When it’s time to drain your pool — whether for cleaning, maintenance, repairs, or winterization — the process must be done with care. Draining a swimming pool might seem straightforward, but improper techniques can lead to severe damage to the pool structure, surrounding property, and local infrastructure. Without careful planning, you could encounter issues like structural damage, environmental concerns, and legal problems related to water disposal. This detailed guide will walk you through every step to ensure you drain your pool safely, efficiently, and responsibly.
Why Draining a Pool Can Be Risky
Before diving into the “how-to,” it’s important to understand why draining a pool is not a simple matter of opening a tap. Pools are not designed to be empty for long periods, especially if the water table in your area is high. An empty pool can float out of the ground — known as “hydrostatic uplift” — due to pressure from groundwater. This phenomenon can crack or distort the pool shell, leading to expensive repairs.
Additionally, discharging untreated pool water into municipal storm drains or natural waterways often violates local regulations. Pool water frequently contains chlorine, other chemicals, and sediment, which can harm aquatic life and public water systems. Understanding the risks associated with improper pool draining makes it clear that safety, environmental awareness, and local laws are critical.
When Should You Drain a Pool?
Draining your pool is not a routine task. It should only be done under specific circumstances:
Pool Repairs or Renovations
If you’re planning to tile, plaster, or repair cracks in the shell of your pool, partial or full draining may be necessary. Before you take this step, consult with a licensed pool contractor to determine the safest way to empty the pool while minimizing risk.
Major Algae Infestation or Contamination
In cases of extreme algae blooms or contamination, superchlorination may not be enough. Sometimes, the only way to restore water quality is to drain and thoroughly clean the pool.
Chemical Imbalance Beyond Repair
Very high levels of cyanuric acid, salt, or metals can make water unbalanced beyond correction without a partial or full drain.
Winterization in Freeze-Prone Regions
In cold climates, fully or partially draining a pool is part of proper winterization. However, this typically applies to above-ground pools or seasonal in-ground pools.
Gathering the Right Equipment
Before you proceed, gather and prepare all the equipment you’ll need:
Drainage Tools
- Submersible sump pump or high-capacity water pump
- Drain hose (ensure it’s long enough to reach the discharge point)
- Backwash hose (if using filter system)
- PVC pipe (for draining through plumbing, if applicable)
Protective Gear
- Rubber gloves
- Goggles
- Protective clothing
Water Testing Supplies
- Pool water test kit
- pH and chlorine testing strips
Step-by-Step Process: How to Drain a Pool Safely
1. Test and Neutralize Pool Water
Before draining any water, test for chlorine, pH, and salt levels. Chlorine should be below 0.1 ppm (parts per million) and pH should be between 6.5 and 8.0 for environmentally safe discharge. If necessary, use a dechlorinating agent (such as sodium thiosulfate) to neutralize chlorine.
2. Check Local Regulations on Water Disposal
Draining pool water into storm drains or sewers may violate local laws. Contact your local municipality to verify where treated pool water may be legally disposed of. For instance, some cities expect you to discharge into a sewer cleanout or septic system rather than directly into the environment. Failure to comply could result in hefty fines.
3. Choose the Right Drainage Method
There are three primary ways to drain a pool:
| Method | Pros | Cons |
|---|---|---|
| Using the filter system (backwash) | No extra tools needed; natural pressure helps speed up drainage | Slower; only drains until skimmer level |
| Submersible pump | Faster; can empty pool completely | Requires rental or purchase of pump |
| Drain plug or plumbing line | Safe and controlled if used correctly | Only applicable for in-ground pools with a main drain |
4. Locate the Ideal Discharge Point
Choose an area outside your yard where the water won’t negatively impact landscaping, hardscaping, or drainage systems. Never discharge water near your septic tank or into your neighbor’s yard. A grassy area, dry well, or municipal sewer cleanout are often the safest choices.
Avoid discharging pool water on:
- Cement or paved areas unsuitable for runoff
- Vicinity of garden beds or vegetable plots
- Storm drains or local waterways without permission
5. Start Draining the Pool
If you’re using a submersible pump:
- Turn off all pool equipment and circuit breakers.
- Place the pump at the deepest part of the pool, ensuring it won’t scrape the bottom and damage the plaster.
