How to Drain a Hot Water Tank

By: Contributors  | 
Hand attaches hose to a water heater drain to perform maintenance.
Skipping hot water tank maintenance can lead to significant issues.
Chad Robertson Media / Shutterstock

A water heater should do exactly what its name suggests: heat water and supply your house with hot water. While heating water, minerals and other sediments settle at the bottom of the heater. This process is the main reason you need to know how to drain a hot water tank.

If you live in an area with hard water, the sediment builds up rather quickly and will clog the water heater's drain valve and damage the heater. That's why draining and flushing your water heater at least once a year is so necessary.


While a professional plumber will be all too happy to charge you for this service, draining a hot water tank can be an easy task for DIY enthusiasts. In this article, we'll outline why draining a water heater tank is so important, the tools you'll need for the job, and the steps you'll take to finish the job yourself.

Benefits of Draining Your Hot Water Tank

Regularly draining your hot water tank significantly extends the life of your water heater by preventing the buildup of harmful sediment and minerals that can corrode the internal components over time. Secondly, it improves the energy efficiency of the unit. By removing sediment, your water heater doesn’t have to work as hard to heat the water, leading to lower energy consumption and reduced utility bills.

Draining your tank also plays a crucial role in maintaining the quality of your water. It eliminates accumulated deposits that can negatively impact the taste and safety of your water, ensuring that your household has access to clean, clear hot water. This simple yet vital process, therefore, not only safeguards your investment in your water heater but also contributes to the overall health and comfort of your living environment.


Why Water Heater Drain Is So Important

Occasionally draining a water heater can add years to its life. It prevents the buildup of sediment, typically composed of mineral content and other debris, at the tank's base. Over time, this remaining sediment can lead to several issues: it acts as an insulator, reducing the efficiency of the heat transfer, and can corrode the tank, decreasing its structural integrity.

Moreover, sediment buildup can obstruct water lines, leading to reduced water flow and potential blockages. By draining the tank periodically, you can avert these problems, ensuring that your water heater functions effectively and efficiently, providing your home with consistent hot water.


Risks of Not Draining

Ignoring the maintenance of your hot water tank by not draining it periodically can lead to significant problems. The most pressing issue is the accumulation of sediment, which can overheat the tank and damage its internal lining. This not only shortens the lifespan of your water heater, necessitating premature and expensive replacements, but also poses a safety risk.

Overheating can cause the tank to malfunction or, in extreme cases, lead to failure. Furthermore, sediment can harbor bacteria, which may lead to health hazards, foul smells, and compromised water quality. Regular drainage is, therefore, not just a maintenance task, but also a preventative measure against these risks.


Professional Service vs DIY

How familiar and comfortable are you with handling plumbing tasks? That's really the question here. Professional services offer the assurance of safety and correctness, as they possess the expertise and tools required for the job. This is especially recommended for those who are not comfortable with DIY plumbing tasks.

However, if you have a basic understanding of plumbing and are willing to invest time and effort, draining the tank yourself can be a feasible and rewarding DIY project. It allows you to become more familiar with your home's plumbing system and can save on the cost of professional services.


Tools Needed for DIY Draining

To successfully drain your hot water tank on your own, a few essential tools are required. A garden hose is necessary to channel the water from your tank to a suitable drain or outdoor area. A flathead screwdriver or a valve key is needed to open the drain valve located at the bottom of the tank.

Protective gear, such as gloves and safety goggles, will ensure your safety during the draining process, as you'll be dealing with hot water and potentially sharp components. Lastly, having a bucket on hand is useful for catching any initial water spillage when you begin the draining process. This setup minimizes mess and ensures a smoother operation.


How to Drain a Hot Water Tank

You can call a plumber to drain your water heater, or you can follow these simple instructions and do it yourself:

  • Shut off the heater's heating elements. If it's an electric water heater, turn off the circuit breaker. If it's a gas water heater, turn the thermostat to the "pilot" setting.
  • Turn off the water supply to the tank. The shut off water valve is probably on a copper pipe that runs into the top of the tank.
  • Safely locate the pressure relief valve on your water heater. This valve is crucial for ensuring safety during the draining process.
  • Carefully open the pressure relief valve to alleviate pressure in the tank. This step prevents potential accidents due to built-up pressure.
  • Locate the drain valve at the bottom of the water tank. Attach one end of a standard garden hose to the valve opening. Put the other end of the hose into a floor drain (e.g. a nearby sink or toilet) or outside the house. This is where the water will drain out.
  • Open hot water faucets in your home to allow air into the system, which aids in the draining process.
  • Open the drain valve, where you just attached the hose. Notice the color of the water. At first it will have a dark, rusty color, as it's mixed with the sediment. After you flush a few gallons, you'll notice the water runs clear.
  • Close the drain valve when you see clear water coming out. You can also turn off the hot water tap.
  • After the tank is empty, briefly turn on the water heater's cold water supply. The water heater helps flush any remaining sediment from the tank.
  • Turn the water supply back on and wait for the tank to fill up.
  • Turn the power or gas supply back on after the tank has filled with water.[sources: Hot Water, Chili Pepper]


A Run-Down Water Heater Wastes Energy

Regular maintenance on your hot water tank significantly contributes to the longevity and efficiency of your water heating system. Whether you opt to handle it yourself or enlist the services of a licensed plumber, understanding the importance of this process and being familiar with the steps involved is crucial.

If good water pressure and the availability of extremely hot water mean a lot to you, it's important to ensure that your heating system remains in good working condition. Whether you have a gas or electric heater, you can avoid a lot of unnecessary expense and inconvenience by avoiding the sediment build up.


This article was updated in conjunction with AI technology, then fact-checked and edited by a HowStuffWorks editor.