor is hydrogen sulfide gas. The source is sulfate reducing bacteria which is present in many water systems. That bacteria in most cases is harmless but thrives in the hot water environment. Water temperatures of about 140°F - 170°F makes for a rich growth medium. This type of anaerobic bacteria feeds off the hydrogen gas produced by magnesium anode rods. Periodic flushing of the tank with bleach solution will reduce the problem. Because there are so many factors we can not guarantee that the odor will be eliminated, but if you have no odor on the cold side of a faucet and only the warm side generally (not 100%), replacing a magnesium anode rod with one of our Aluminum/Zinc/Tin rods can help solve the problem. Some water heater manufacturers' claim that softened water causes the problems, but that is not a proven fact. Removal of the bacteria will also solve the odor problem. Sanitizing the water heater (with safe levels of bleach, etc), will eliminate the odor but only for a variable (relatively short) length of time. A trace amount of H2S gas in the water is another cause of hot water odor but removal of the anode rod will not cure that odor problem either. It is best to always have an anode rod in your glass-lined steel water heater tank.


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