How to Drain a Pool: Step-by-Step Guide

How to Drain a Pool: Complete Guide

Draining a pool is an essential maintenance task that every pool owner will need to perform at some point. Whether you’re preparing for winter, performing repairs, or conducting routine maintenance, knowing how to properly drain your pool can save you time and prevent costly damage to your pool structure and equipment. This comprehensive guide walks you through multiple draining methods, safety considerations, and step-by-step instructions to ensure you drain your pool correctly.

Why You Might Need to Drain Your Pool

Pool owners drain their pools for several important reasons. Seasonal preparation, particularly before winter, is one of the most common reasons to drain a pool. Excessive debris, algae growth, or chemical imbalances may necessitate a complete water refresh. Major repairs, replastering, or equipment maintenance often require a partial or complete drain. Additionally, after heavy rainfall or flooding, you might need to lower water levels to prevent overflow or damage. Understanding when and why to drain your pool helps you make informed decisions about maintenance schedules.

Preparation Steps Before Draining

Before you begin the draining process, proper preparation is crucial for a smooth and safe operation. Start by cleaning your pool thoroughly to remove leaves, debris, and dirt. Skim the surface and vacuum the floor to prevent debris from clogging your pump or drainage system. Next, remove all pool accessories including floats, toys, ladders, and any other items that could interfere with the draining process.

Check local regulations and guidelines regarding pool water disposal, as many municipalities have specific requirements about where pool water can be discharged. Some areas require water to be directed to storm drains, while others have restrictions on draining into yards or streets due to chlorine content and environmental concerns. Turn off your pool pump and heater before beginning any drainage work. Close the skimmer valve and main drain valve to prepare your system for the selected draining method.

Determining the Correct Water Level

The target water level depends on your pool cover type and the season. For pools using a standard tarp or solid cover during winter, lower the water to approximately 4-6 inches below the skimmer. This prevents ice and snow from pushing water over the edge of your pool. If you’re using a mesh cover that allows water to pass through, lower the water level to 12-18 inches below the skimmer. For in-ground pools without a cover or those requiring maintenance work, you may need to drain completely or partially depending on the specific situation.

Draining Methods Comparison

Method 1: Using Your Pool’s Filter System

This method is ideal for partial draining and uses your existing pool equipment, making it cost-effective and convenient. Locate your pool’s multiport valve, typically found on the filter system. Turn this valve to the “Waste” or “Backwash” setting, which bypasses the filter and directs water straight out of the pool.

Connect a backwash hose to the waste port of your filter system, ensuring the connection is tight and secure. Position the hose’s end to direct water to an appropriate drainage area, such as a storm drain or a safe location away from your home and neighbors’ properties. Turn on your pool pump and monitor the water flow to ensure it’s draining properly.

Keep a close eye on the pump during operation and stay nearby to address any issues immediately. Once you reach your desired water level, turn off the pump. Never leave the pump running unattended, as this could lead to damage to your pool’s plumbing system or surrounding landscape. Check your pressure relief valve to ensure it’s functioning properly and preventing damage from groundwater pressure.

Method 2: Submersible Pump Method

The submersible pump method is one of the most effective ways to drain significant amounts of water from your pool. This approach works well for both above-ground and in-ground pools and offers excellent control over the drainage rate.

Step-by-Step Instructions:

Position the Pump: Place your submersible pump at the deepest part of the pool, typically in the deep end. Ensure the pump sits flat on the pool floor on a stable surface to maximize water extraction efficiency. Some pump models come with a small stand or base to keep them level.

Connect the Discharge Hose: Attach a long garden hose to the pump’s discharge port. The hose must be long enough to reach your designated drainage area, such as a storm drain, clean-out pipe, or safe area away from your home. Secure the connection tightly to prevent leaks during operation.

Check Power Connections: Before plugging in the pump, carefully inspect the power cord and all connections for signs of wear, damage, or exposed wires. If using an extension cord, ensure it’s specifically rated for outdoor use and can handle the pump’s power requirements. Position the cord safely to avoid contact with water.

Begin Pumping: Plug in the pump and turn it on, observing the water flow through the discharge hose. Monitor the hose’s end to confirm water is draining correctly and not causing flooding or pooling in unwanted areas. Aim for a safe drainage rate of approximately 12 inches per hour to prevent damage to your pool’s drain line and main drain.

Monitor Continuously: Regularly check both the water level in the pool and the pump’s operation to ensure everything is functioning properly. Be alert for any unusual sounds or vibrations. If the pump begins sucking air (indicated by sputtering or changes in water flow), turn it off immediately to prevent damage to the pump.

Shut Down Properly: Once the water level reaches as low as the pump can manage, typically a few inches from the bottom, turn off the pump. Disconnect the discharge hose and carefully remove the pump from the pool. You may need to remove the last bit of water manually using a wet/dry vacuum or by hand.