- Run a hose from the pump to the approved discharge point.
- Turn on the pump, and monitor water flow.
If using the filter system:
- Set the filter valve to “Backwash” or “Drain” position (check your filter’s instruction manual).
- Attach the backwash hose to the proper port.
- Run the hose to the discharge point and start the backwash process.
6. Monitor Temperature and Weather Conditions
On hot or dry days, water evaporates more quickly. Ensure that water is draining to a safe runoff point away from plant life and property. Also, if draining during heavy rain, groundwater may affect the pressure around the empty shell. Monitor the process closely.
7. Know How Much Water to Drain
Not all situations require a full drain. In many cases, partially draining the pool — just below the skimmer intake and return jets — is enough for maintenance or cleaning. This helps prevent the pool from floating and reduces the overall time and effort involved.
In summary:
| Reason for Draining | Recommended Drain Depth |
|---|---|
| Chlorine imbalance | Partial drain (30–50%) |
| Algae cleanout | Partial or full, depending on severity |
| Plaster work or tile replacement | Full drain required |
| Winterization | Varies by system and climate |
8. Keep the Pool Clean During Draining
Once the water level drops, algae, dirt, and mineral deposits can rapidly accumulate on exposed surfaces. Try to clean the pool as draining progresses, or as soon as possible after the process. Use a wet vacuum or towel to remove debris and keep walls and floor clean for when you refill.
How to Prevent Structural Damage While Draining
One of the greatest risks involved in draining a pool is structural damage due to hydrostatic pressure and groundwater levels.
1. Check Groundwater Levels
In regions with high water tables, groundwater pressure can cause serious damage. If the surrounding ground is fully saturated, emptying a pool even partially can risk “floating” the structure. A cracked or lifted pool can become a costly problem.
2. Avoid Draining During Heavy Rain
If there’s been recent or expected heavy rainfall, postpone your drain until conditions improve. The combination of rain-soaked ground and an empty pool is a dangerous one.
3. Keep Some Water in the Pool if Necessary
Rather than fully drain the pool, leave a foot or two of water if the situation allows. If the pool must remain empty for a prolonged period in an area with a high water table, hire a professional to monitor and adjust accordingly.
4. Consult with a Licensed Pool Contractor
If you’re uncertain about the water table or your pool’s construction, seeking professional guidance before draining is strongly advised. Many pool professionals offer hydrostatic evaluation services specifically to avoid damage from unexpected draining situations.
Environmental and Water Disposal Concerns
When you drain a pool, the water must be treated like any other chemical-laden discharge. Never dispose of it directly into storm drains, rivers, or natural water bodies without proper treatment.
1. Discharge into a Sewer Cleanout
The safest and most legal disposal method is using your home’s sewer cleanout connection. Ensure that the hose is securely connected and water is disinfected before disposal. A sewer system is designed to treat and manage chemically treated water.
2. Use Vegetated Areas Safely
Grassed areas or porous soil can accept small volumes of treated pool water. However, avoid saturating a single area. Distribute the water widely if it’s heading to the ground.
3. Avoid Runoff Into Public Storm Drains
Many towns and cities fine homeowners who discharge pool water into storm drains. These systems feed directly into rivers, lakes, and other natural bodies of water. The chlorine and other contaminants in pool water harm aquatic life and violate environmental protection standards.
4. Filter or Treat Water First
If you don’t have a sewer access point, consider using a garden-friendly dechlorinator and letting water sit for 24–48 hours without chemical traces before disposal. Chlorine dissipates when exposed to sunlight and air, but it can take time.
How to Speed Up the Draining Process
Time is a crucial factor — especially if you’re working outside of your pool’s preferred schedule or during cold weather. The larger the pool, the longer the draining time.
Choose a High-Capacity Pump
A pump’s efficiency is measured in gallons per hour (GPH). The larger the GPH, the faster your pool will empty. Ensure your pump is both powerful enough and rated for prolonged use. Some models are designed specifically for high-volume drainage purposes.
Use Multiple Pumps If Possible
Homeowners with large, commercial, or competition-sized pools can benefit from using more than one pump simultaneously. This not only increases efficiency but also reduces the risk to structures from prolonged exposure.
