How to Drain An Inground Pool Below the Skimmer (4 Easy Methods)

This article will describe how to drain an inground pool below the skimmer level while protecting your equipment. Nearly all pool owners have found themselves needing to remove water from their pool at some point in time. 

Especially in cooler climates, draining water from the pool may be part of the annual winterizing ritual.  Other times, water may need to be removed and then refilled as part of a rebalancing effort.

Depending on the pool plumbing arrangements, different methods may be required when draining water from a pool.  Special care is required as the water level dips below the skimmer, particularly if the pool pump is being used to remove water in order to ensure it does not run dry.

This article will explore four different ways to drain an inground pool below the skimmer to help you find the best means based on your setup:

1. Draining with the Main Drain via Pool Pump
2. Draining with a Skimmer Vacuum via Pool Pump
3. Submersible Pump to Drain Pool
4. Siphoning Water from the Pool 

Important Considerations Before Draining

Before draining your inground pool, a couple of important considerations:

Avoid Pool Pop Out

It is important to note that many pools should not be fully drained (empty) without first consulting an expert.  

Areas with high ground water tables may be at risk of the pool floating or popping from the ground once all the pool water is removed, particularly vinyl-lined pools.   If fully draining the pool, special precautions may be needed to minimize risk of pop-up.  

Keeping water in the pool is a simple way to avoid major costs caused by the pool popping out of the ground.

Location to Divert Water

When draining water from your pool, always direct water to the appropriate source as governed by your local jurisdiction.  Some sewer systems may or may not be designed to accommodate a large volume of water that contains measurable sanitants (chlorine, bromine, etc).  

In general, it is safest to wait to drain until chlorine levels are at zero and pH is balanced to neutral.  In this instance, draining to a downhill location in your yard may be a suitable option, if allowed by local requirements.  

Check the Weather

If draining the pool below the skimmer, you’ll want to double-check the weather. Contrary to what many may think, a hot and sunny day is not ideal to drain your pool.

Hot and dry conditions could damage your pool’s surface if left drained for too long.

If possible, try to drain your pool on a mild and cloudy day. Otherwise, ensure you get it refilled quickly if the weather is looking to be a scorcher.

With those quick precautions out of the way, onto four easy ways to drain water below the skimmer:

Method 1: Draining With the Main Drain via Pool Pump

If your inground pool is configured with a main drain, this is typically the easiest method to drain water level below the skimmer.  

Review your valve setup at your pump inlet to determine next step:

3-Way Valve

The 3-way valve has three ports for plumbing.  Typically one port is from the main drain, one port is from the skimmer, and one port is to the pump.

If you have a 3-way valve at the pump inlet, turn the valve such that the skimmer side is closed.  This will allow water to be drawn from the main drain only, and will prevent the pump from taking in air once water is below the skimmer.

If you are unsure which side of the valve is the skimmer side, you can quickly determine by closing one side of the valve with the pump running.  Visually check whether the skimmer still has suction –suction would indicate that the skimmer is not closed.  If skimmer has suction, then alternate the valve such that the other side is closed and verify suction at skimmer has stopped.

Separate Main Drain and Skimmer Valves

Rather than a 3-way valve, some pools may instead have separate valves on both the main drain and skimmer lines.  

If your pool has separate valves, close the valve on the skimmer line.  This will allow water to be drawn from the main drain only, and will prevent the pump from taking in air once water is below the skimmer.

If you are unsure which valve is the skimmer side, utilize the method described above in the 3-way valve description to determine which line is the skimmer or drain.

Main Drain Valve Only

Some pool configurations may only have a valve on the main drain line for safety purposes.  In this case, there is no means to turn off the suction at the skimmer using a valve.  

If this is your configuration, you can temporarily install a threaded plug at the open port in the skimmer box.  Teflon tape, duct tape, or other temporary sealant may be utilized at the plug to provide a nice seal that will prevent air from being sucked into the pump.

With the plug installed at the skimmer, keep the main drain valve open which will allow the pump to draw water from the main drain.  In this case, the plug is serving the same purpose as a valve for the skimmer.

If plugging the skimmer, it is important to monitor the pump to ensure the plug continues to provide an air-tight seal.  If air leaks by the plug, there is risk that the pump may pull in air and could run dry.  Ensure the pump is turned off immediately if it loses its prime while draining in order to avoid costly damage to the pump.

Once you have configured your plumbing to pull water from only the main drain, you can utilize your pool pump to drain the water.  Here are common steps to do such:

1. Turn off the pump.
2. Connect your backwash hose to either the backwash outlet of your filter or other designated outlet downstream of your pump.  
3. Open your discharge outlet valve, such as the filter backwash valve.
4. Turn on the pump to start draining water.
5. Once the desired pool level is achieved, turn off the pump.

Safety Note: Although there should not be swimmers in the pool when draining water, it is especially important that no swimmers are near the main drain when the pump is only drawing water from the main drain.  This would pose a significant safety risk of a swimmer being entrapped at the drain due to high amount of suction.

