Have you ever wondered how long it takes to drain a water heater? Perhaps you’re looking to perform maintenance on your heater or are curious about the process. Whatever the reason, this is one of the basic DIY water heater maintenance tasks you should know how to do.
Draining a water heater can take 30-60 minutes. The time depends on several factors, including the size of the tank and the amount of sediment buildup.
Why Drain Your Water Heater?
Over time, sediment and minerals from the water supply can build up at the bottom of your water heater tank. This buildup can damage your unit, causing the water heater to keep turning off and reduce its efficiency. Draining your water heater regularly can remove this sediment and prolong its lifespan.
Besides, draining your water heater can also help remove any bacteria or rust that may have accumulated in the tank. This is especially important if you live in an area with hard water or have an older water heater.
You will also want to drain your water heater if you perform maintenance, such as replacing the heating element or flushing out any remaining sediment.
How Often Should You Drain Your Water Heater?
Draining your water heater at least once a year is recommended, but this can vary depending on your usage and water quality. If you notice your water heater making loud noises or the hot water running out quickly, it might be time to drain the tank.
Steps to Drain Your Water Heater
Here are the basic steps to drain your water heater:
- Turn off the power/gas to the water heater. There should be a switch or knob near the water heater that shuts off the power or gas supply. This prevents the heating element from turning on during draining.
- Attach a garden hose to the drain valve at the bottom of the water heater. The drain valve is usually a white PVC-type pipe protruding from the bottom.
- Extend the garden hose to a nearby drain, bucket, or outdoors away from basement access points. Ensure the hose’s end is lower than the water heater to allow gravity drainage.
- Open the drain valve by turning it counterclockwise. This will allow the stored water to begin draining out through the hose.
- When no more water is draining out, close the drain valve by turning it clockwise until fully closed.
- If the tank is draining for maintenance, you can now clean, flush, or repair the bottom of the tank.
- Refill the tank by turning the water supply back on. Open nearby faucets to allow air to escape as the tank fills.
- Once the tank is fully refilled, restore the power or gas supply. Check for leaks before using hot water.
Factors That Determine How Long It Takes to Drain a Water Heater
Size of Drain Valve and Hoses
The diameter of the drain valve on your water heater and the thickness of any hoses attached impact flow rate and drain time. Newer water heaters typically have 3/4-inch drain valves, while older models may have smaller ones. Larger-diameter valves and hoses allow water to drain out more quickly.
Upgrading to a 1-inch drain valve or hose can reduce drain time by 30%. Always use the thickest, shortest hose possible to minimize drain time. Kinked or restricted hoses will dramatically slow the process.
Water Heater Capacity
Perhaps the most important factor is the storage capacity of the water heater itself. Larger water heaters hold more water than smaller ones. Most standard residential water heaters range from 40 to 80 gallons in capacity.
Draining a 60-gallon tank will take noticeably longer than a 40-gallon version. Professional plumbers generally estimate 1-2 gallons per minute as a typical drain rate, so a 50-gallon heater would take around 30 minutes to drain at that rate fully.
Presence of Sediment Buildup
The amount of sediment accumulated in the bottom of the tank over time also affects the draining duration. Heavy sediment buildup decreases the effective storage capacity as it takes up space that would otherwise be filled with water.
Draining such a tank containing water and sediment sludge may add 15-30 extra minutes compared to a regularly maintained heater with minimal sediment deposits.
Outdoor Temperatures
On cold winter days, draining takes marginally longer since chilled inlet water added to replace drained volumes requires more heating to return to normal temperatures. Conversely, summer heat speeds the process slightly by keeping inlet water warmer. However, the temperature effect alone is small compared to the primary factors already discussed.
Drain Destination
Draining directly to a floor drain, sink, or outside will be faster than draining into buckets or other empty containers that require multiple trips. Gravity flow straight to a large sewage drain is the quickest method.
Water Temperature
Hot water will drain more rapidly than cold water since hot water is less dense. However, the temperature difference is minor. Draining a fully cooled water heater vs. one that is still warm won’t make a huge difference in drain time.
Safety Protocols When Draining A Water Heater
- Turn off the water heater’s power or gas supply before draining it. This is critical to avoid potential electric shock or carbon monoxide poisoning.
- Locate the drain valve at the bottom of the water heater tank. It will usually have a hose attachment.
- Place the end of the drain hose into a floor drain, utility sink, or outdoor area away from structures. This directs the hot water away from living areas.
- Open the drain valve slowly to avoid scalding from pressurized hot water. First, secure the hose in place.
- Stand clear of the path of the draining water, as it will be very hot. Don’t try to catch or direct the stream with your hands.
- Let the heater drain completely before removing the hose or closing the valve. Residual water could scald you.
- In case of splashes, wear protective gear like gloves, long sleeves, and sturdy shoes. Goggles are also recommended.
- Ensure the drain valve closes fully and is secure after draining to avoid unintended leaks.
- Ensure the gas is turned off at the source before attempting any tank repairs or cleaning.
- If necessary, consult the owner’s manual for your specific water heater model. Safety should always be the top priority when hot water drains.
So, How Long Does it Take to Drain a Water Heater?
As a general rule of thumb, plan for the following drain times as a safe estimate:
- Standard 40-gallon tank – 15-30 minutes
- 50-gallon tank – 20-45 minutes
- 80-gallon tank – 30-60 minutes
- Over 100 gallons – 45-90 minutes
Stay with your water heater as it drains, and check progress occasionally. Once the steady stream slows to a trickle, it’s fully drained. Shut off power or gas before servicing. Properly disposing of drained water is also important.
With the right preparation and setup, draining your water heater need not be an all-day process. Following these guidelines can help ensure a smooth, efficient drain job when working on your home’s hot water system. Remember to seek professional help if you need it.
