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My Hot Water Turns Cold After a Few Minutes

If you’ve noticed that your hot water is suddenly turning cold after a very short amount of time, the most likely cause is a broken dip tube inside your hot water heater.

You see, some dip tubes (especially ones on older water heaters) are prone to breaking, which allows cold water to mix with the hot water at the top of your tank. And when that happens, you’ll get lukewarm water delivered to you soon after you start using hot water.

In this article, we’ll explain:

  • What a “dip tube” is and how it works
  • What causes a dip tube to go bad
  • Signs your hot water problems are caused by a bad dip tube

Need a professional to diagnose and fix your problem? Just contact us and we’ll send over a plumber right away.

What is a “dip tube” and how does it work?

Your dip tube is a long plastic tube that sits inside your water heater. The tube connects to the cold water pipe and runs down the length of the tank. Its main job is to direct the incoming cold water to the bottom of the tank where it will be heated.

dip tube

You see, cold water naturally rises to the top of the tank once it’s heated. So when a hot water tap is turned on anywhere in your home, water is pulled from the top of the tank (where all the hot water is located) and travels to the appliance.

But if the dip tube is cracked or part of it has broken off, that incoming cold water doesn’t get pushed down to the bottom of the tank. Instead, it mingles with the hot water at the top of the tank, lowering the temperature of the water that is delivered to you.

What causes a dip tube to go bad?

Unfortunately, a lot of water heaters out there were actually manufactured with defective dip tubes that are prone to early failure. Basically, these dip tubes crumbled and disintegrated over time because they were too sensitive to the acidity level in the water.

In fact, in 2000, a class action lawsuit was filed against several water heater manufacturers for installing defective dip tubes from 1993 to 1997 that caused a rash of consumer complaints.

Signs you have a defective dip tube

  • Your water heater was manufactured between 1993–1997. You can check the manufacturing date by looking at the water heater’s serial number. You likely have a model with a defective dip tube if the serial number has the numbers 93, 94, 95, 96 or 97 in the 4th and 5th digit. For example, this water heater’s serial number indicates it was manufactured in 1997, which means it likely has a defective dip tube.
  • Your faucet aerators and shower heads have begun clogging with small white particles (these particles are pieces of your disintegrated dip tube).
  • Your hot water supply runs out very quickly, even when the temperature is set to the maximum settings.

Solution: replace the dip tube & flush your tank

If you’re pretty sure you have a defective dip tube, you’ll need to have a plumber replace it. But you’ll also want to have your tank professionally “flushed” to get rid of any debris from the disintegrated dip tube.

Note: “Flushing” a water heater means draining it of all water and clearing out any residue. This should only be done by a professional as it could cause severe burns or damage to your water heater if done improperly.

Once your plumber installs a new dip tube, your hot water should stay hot for much longer. However, if your water heater is old, the plumber may suggest a complete water heater replacement and should provide a quote for the installation.

Related: When Should I Replace My Water Heater?

Need help from a MN plumber?

If you need a dip tube replacement or still aren’t sure what’s causing your hot water to run out so quickly, just contact us.

We’ll send over a plumber to inspect your water heater and fix your hot water problems for good.