Draining an inground swimming pool is a task that demands precision, safety awareness, and technical know-how. Whether you are preparing the pool for winterizing, conducting maintenance, or addressing a potential leak, the process requires more than simply attaching a garden hose. Improper draining can lead to severe structural damage, as the groundwater pressure surrounding the pool can cause the empty shell to pop out of the ground or crack. This guide provides a detailed, step-by-step approach to safely and effectively removing water from your inground pool.
Understanding the Risks and Preparing for the Task
Before you even touch a valve, it is critical to understand the inherent risks associated with draining an inground pool. The most significant danger is hydrostatic pressure, the force exerted by the groundwater beneath the pool. When the pool is full, the water inside counteracts this external pressure. Once the water level drops significantly, the empty shell can become buoyant, leading to cracks or even the pool floating out of alignment. Additionally, draining removes the water that provides lateral support to the walls and floor, increasing the risk of collapse in certain soil conditions.
When Drainage is Necessary
You generally do not need to drain your pool completely. Most maintenance, such as cleaning the tile line or performing plaster repairs, can be done with the water at normal levels. However, specific scenarios necessitate a full or partial drain:
- Conducting extensive interior repairs or replastering.
- Removing significant calcium deposits or stains that cannot be cleaned chemically.
- Winterizing in regions where freezing water could damage the structure (though many professionals advise against complete winter draining).
- Addressing a persistent leak that requires detailed inspection of the shell.
Required Equipment and Safety Measures
Relying on the pool’s main drain is not the correct approach for draining, as that system is designed to circulate water, not remove large volumes against gravity. You will need specific equipment to create the necessary siphon or mechanical pull. The primary tools include a submersible pump, a large garden hose, and a backflow prevention device. Safety is paramount; always ensure the pump is unplugged before handling the cords or placing it in the water.
Essential Tools Checklist
| Submersible Utility Pump | Handles the heavy lifting of water out of the deep end. |
| Prime Pump or Hand Bulb | Used to initially start the siphon in the hose. |
| Backflow Preventer | Attaches to the hose to prevent contaminated pool water from re-entering the clean water supply. |
| Garden Hose (50+ ft) | Sufficient length to reach a lower discharge point away from the foundation. |
The Siphon Method: Step-by-Step Guide
The most common and cost-effective method for draining an inground pool is creating a siphon, much like the old trick of sucking on a hose. This process uses gravity and atmospheric pressure to move the water without requiring the pump to lift it the entire distance. While effective, it requires patience and careful positioning to initiate the flow.
Initiating the Siphon
- Place the submersible pump in the deep end of the pool to act as the primary mover.
- Run the hose from the pump to the desired drainage location, ensuring the end is lower than the pool surface.
- Fill the hose with water and seal one end to prevent air from entering.
- Submerge the sealed end underwater at the drainage point, keeping the exit lower than the intake.
- Use the prime pump to remove the air from the hose, allowing gravity to take over and create a continuous flow.
Mechanical Pumping: The Faster Alternative
If you are dealing with a large volume of water or need to drain the pool quickly for repairs, using a submersible pump in conjunction with a floating float switch is the superior method. This mechanical approach is significantly faster than a siphon and provides greater control over the drainage rate. It is particularly useful if the discharge point is uphill or if you need to empty the pool below the skimmer level.
Operating a Pump System
- Position the pump in the shallow end where it can remain submerged as the water drops.
- Attach a backflow preventer to the discharge hose to protect your local water supply.
- Run the hose to a storm drain or a low-lying area of your yard that can handle the volume.
- Monitor the water level continuously; never let the pump run dry, as this will burn out the motor.
- Stop the process once the water reaches the manufacturer's recommended minimum level, usually a few inches above the main drains.
Addressing Water Disposal and Regulations
Before you begin, you must verify local regulations regarding water disposal. Many municipalities prohibit draining pool water down the storm drains because the chlorine and chemicals can harm local waterways and treatment facilities. In most cases, you are required to drain the water onto your own property, ensuring it flows to a place where it will not erode soil or damage vegetation. If you must discharge to the street, contact your local public works department for specific guidelines.
Post-Draining Inspection and Recovery
Once the water has been removed, do not abandon the empty shell. An empty pool is vulnerable to wind and weather. If the pool is out of level, the hydrostatic pressure is unbalanced, which can cause the walls to bow. To prevent this, keep the pump running at a low level or place temporary weighted bags inside the pool to provide lateral support. Before refilling, inspect the liner or plaster for any damage incurred during the draining process, and ensure the water balance is correct to avoid shocking the system when you restart the pool.
