Knowing how to drain a swimming pool safely helps you avoid common problems like pump damage, liner wrinkles, shell cracks, flooding, or improper water disposal. Whether you need to lower the water level, deep clean the pool, make repairs, or refresh old water, choosing the right draining method matters. In this guide, BlueStars Parts will walk you through when to drain your pool, how to choose the safest method, and what to do after refilling the pool so your equipment runs smoothly again..
Quick Diagnose
|
Symptom |
Possible cause |
Fix type |
|
The pool won't drain at all |
Clogged main drain, blocked submersible pump intake, or closed valve. |
DIY |
|
Draining is unusually slow |
Partially blocked discharge hose, low pump capacity, or debris restricting flow. |
DIY |
|
The pump runs, but no water moves |
The pump is running dry (water level too low), or the impeller is clogged. |
DIY |
|
Pump motor hums but won't start |
A weak or failed start/run capacitor is preventing the motor from reaching operating speed. |
DIY |
|
Pump overheats or shuts off quickly |
Faulty capacitor, blocked ventilation, or motor running too long without flow. |
DIY |
|
Water backs up or pools around the yard |
Discharge hose routed incorrectly; water is draining faster than the ground can absorb. |
DIY |
|
The pool shell cracks or pops up after draining |
Hydrostatic pressure from groundwater lifts an empty fiberglass or concrete shell. |
Professional |
|
Liner wrinkles or floats after draining |
Groundwater seeps under a vinyl liner when the pool is empty. |
Professional |
1. When Should You Drain a Swimming Pool?
There will come a time when you must drain the pool and replace it with fresh water. Here are the most common situations where draining your pool becomes necessary. However, before you decide to empty your pool, remember this golden rule: If you can still balance your water with chemicals, do NOT drain it yet.
-
High Total Dissolved Solids (TDS): Over time, sweat, sunscreen, dirt, and chemical residue accumulate. When the TDS level exceeds the acceptable limit (usually over 2500 - 3000 ppm), the water becomes "old" or "dead," rendering chemical treatments completely ineffective.
-
Elevated Cyanuric Acid (CYA) Levels: CYA protects chlorine from the sun's UV rays, but it does not evaporate. When CYA levels climb too high (typically above 100 ppm), it causes "chlorine lock," neutralizing the chlorine's sanitizing ability. The most effective way to reduce CYA is to partially or completely drain the water.
-
Excessive Calcium Hardness: When calcium levels in the water are too high, it leads to stubborn white scale buildup on the pool walls and plumbing, which can permanently damage your filtration and pumping equipment.
-
Major Repairs or Structural Renovations: You must drain the pool to perform physical maintenance, such as repainting the bottom, replastering, replacing mosaic tiles, or fixing severe leaks and cracks.
-
Severe Algae Infestation or Contamination: If a pool has been neglected for a long time, has deep-rooted black algae, or has turned into an unmanageable "swamp" where heavy chemical shocking fails, draining is often the only viable option.
-
Routine Maintenance (Every 3 to 5 Years): Even with impeccable pool care, industry experts recommend draining and replacing the pool water completely every 3 to 5 years to refresh the aquatic environment.
There will come a time when you must drain the pool and replace it with fresh water (Source: BlueStars Parts)
>>> Read more: How to Fix Green Pool Water: Causes & Easy Solutions
2. How to Choose the Right Pool Draining Method
There are three common DIY methods for draining pool water: using a submersible pump, creating a garden hose siphon, or using your pool pump on the waste setting. The best option depends on how much water you need to remove, what equipment you have, and how safely you can route the discharged water.
|
Method |
Ideal Situation |
Why it Works |
Key Caution |
|
Submersible Pump |
Full drains or large water removal jobs |
Works independently from the pool system and can remove water from low areas |
Use a GFCI outlet and turn it off before it runs dry |
|
Garden Hose Siphon |
Small above-ground pools or lowering water a few inches |
Uses gravity, no electricity required |
Very slow and only works if the drain area is lower than the pool water level |
|
Pool pump on waste setting |
Fast partial draining while water is above the skimmer |
Uses the pool’s existing pump to send water out through the waste line |
Do not let the pump pull air or run dry |
In conclusion:
-
Use a garden hose siphon if you only need to make minor adjustments to the water level, such as after a heavy rainstorm.
-
Use your pool pump if you need to quickly dump a moderate amount of water, provided your water level is high enough to keep the skimmer fully submerged.
-
Use a submersible pump for a complete pool drain. It is widely considered the most popular and safest DIY method overall because it operates independently from your pool's primary filtration system, eliminating the costly risk of burning out your main pool pump.