Hose Placement Makes a Difference
Make sure the hose runs at a downward slope from the pool to the drainage point. Avoid kinks or elevated pathways that may block water flow or reduce pressure.
Maintain Clear Debris Pathways
Leaves, sand, or dirt can clog the pump or hose over time, reducing flow rate. Stirring up the water or manually sifting debris before draining helps keep your system efficient.
Post-Drain Maintenance
Even once the draining process is complete, your work isn’t over. Here’s what you need to do once the pool is substantially empty or completely drained.
1. Inspect and Clean Surfaces
Look for cracks, scratches, scale buildup, or any damage to coping, tile, or flooring. Scrub exposed surfaces with a pH-neutral cleaner to maintain aesthetics and integrity.
2. Check and Winterize Plumbing (If Applicable)
For pools that are drained seasonally for winter, it’s crucial to blow out the lines or use antifreeze appropriate for pool plumbing systems. Proper winterization prevents frozen pipes and equipment damage.
3. Store Equipment Safely
Turn off and securely store pool pumps, filters, chlorinators, and any skimmers. Protect them from moisture and cold weather using covers and storage bags.
4. Prepare for Refilling
Once maintenance or repairs are complete, prepare to refill your pool with clean water. Be mindful of your local water supply and usage limitations. Refill slowly and test water chemistry immediately after.
Common Mistakes to Avoid When Draining a Pool
Draining a pool improperly can lead to unnecessary issues. Whether you’re handling this yourself or hiring a professional, avoid these common mistakes:
1. Draining in the Wrong Season
Draining in peak summer heat or during heavy storm season can damage the pool structure. Choose a moderate-temperature day with low precipitation risk.
2. Draining Too Quickly
Rushing the process leads to poor water discharge and uneven pressure changes in the pool’s structure. Allow the pump to do the job naturally without forcing water or manually removing buckets.
3. Ignoring Water Table Concerns
For in-ground pools, checking the groundwater level is non-negotiable. Draining a pool blindly without knowing your area’s subsurface water dynamics can lead to catastrophic damage.
4. Flushing Treated Water Illegally
Disposing of chemically treated water without permission, especially into storm drains or irrigation systems, could be illegal and harmful. Always neutralize chlorine and check local laws.
5. Not Planning Repairs Ahead of Time
Draining a pool only to delay repairs means the structure is vulnerable. Ideally, plan to drain when repairs or maintenance tasks are ready to begin immediately after.
Conclusion: Draining Your Pool the Safe and Responsible Way
Draining a pool might be an unavoidable part of pool ownership, but it should never be taken lightly. By understanding the technical concerns, local regulations, and proper procedures, you can ensure your pool remains intact and functional for years to come. Always prioritize structure safety, environmental responsibility, and water quality throughout the draining process.
Whether you’re preparing for winter, conducting repairs, or deep cleaning, this guide equips you with the knowledge and tools to make your pool maintenance task efficient and safe. Remember: draining your pool isn’t just about emptying water — it’s about protecting your investment and the environment.
By following the best practices, using the right equipment, and staying informed about your property’s unique needs, you’ll avoid costly damages and ensure every drainage process goes smoothly.
Why is it important to drain a pool correctly?
Draining a swimming pool improperly can lead to serious structural damage, including the pool popping out of the ground due to water table pressure or collapsing under the weight of water if drained incorrectly. In addition, improper drainage can cause environmental harm by releasing untreated water with chemicals into local waterways or storm drains. This is why it’s crucial to follow safe and responsible draining practices that protect both your property and the environment.
Before draining, always consult local regulations to ensure you are complying with municipal guidelines regarding water disposal. Consider testing the pool water for chemical content and pH balance to determine if it needs treatment or dilution before release. Proper planning and understanding of your pool’s specific requirements can prevent costly repairs and legal issues, while promoting environmentally conscious practices.
Can I drain my pool into the street or storm drain?
In most areas, draining pool water into the street or storm drain is not recommended and may be illegal. Pool water typically contains chlorine, algaecides, and other chemicals that can harm aquatic life and disrupt local ecosystems. Storm drains often lead directly to rivers, lakes, or other natural water bodies without going through a treatment process, so discharging untreated pool water this way can have detrimental environmental consequences.