Method 2: Draining with a Skimmer Vacuum via Pool Pump

If your pool only has a skimmer without a main drain, it is still possible to utilize the pool pump to drain below the skimmer.  In this scenario, you can utilize your vacuum hose as an extension of the skimmer.  Ensure the pump is turned off before advancing with this process.

For this method, the vacuum head and telescoping pole can remain connected to one end of the hose.  The vacuum head will serve to weigh down the hose at the bottom of the pool, and will also allow you to vacuum while draining the pool. It is essential that the pool-end of the hose remains submerged underwater during the entire process in order to prevent the pump from sucking air.

Once the water falls below the skimmer level, it is unlikely that a tight seal between a standard hose end and skimmer port can be achieved.  If air leaks through the hose-skimmer connection, there is significant risk of damage to the pump. 

The best way to use your vacuum hose when draining below the skimmer is with a threaded hose adapter.  This adapter will help provide a tighter seal at the connection between the vacuum hose and the skimmer port.  

The threaded end of the adapter can be screwed into the skimmer port.  The hose can then be slid over the smooth end of the adapter.  Duct tape can then be applied at the connection between the hose and adapter to provide better sealing if needed.

If you are in a bind in getting your pool drained and do not have the threaded adapter, it is possible to use your standard vacuum hose without adapter.  In this case, you can slide the vacuum end connector into the skimmer port as you typically would when vacuuming.  To prevent the pump from sucking in air at the connection, you can add water directly into the skimmer box with a hose.  

Once the vacuum hose is connected to the skimmer port, the following steps can be used to proceed with draining: 

1. Connect your backwash hose to either the backwash outlet of your filter or other designated outlet downstream of your pump.  
2. Open your discharge outlet valve, such as the filter backwash valve.
3. Turn on the pump to start draining water through the skimmer vacuum hose.
4. Once the desired pool level is achieved, turn off the pump and close the discharge valve.

In either scenario –with or without the threaded adapter– it will be important to carefully monitor the skimmer box and pump as water is draining.  Pump damage can occur if leakage at the skimmer connection causes the pump to lose its prime and run dry.  

Water should be added to the skimmer box as soon as air intake is observed at the pump.  If you find that water needs to continuously be added to the skimmer to prevent the pump from taking in air, you should either re-secure the connection or use an alternative method.

Method 3: Submersible Pump to Drain Pool

Another option that may be used to drain your pool water below the skimmer is through use of a submersible pump.  This method eliminates the need to use your pool pump or filter.

Submersible pumps can be either rented or purchased.  Many of the higher end submersible pumps can remove upwards of 3000 gallons per hour, which will quickly drain your pool to the desired level.  

Submersibles pumps come with a watertight power cord that can be plugged into an electrical source.  A standard water hose can typically be connected to the pump and will provide means to direct the water to your desired location. Some pumps may require a larger backwash hose.

The pump just needs to be dropped into the water and plugged in to get the draining started.  All you need to do is keep an eye on the water level in the pool and turn off the pump once water has dropped to the desired level.

It is important to note that pump performance will be dependent on several factors:

• Length of hose: A longer hose will decrease flowrate due to friction
• Diameter of hose: Larger diameter will provide higher flowrate
• Height of lift: Flowrate will decrease when pumping to higher elevations

When selecting a submersible pump, carefully review manufacturer’s specifications against your needs.

Method 4: Siphoning Water from the Pool

You can use your garden hose to create a simple siphon that is an effective means to drain water from your pool.  This method relies on the siphon effect to transfer water from the pool without using a pump.

The key requirement for siphoning is that the drain end of the hose must be lower than the hose at the pool, as this relies on gravity to do the work.  This method will not work if you are trying to discharge water at a higher elevation than the pool.

Siphoning will take more time than other methods that use a pump.  However, this is the cheapest method and does not pose any risk of damaging your pump.

To perform the siphoning, connect the hose to your outdoor water spigot.  Place the other end of the hose in the pool.

Turn on the spigot until a steady flow of water is observed at the end of the hose in the pool.  Once a steady flow is achieved, quickly disconnect the hose from the spigot and kink the hose that had been previously connected to the spigot to keep water in the hose.  

Walk the kinked end of the hose to the discharge location.  Release the kink and allow water to flow from the hose.  Gravity will continue pulling water from the pool until the discharge end is at the same elevation as the hose in the pool.  

Once the water level has been drained down to the desired level, the hose can be removed from the pool.  

Final Takeaway

Most inground pool owners will need to drain their water below the skimmer at some point or another.  

Determining which method to use will depend on your pool plumbing configuration along with how much time you have to babysit the process. Using your pool pump will likely be the quickest, but it will be crucial that you monitor the pump frequently to ensure it does not run dry.  Using the hose to siphon may take the longest, but is a cheap option that you can walk away from without risk of damaging equipment.

Following these methods along with the appropriate precautions will ensure you have success in draining water far enough below the skimmer for whatever your needs may be!

If you’re considering draining water to clean your pool liner, just know that you may not need to drain any at all in order to keep it looking new.

Happy Swimming!