3. How to Drain a Pool With a Submersible Pump
Using a submersible pump is widely regarded as the safest and most effective way to completely drain a swimming pool, a process that typically takes a few hours. If you have decided this is the right method for your maintenance project, here is everything you need to know to execute the process safely and efficiently.
3.1 Tools and Safety Checks
Before you begin emptying your pool, it is crucial to gather the right equipment and ensure the working environment is safe. A submersible pump makes the job highly efficient, but because you are mixing electricity and large volumes of water, proper preparation is non-negotiable.
Tools:
-
A high-quality submersible pump capable of handling the volume of your pool.
-
A discharge hose that is long enough to reach from the deepest part of the pool to your drainage site.
-
A heavy-duty, waterproof extension cord if the pump's power cord cannot reach the outlet directly.
-
A sturdy nylon rope for lowering and lifting the pump.
Safety Checks:
-
Power Source: Ensure the pump is plugged into a Ground-Fault Circuit Interrupter (GFCI) outlet to prevent electrical shock.
-
Weather Conditions: Check the forecast to ensure there is no heavy rain, lightning, or extreme heat expected during the draining process.
-
Drainage Regulations: Verify your local city codes regarding where you can legally discharge chemically treated pool water
By taking a few minutes to prepare your tools and verify these safety protocols, you can prevent equipment damage, avoid local fines, and ensure a smooth, hazard-free draining process.
It is crucial to gather the right equipment and ensure the working environment is safe (Source: BlueStars Parts)
3.2 Step-by-Step Instructions
Once your tools are ready and the drainage area is confirmed, you can start setting up the submersible pump. Work slowly, keep the hose secure, and monitor the pump throughout the process to prevent overflow, electrical issues, or motor damage.
-
Attach the hose: Connect your discharge hose securely to the submersible pump, ensuring the threading is tight so no water leaks at the connection point.
-
Position the pump: Tie a sturdy rope to the pump's handle and gently lower it into the deepest part of the pool. Never use the power cord to lift or lower the pump, as this can damage the wiring.
-
Route the discharge line: Lay the discharge hose out flat to your designated, legal drainage area, making sure there are no kinks or sharp bends that could restrict water flow.
-
Turn on the power: Plug the pump directly into a GFCI-protected outlet to activate it and start the flow of water.
-
Monitor the process: Keep a close eye on the setup as the water level drops. Check the discharge hose for blockages and ensure the pump remains standing upright on the pool floor.
-
Turn it off promptly: Unplug the pump immediately once the water has been completely removed. Letting a submersible pump run dry will cause the motor to overheat and burn out quickly.
Tips: Drain the pool during mild weather when possible. Once the water level is low, use a pool brush to push shallow water toward the pump intake
What to monitor?
-
Water flow slowing: A sudden drop in the water discharge rate often indicates that a clog or debris is blocking the pump's intake.
-
Hose kinks: Sharp bends or folds in the discharge hose can severely restrict the water flow and cause dangerous back pressure.
-
Pump overheating: Submersible pumps rely on the surrounding water to keep their internal components cool during operation.
-
Unusual noise: Listen closely for any loud grinding, rattling, or high-pitched whining sounds coming from the motor.
Draining a pool with a submersible pump requires a secure hose setup and close monitoring to prevent clogs or pump overheating (Source: BlueStars Parts)
4. How to Drain a Pool With a Garden Hose
If you only need to remove a small amount of water, lower the level after a heavy rainstorm, or empty a small above-ground pool, using a garden hose to create a siphon is a highly practical method. Here is how to harness the natural power of gravity to effectively drain your pool.
4.1 Tools and Safety Checks
Setting up a garden hose siphon is remarkably simple, but you still need to ensure you have the right setup and a suitable environment for the water to drain properly. Since this method relies entirely on physics rather than mechanical power, preparation is key.
Tools:
-
A standard garden hose that is long enough to reach from the bottom of the pool to your drainage area.
-
A heavy, non-abrasive object, like a clean brick or a pool weight, to keep the hose submerged.
-
Access to an outdoor water spigot is optional, but helpful for priming the hose.
Safety Checks:
-
Elevation Requirements: Ensure your intended drainage destination is at a distinctly lower elevation than the pool's water surface, as the siphon effect relies completely on gravity to pull the water down.
-
Property Protection: Verify that the discharged water will flow away from your home’s foundation and will not flood your neighbor's property.
-
Chemical Runoff: Check your local regulations regarding pool water disposal. Ensure the chlorine or chemical levels are low enough so they won't kill your lawn or violate municipal codes.
