Instructions on How to Drain a Water Heater Fast and Improve Performance
(updated 2017)


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Why and how to drain a water heater? Does it help fixing the problems? How often should it be performed? Should I be flushing the tank as well? Check out this step-by-step guide to drain water heater fast and easy and for better performance. Draining tips and tricks and how to deal with the problems.

Draining a water heater is recommended by every manufacturer, plumbers and experts due to the benefits it provides; better performance, efficiency and desired power output, longer heater life, safer operation and savings.

This article will cover only tank-type gas water heaters as the process of draining is slightly different from the electric and tankless models. Use the article about electric heater maintenance to learn how to drain a water heater powered by electricity.

Benefits of draining a water heater

Drain valveBrass drain valve

The number one reason why to drain a water heater and flush the system is due to the sediment build-up and dirt collected at the bottom of the tank of the heater, which are affecting the performance and efficiency and increasing the operating costs. This is happening because of the imperfect conditions one tank can be exposed to (hard water, mineral content and rust for example) so regular maintenance, should be applied.

Another important reason for draining is due to the heater's inactivity - during the longer vacation for example, so if the unit is subjected to freezing temperatures during the winter, heater and piping should be fully drained and the drain valve left open. Check out an article on how to winterize a tankless water heater for some info.

Probably, the biggest problem that might happen to one home is the tank leakage and damage it can cause to the surrounding, especially if the water heater is installed in the attic, above the living space. Leaking is usually the result of the loose connections, corrosive action in the tank or broken elements. Draining will reduce or eliminate the danger of leaking, and make the service and replacement viable without further damage.

Note: Even if everything runs well during draining, there may be some spillage when disconnecting the hose.

What you will get after this draining process is the cleaner water, lower utility bills and longer lifespan.

Avoid water damages by installing the drain pan

Drain panDrain pan

During the water heater installation, install the drain or catch pan under it to collect the occasional dripping either during the condensation from the heater's tank, TPR valve or pipe joints at the top of the unit.

Recommendation is to use a metal drain pan with the outside diameter 2" bigger than the tank diameter and to pipe it to an adequate drain to prevent the overflow and leakage. If the water heater is in the attic, the drain pan must be installed. A small device can also be installed under the water heater to alarm when there is a leak.

How can I drain a water heater fast?

The best and easiest way to drain a water heater quickly and safely is by using the utility pump. Check out the pump specs for how many gallons per hour of water can be transferred, what is the power of the motor and what is the maximum temperature of water it can deal with.

Recommendation is to buy a portable electrical pump with at least 1/2 HP, and the 12 V battery operated one, in a case of the emergency and when the electricity is not available.

Note: As the sediment build-up can obstruct the normal water flow, consider replacing an existing drain valve with the ball valve.

If the water heater is installed in the basement - below grade, and there is no floor drain, use the electric pump to transfer water outside. Attach one hose to the utility pump and second hose from the pump to an area away from the house, or into the sump pit and sewer system, if water is not too hot.

emergency plumber

What to do if water is still leaking

Keep in mind that water leaking mostly develops slowly - it is quite unusual to see that pipe or connection bursts. If  the paddle of water is noticed nearby or under the unit, immediately turn the water, gas and electricity OFF on the main valve/switch, to prevent the damage from the leaky unit and either call the professional plumber or make sure to fix it.

Step by step guide how to drain the water heater

water heater drain valve - plastic typeplastic drain valve
  • Turn off the gas at the gas control valve or manual shut-off valve located close to the heater.
  • Close the cold water inlet valve.
  • Open the closest hot water tap to vent the heating system.
  • Use the garden hose and connect it to the drain valve located at the bottom of the heater.
  • Use the other end of the hose and discharge to an adequate drain so it won't cause any damage or injury.
  • You can also use a bucket for this purpose if the draining through the hose is not applicable.
  • Open the heater drain valve and let all the water drain from the tank. Be careful as water might be hot. This is the reason to use the appropriate type of the hose.
  • Once drained, flush the tank as needed to remove the deposits.
  • To refill the tank, close the spigot and follow the instruction how to start the heater.

... or use the video below.

Should I drain a water heater often?

Recommendation is to drain and flush the tank every 6 months, or at least once a year, as part of the regular, recommended maintenance. If it is the first time to drain, and there is a lot of sediment built-up in the tank, the drain valve won't work, or will clog up so you won't be able to close it fully, which will result in some leakage afterwards.

Since most water heaters come with the plastic and low quality drain valves and if it is hard to clean it up or if it gets broken, use the hacksaw blade, hammer and screwdriver to saw and chip out the broken pieces and replace it with the ball valve for easy use and maintenance afterwards.

If nothing comes out, then the water heater is in a great condition.

Tips when draining a water heater

One of the ways to prevent lime and sediment buildup is to install a water softener or apply de-limer solution. This is an additional cost for your budget, so draining and flushing a water heater regularly is the cheapest and simplest solution.

The pressure release valve needs to be open, so air will get into the tank, and water can drain out smoothly. The other way is to open a faucet.

To prevent the risk of burns due to the scalding temperatures, open a hot water tap to allow sufficient cold water enter the tank and lower the temperature.

Don't be surprised if you see dirty or brown water. This is because of all the minerals and sediments that had built up, or due to corrosion.

The floor drain must not be clogged, and should be easily accessible to allow trouble-free operation and service.

Flush the rest of sediments out by turning on the water to the tank, and when the drained water is clear, you are done. Use a bucket for this purpose.

When you drain a water heater, the discharge line must pitch downward from the valve so it can drain completely by gravity. When you fill the heater keep the drain valve closed.

How long does it take to drain?

The time needed to drain water heater depends on the tank and hose size and pressure, but as you could see it is very simple and the procedure can last from a few minutes to over an hour if it gets complicated.

› How to drain a water heater

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