How to Safely Drain an Inground Pool

Draining an inground pool is not a task that should be taken lightly. Unlike simple household tasks, like draining a bathtub, there are several factors to consider to ensure you don't damage the pool or face expensive repairs. One of the most concerning risks is the potential for your pool to "pop" out of the ground due to changes in water pressure. To prevent this, it’s essential to follow the right steps and take appropriate precautions.

In this guide, we'll walk you through the process of draining your inground pool safely and effectively, helping you avoid costly mistakes and ensuring the pool stays in great condition.

Key Precautions When Draining an Inground Pool

1. Understand the Risk of Pool Pop

If you live in an area with a high water table, draining your inground pool can cause significant issues. Without the weight of the water, the pool may shift, and in extreme cases, even pop out of the ground. This is a risk for all pool types: concrete, vinyl, fiberglass, and gunite.

To minimize the chances of this happening, consider draining only half of the pool water if possible, and refill it as soon as possible. If you need to perform repairs or maintenance, you may need to drain the pool completely. In such cases, it’s recommended to consult a professional to avoid costly damage.

2. Avoid Draining During Wet Weather

Draining your pool during or right after heavy rainfall is not advisable. Saturated ground increases the chances of your pool being pushed upward as water escapes. Wait for dry weather before draining, allowing the ground to dry out completely.

3. Properly Dispose of Pool Water

Disposing of your pool water correctly is essential to avoid further complications. The best option is to drain the water into a sewer cleanout if possible. Never allow water to spill out onto the ground around your pool. This could lead to increased pressure under the pool, heightening the risk of pool pop.

4. Ensure Proper Drainage Direction

If you're draining the pool into a sewer or a storm drain, make sure the drainage hose is directed downhill. This prevents pooling water from collecting around the drain, which could increase pressure and create additional risks. In case of any clogging, this simple measure ensures water safely moves away from your pool.

5. Use Hydrostatic Pressure Relief Valves

Your inground pool may have hydrostatic pressure relief valves, designed to help prevent the pool from popping by allowing groundwater to escape under the pool. These valves are typically located in the pool's floor, and they should be opened only once the water level has dropped significantly.

Hydrostatic valves are important because if groundwater accumulates under the pool and has nowhere to go, it could create enough pressure to lift the pool. Opening the valve allows the water to escape safely and prevents potential damage.

Steps to Safely Drain Your Inground Pool

1. Rent or Purchase a Submersible Pump

To begin, you’ll need a submersible pump to start draining the water. You can rent a pump from your local hardware store or purchase one for future use. Place the pump at the deepest part of the pool (the center of the deep end), ensuring that the drainage hose is long enough to reach your disposal location.

2. Monitor the Draining Process

As the pump starts removing the water, keep a close eye on the hoses and cords. Make sure they remain securely connected and that the drainage hose remains directed towards the proper disposal location to prevent flooding.

3. Remove the Pump When Water is Low

Once the water level gets low and the pump can no longer extract any more water, you’ll be left with a small puddle at the bottom of the pool. This is normal and won’t interfere with the chemical balance once you refill the pool.

4. Open the Hydrostatic Pressure Relief Valve

At this point, it's time to open your pool’s hydrostatic pressure relief valve. This will allow groundwater that may have accumulated underneath the pool to escape, reducing the risk of the pool lifting out of the ground.

5. Perform Any Necessary Pool Maintenance

Now that your pool is drained, you can complete any necessary repairs or maintenance. Whether you’re patching up the liner, fixing leaks, or resurfacing the pool, be sure to act quickly. Leaving a pool empty for too long can damage the liner, so aim to refill the pool within a week.

6. Replace the Hydrostatic Pressure Relief Valve

If you removed the valve during the draining process, be sure to replace it before refilling the pool. You might need a new valve plug, as the original one may have become damaged. Use Teflon tape on the threads to ensure a secure, leak-free connection.

7. Refill the Pool

To refill the pool, use garden hoses to bring fresh water into the pool. Keep an eye on the water level, and when it reaches about halfway up the skimmer, turn off the hoses.

8. Turn on the Pool Pump

Once the pool is filled to the correct level, turn on your pool pump. It may require priming, especially if the pump has been off for a while. Let the pump run to ensure proper circulation.

9. Balance the Water

After refilling, you’ll need to test and balance the water chemistry to ensure the pool is safe for swimming. Adjust the pH, alkalinity, and chlorine levels as needed before using your pool.

Final Thoughts

Draining an inground pool may seem like a daunting task, but with the right preparation and attention to detail, it can be done safely. Following these steps ensures your pool remains in great condition while avoiding costly mistakes. If you're unsure about any step, especially if you're dealing with a high water table or need extensive repairs, it’s a good idea to consult a professional pool technician.

By properly maintaining your pool and understanding how to drain it safely, you can extend its lifespan and keep it looking great for years to come. Whether you need to make repairs, repaint, or simply give the pool a deep clean, these steps will help you complete the job with confidence.