Confirming these details beforehand ensures a steady, uninterrupted flow and prevents accidental flooding or landscaping damage in your yard.
4.2 Step-by-Step Instructions
Once you confirm that the drainage area is lower than the pool water level, you can start creating the siphon. The key is to keep the hose completely filled with water and prevent air from entering the line, since air pockets can stop the flow.
-
Submerge the entire hose: Place the whole garden hose directly into the pool, pushing it down so it fills completely with water. Ensure there are no air bubbles trapped inside, as air pockets will break the siphon.
-
Secure the intake end: Use your clean heavy object to pin one end of the hose securely to the deepest part of the pool. This prevents it from floating to the surface and sucking in air.
-
Seal the opposite end: While the other end is still underwater, cover the opening tightly with your thumb or kink the hose sharply so that no water can escape.
-
Position the discharge line: Keeping the end tightly sealed, pull it out of the pool and drag it over to your designated, lower-elevation drainage spot.
-
Release to start the flow: Remove your thumb or unkink the hose. As the trapped water drops out of the hose, gravity will create a vacuum that continuously pulls the rest of the water out of the pool.
Tips: To speed up the process, you can use two or three hoses at the same time. Check them regularly because siphoning can take several hours or longer.
What to monitor?
-
Water flow slowing or stopping entirely: If the water drops to a trickle or completely halts, it usually means air has entered the line and broken the vacuum seal.
-
Hose kinks: As the pool water level drops and the hose shifts position, it can easily fold or twist, which will immediately block the drainage.
Drain a pool with a garden hose step by step (Source: BlueStars Parts)
5. How to Drain a Pool Using a Pool Pump
Using your pool's built-in filtration pump is an incredibly fast and convenient way to lower the water level or perform a partial drain. Here is how to use your existing pool pump safely to drain water without ruining your equipment.
5.1 Tools and Safety Checks
Unlike other methods that require bringing in external equipment, utilizing your pool pump relies heavily on your existing plumbing. Your primary focus here will be on active monitoring and configuring the valves correctly, rather than gathering a lot of extra tools.
Tools:
-
A heavy-duty backwash or discharge hose (long enough to route water to your designated drainage area).
-
A hose clamp and a screwdriver to secure the discharge hose to the waste port tightly.
-
Access to your pool pump's multiport valve or push-pull valve system.
Safety Checks:
-
Water Level Limits: You can generally only drain the pool down to the bottom of the skimmer line. If the water drops below the intake and the pump pulls in air, it will lose prime and the motor will quickly overheat.
-
Drainage Destination: Ensure the discharged water is routed to an approved drainage area that can handle high-velocity water flow without flooding or eroding your yard's landscaping.
-
Valve Operations: Always ensure the pump is completely turned off before changing any settings on a multiport valve to prevent blowing out the internal O-rings or damaging the plumbing.
By verifying your valve settings and committing to keeping a close eye on the water level, you can harness the power of your pool pump without risking expensive damage to your filtration system.
Utilizing your pool pump relies heavily on your existing plumbing (Source: BlueStars Parts)
5.2 Step-by-Step Instructions
After confirming that the pump, valve, and discharge hose are ready, you can begin draining through the pool system. This method moves water quickly, so stay nearby and monitor the water level closely to prevent the pump from pulling air.
-
Turn off the power: Always shut off the pool pump completely at the breaker or power switch before adjusting any valves or connecting hoses.
-
Attach the discharge hose: Unroll your backwash or waste hose and connect it securely to the filter's waste port, tightening the clamp so the high water pressure doesn't blow it off.
-
Set the valve to 'Waste': Press down firmly on the handle of your multiport valve and rotate it to the "Waste" or "Drain" position. This completely bypasses the filter media, sending water directly out.
-
Route the hose: Lay the discharge hose completely flat to your legal drainage destination, ensuring there are no kinks or folds that could block the high-pressure water flow.
-
Turn on the pump: Restore power and turn the pump back on. Water should immediately begin flowing out of the discharge hose at a very rapid pace.
-
Monitor closely and shut off: Stand by the pump and watch the pool's water level constantly. The exact moment the water drops to the bottom of the skimmer intake and starts sucking air, turn the pump off immediately.
Tips: If your pool has a main drain and valves that allow skimmer suction to be shut off, you may be able to drain lower through the main drain. If you are not sure how your plumbing is set up, use a submersible pump instead.
What to monitor?
-
Water flow slowing: A sudden decrease in water volume usually points to a blockage in your skimmer, main drain, or pump basket.
-
Hose kinks: Since the pool pump forces water out at high pressure, any sharp bends or twists in the hose will create intense back-pressure.