Method 3: Hose Siphoning Method

The hose siphoning method is a simple, cost-effective option that works particularly well for smaller pools or situations where you don’t have access to a pump. This method relies on gravity and the principle of water displacement to create a continuous flow.

Submerge the Hose: Start by laying out your garden hose and ensuring it’s long enough to reach from your pool to the drainage area, which must be lower than the pool’s water level. Submerge the entire length of the hose in the pool, pushing out air bubbles to ensure it becomes completely filled with water. You can use the weight of the pool water to help displace trapped air.

Create the Siphon: Once the hose is completely filled with water, cover one end tightly with your hand to create an airtight seal and prevent water from escaping. Quickly move this end of the hose to the designated drainage area, keeping it lower than the pool’s water level to allow gravity to work effectively. The water should start flowing out of the hose automatically once the siphon is established.

Complete the Drainage: Allow the siphon to continue working until the pool drains to your desired level. Once the hose method can no longer remove water (when water levels are too low), you may need to scoop out remaining water manually using buckets or a wet/dry vacuum. Afterward, thoroughly clean the pool to prepare it for the next use or for any necessary repairs.

Blowing Out Water Lines

After draining your pool, it’s essential to remove all water from your plumbing lines to prevent freezing damage during winter months. This step ensures every last drop of water is expelled from the system.

Remove Drain Plugs: Take out all plugs from your filter, pump, heater, and any other equipment that contains water. This allows water to drain completely from the system components.

Use an Air Compressor: Connect an air compressor or wet/dry shop vacuum to the skimmer line. Turn it on and blow air through the skimmer to force water out of the entire line system. Do this carefully to avoid damaging delicate components.

Watch for Bubbles: Continue blowing air until you see bubbles appearing in the pool from the return lines. This indicates that all water has been successfully expelled from the lines. Keep the compressor running for a few additional seconds to ensure complete evacuation.

Plug the Lines: Once the lines are clear of water, plug them with expansion plugs, also called “gizmos,” to prevent water from re-entering the lines during winter. This prevents ice formation and associated damage to your plumbing system.

Managing Hydrostatic Pressure

For in-ground pools, managing hydrostatic pressure is a critical safety consideration often overlooked by pool owners. Hydrostatic pressure is the upward force exerted by groundwater beneath your pool when the pool is mostly drained.

Before completely draining your pool or lowering water levels significantly, carefully remove hydrostatic plugs (also called hydrostatic relief valves) located at the main drain area one at a time. These plugs must be removed gradually and carefully to relieve pressure beneath the pool. Failing to do so can cause an in-ground pool to lift, crack, or buckle due to excessive ground pressure. Always check your pool’s specific design and manufacturer recommendations regarding hydrostatic relief procedures.

Important Safety Considerations

Never completely drain your pool unless absolutely necessary and specifically recommended by a professional. A fully drained pool can be susceptible to significant structural damage, including cracks in the pool shell, warping of vinyl liners, and damage to the pool’s framework. Additionally, completely drained pools may allow the structure to float or shift due to hydrostatic pressure from groundwater.

Always verify local regulations before beginning any draining process. Many municipalities have specific requirements about where pool water must be discharged due to chlorine content and environmental concerns. Never drain pool water into storm sewers without permission, as this violates many local codes.

Keep children and pets away from the draining pool and all equipment. Never leave pumps or other machinery running unattended. Ensure all electrical equipment is properly grounded and protected from water contact to prevent electrical hazards.

Frequently Asked Questions

Q: How often should I drain my pool?

A: Most pools only need complete or partial draining once per year, typically before winter. Partial draining may be necessary more frequently if water chemistry becomes unbalanced or debris accumulation is excessive.

Q: Can I drain my pool directly into my yard?

A: This depends on your local regulations and the chlorine level in your pool. Check with your municipal water department first. Most areas require chlorinated water to be directed to storm drains or other designated areas to prevent environmental damage.

Q: What should I do with the drained pool water?

A: Always direct pool water to a designated drainage area in compliance with local regulations. This typically includes storm drains, clean-out pipes, or designated discharge areas that comply with county health regulations.

Q: How long does it take to drain a pool?

A: Draining time varies depending on your pool’s size, the draining method used, and the equipment’s flow rate. Most pools take several hours to drain using a submersible pump, while siphoning may take longer.

Q: Can I leave my pool pump running overnight while draining?

A: While some pool owners do this, it’s not recommended. Unattended draining can lead to equipment damage if the pump begins sucking air or if water backs up unexpectedly.

Q: What happens if I drain my pool too quickly?

A: Draining too quickly can damage your pool’s main drain and plumbing lines. Aim for a safe drainage rate of approximately 12 inches per hour to prevent structural damage.

Q: Do I need a permit to drain my pool?

A: Requirements vary by location. Check with your municipal government or water department to determine if a permit is needed in your area.