If you need to drain your pool, the best practice is to first dechlorinate the water using a commercial dechlorination product. Once the chlorine levels are safe and the pH is balanced, you can discharge the water into a sanitary sewer line or a landscaped area on your property where the ground can filter the water naturally. Always contact your local water authority or municipal office to confirm what the legal and environmentally responsible disposal methods are in your area.
How do I determine the best method to drain my in-ground pool?
The best method for draining an in-ground pool depends on several factors, including the pool’s construction material (e.g., concrete, vinyl, or fiberglass), the local water table, and seasonal weather conditions. For instance, draining a vinyl liner pool when the water table is high can result in “floating,” a condition where the empty pool is pushed out of the ground by underground pressure. Always assess these risks before beginning the draining process.
Additionally, it’s important to use the right equipment—such as a submersible pump or a dewatering pump—specifically designed for draining pools. If you’re uncertain about the best procedure for your pool type, consult a licensed pool professional. They can help ensure that your draining method doesn’t compromise the structural integrity of your pool or surrounding landscape.
How long does it take to drain a typical residential pool?
The time it takes to drain a residential pool varies widely depending on the size of the pool, the type of pump being used, and the discharge location. On average, a standard 15,000 to 20,000-gallon in-ground pool can take anywhere from 8 to 14 hours to fully drain using a quality sump pump rated at 2,000 to 3,000 gallons per hour. Above-ground pools are generally smaller and may take less time, though pump capacity and hose length will still affect the overall duration.
To ensure an efficient and safe draining process, maintain a clear hose path and avoid kinks or bends that could reduce water flow. If the draining process exceeds one day, monitor the weather and groundwater levels closely, especially with in-ground pools. It’s also essential to keep the area around the discharge point free of erosion-prone material by using splash blocks or directing the water flow responsibly.
What should I do to prepare my pool for draining?
Before draining your pool, shut off all pool equipment, including the pump, filter, heater, and any automation systems. Turn off the circuit breakers to avoid electrical hazards during the process. If you plan to clean or repair the pool after draining, gather the necessary tools and materials ahead of time, such as brushes, cleaners, and repair kits. Also, check with municipal authorities to ensure compliance with local guidelines for water disposal.
It’s equally important to assess the pool’s structural condition before fully emptying it. Cracks, stains, or worn surfaces should be noted and addressed before refilling. For in-ground pools, remove any ladders, diving boards, or removable steps. Ensure that the surrounding landscape and drainage area are ready to receive the water, and take steps to prevent soil erosion during discharge. Taking these precautions helps protect your pool and property while ensuring a smooth draining process.
Can I use a garden hose to drain my pool?
While it may seem convenient, using a garden hose to drain a pool through a simple siphoning method is generally inefficient and time-consuming. Siphoning requires a continuous water flow to start and maintain the process, which wastes water and may not meet local regulations for chemical discharge. Additionally, the flow rate of a garden hose is significantly lower than that of a dedicated pump, making it impractical for larger pools.
If you must use a garden hose, ensure it is heavy-duty and long enough to reach a safe discharge area, such as a sewer cleanout or a landscaped zone on your property where water can be absorbed without causing damage. Also, consider the chemical content of the water, and make sure you have taken steps to neutralize chlorine and adjust the pH before releasing it. Overall, using a proper drainage pump is a more effective, responsible, and environmentally friendly option for most pool owners.
What precautions should I take when draining a pool during winter?
Draining a pool during winter requires special attention due to the risk of freezing temperatures. If water remains in the plumbing lines or equipment, it can freeze and expand, causing cracks and costly damage. To prevent this, completely drain all water from the pump, filter, heater, and plumbing lines by using a blower or air compressor and then winterize them appropriately with pool antifreeze.
If you are completely emptying the pool, it’s vital to ensure that the pool is not left vulnerable to ice damage. For in-ground pools, consult a professional about whether it’s necessary to leave some water in the pool or to install equalizer ports to prevent structural issues. Also, protect the pool cover and surrounding area from excess water accumulation, which can freeze and cause damage. Taking these steps will help maintain your pool throughout the cold season without incurring unnecessary repairs.