-
Pump overheating: The pump's motor depends on a steady stream of water to stay cool while operating. If you notice the equipment becoming unusually hot to the touch, shut off the breaker immediately to avoid melting internal parts or completely burning out the motor.
-
Unusual noise: Loud gurgling or straining sounds are critical warning signs that the water level is too low and the pump is sucking in air.
Drain a pool using a pool pump step by step (Source: BlueStars Parts)
6. What to Do After Draining Your Pool
After draining the pool, the next steps are just as important as the draining process itself. Proper cleaning, refilling, and equipment checks help protect the pool structure and keep the water safe once the pool is back in use.
-
Inspect and Clean the Empty Shell: Take advantage of the drained pool to thoroughly pressure wash the walls, scrub the water-line tiles, and inspect the plaster, fiberglass, or vinyl liner for any cracks, damage, or wear that needs repairing before the new water goes in.
-
Refill the Pool: Drop your garden hoses into the deep end and turn on the water. Depending on your water pressure and pool size, this can take a day or two. Monitor the process closely and turn the water off once the level reaches the midpoint of your skimmer hatch.
-
Test and Rebalance the New Water: Fresh tap water is not ready for swimming. You must test the water and add a fresh round of chemicals, including chlorine, cyanuric acid (CYA), and calcium, to bring the pH, alkalinity, and sanitizer levels into the proper, safe ranges.
-
Run the Filtration System (24–48 hours): Once the pool is full and the initial chemicals have been added, prime your pump and turn it on. You must run your filtration system continuously for 24 to 48 hours. This prolonged circulation is vital to thoroughly mix the new chemicals, filter out any impurities from the municipal water line, and establish a healthy, balanced aquatic environment.
If the pump motor hums, struggles to start, shuts off quickly, or overheats after the pool is refilled, the start/run capacitor may be weak or failing. When this happens, installing a reliable replacement like the 97F9850 97F9970 50+5 uF/MFD 370 or 440 VAC Dual Run Circular Start Capacitor is a great solution. Upgrading to a high-quality dual-run capacitor will provide the precise burst of energy required to help your pool motor start reliably and run smoothly without overheating.
WARNING: Stop and call a professional immediately if you notice any of the following:
-
The pool structure shifts: If you hear popping sounds, see new massive cracks, or notice the concrete shell lifting, this is a severe hydrostatic pressure emergency.
-
The liner starts floating: If you have a vinyl pool and the liner begins to wrinkle, pull away from the walls, or float upward, groundwater is trapped underneath.
-
The water drains unevenly: If water pools in unusual spots instead of the deepest drain, or the pool shell appears tilted, the underlying foundation may be compromised.
97F9850 97F9970 50+5 uF/MFD 370 or 440 VAC Dual Run Circular Start Capacitor (Source: BlueStars Parts)
7. FAQs
7.1. How to empty a swimming pool without a pump?
You can drain a pool without a pump by using a siphon method with a garden hose. This works by filling the hose with water, placing one end in the pool and the other at a lower elevation, allowing gravity to pull the water out. While simple and inexpensive, this method is much slower than using a pump and works best for smaller pools or partial draining.
7.2. What setting should my pool pump be to drain water?
To drain water using a pool pump, the valve is typically set to “waste” or “drain”. This setting bypasses the filter and sends water directly out of the system, preventing debris from clogging the filter. Always ensure the pump is properly primed and monitored during draining to avoid running it dry or causing damage.
7.3. How long does draining a pool take?
The time required to drain a pool depends on its size, the pump’s power, and the drainage method used. With a standard pool pump, it can take anywhere from several hours to a full day to drain completely. Using a siphon hose may take significantly longer, sometimes over 24 hours, especially for larger pools.
7.4 Is it safe to fully drain a pool?
Fully draining a pool is generally not considered safe unless it is truly necessary. Removing all the water can cause structural damage, especially for in-ground pools, because groundwater pressure may crack or lift the pool shell. Vinyl and fiberglass pools can also warp or shrink when left empty. In most cases, partial draining is a safer option for maintenance or water treatment.
Draining your pool the right way is essential to protect your equipment and keep everything running efficiently long-term. By following proper steps for how to drain a swimming pool, you can avoid common issues like pump damage, air leaks, or poor water circulation after refilling. If you notice any performance issues, reliable replacement parts from BlueStars Parts can help restore your system quickly and keep your pool in top condition.
Contact information:
8 The Green, Ste A, Dover, Delaware 19901-3618, United States
Website: https://bluestarsparts.com/
Explore Related Articles
How to Fix Green Pool Water: Causes & Easy Solutions