How To Drain My Pool: The Complete Step-by-Step Technical Guide

To drain a swimming pool safely, you must utilize a submersible utility pump routed directly to a designated municipal sanitary sewer cleanout while continuously monitoring local groundwater levels to prevent catastrophic hydrostatic lift. Avoid using your pool’s primary filtration pump to empty the vessel, as this risks drawing in air, losing prime, and destroying the expensive motor. Complete drainage should only occur when outdoor temperatures are consistently under 85°F (29°C) to protect the structural integrity of the exposed pool shell or vinyl liner.

Pre-Drainage Planning, Equipment, and Regulatory Checklist

Draining a pool is not as simple as pulling a plug. It requires precise planning to protect the local environment, comply with municipal water codes, and safeguard your pool's physical structure from shifting. Before turning on any pumps, you must gather the correct equipment and understand the mechanical parameters of your pool.

Essential Gear and Tool Checklist

• Submersible Utility Pump: Rated for at least 1,500 to 3,000 Gallons Per Hour (GPH). Do not use your pool's main circulation pump to drain the pool completely.
• Heavy-Duty Discharge Hose: A flat-laying hose (typically 1.5 to 2 inches in diameter) that is long enough to reach your designated municipal drainage point.
• Sewer Cleanout Adapter: To securely hook up your discharge hose to your home's sanitary sewer cleanout port if required by local ordinances.
• Garden Hose: Helpful for dilution, washing down the pool walls, and keeping the pump intake wet during the final drawdown.
• GFCI Extension Cord: A heavy-duty, outdoor-rated power cord to safely run the submersible pump.
• Hydrostatic Relief Key or T-Bar: A specialized tool to safely open the hydrostatic relief valve located at the bottom of concrete and plaster pools.

Mandatory Prerequisite Knowledge and Standards

• Local Discharge Regulations: Many municipalities strictly prohibit draining chlorinated, salt-treated, or chemically balanced pool water into storm drains or public streets because it harms aquatic ecosystems. You must locate your property's sanitary sewer cleanout (usually a plastic pipe with a screw-on cap near the home's foundation or front yard) or obtain a special permit for curb drainage.
• Hydrostatic Pressure Risks: High groundwater tables exert immense upward pressure on an empty pool structure. Concrete pools can float or "pop" out of the ground, while vinyl liners can bubble and fiberglass shells can buckle. Never drain a pool during or immediately after a heavy rainstorm.
• Temperature Limits: Only drain plaster or vinyl-lined pools on cool, overcast days. Temperatures above 85°F (29°C) can cause exposed plaster to crack, dry out, or delaminate, and can cause vinyl liners to shrink and lose their custom fit.

Estimated Project Benchmarks

• Estimated Budget: $50 to $150 if renting a submersible pump and purchasing hoses; $150 to $300 to buy a high-quality, reusable utility pump setup.
• Estimated Duration: 8 to 16 hours for an average 15,000 to 20,000-gallon pool, depending on the GPH rating of your pump.

Step-by-Step Pool Drainage Execution

Follow these precise mechanical steps to safely drain your inground or above-ground swimming pool without causing structural or mechanical damage.

Step 1: Turn Off All Pool System Power

Go to your pool's main electrical subpanel and shut off all circuit breakers associated with the pool system. This includes the main circulation pump, booster pumps, pool heater, salt chlorine generator, automated chemical feeders, and pool lights.

Warning: Running a pool circulation pump without water will draw air into the plumbing system, causing the pump to lose prime and rapidly overheat. This can melt the pump basket, deform internal impellers, damage the shaft seal, and destroy the motor. If you have a gas heater, wait at least 24 hours after shutting it off before draining any water to ensure the heat exchanger has cooled completely.

Step 2: Locate and Prepare Your Discharge Area

Identify where the water will flow. Check your local municipal codes to confirm whether you must drain into your home's sanitary sewer cleanout or if street gutter drainage is permitted. If using a sanitary cleanout, unscrew the cap. Ensure your discharge point can handle a continuous flow of 25 to 50 Gallons Per Minute (GPM) without backing up into your home's sinks, toilets, or showers.

Warning: Never drain pool water directly onto your lawn or garden if it has high levels of chlorine (above 1 ppm), high salt content, or low pH, as this will kill vegetation, ruin soil chemistry, and potentially flood your home's foundation.

Step 3: Set Up and Lower the Submersible Pump

Attach the lay-flat discharge hose to the output nozzle of the submersible pump. Secure the connection with an adjustable metal hose clamp to prevent it from blowing off under pressure. Lower the submersible pump into the deepest part of the pool, which is usually near the main drain. Ensure the power cord is long enough to reach a GFCI-protected outdoor outlet without tension. Do not drop the pump by its power cord; use an attached nylon utility rope instead to lower and raise the unit.

Step 4: Route the Discharge Hose

Run the discharge hose from the pool to your designated drainage point. Avoid sharp kinks, twists, or tight turns in the hose, as these restrictions reduce the flow rate and put unnecessary backpressure on the pump motor. If routing across a public sidewalk or driveway, place protective rubber ramps over the hose to prevent vehicles or pedestrians from crushing it.

Step 5: Activate the Pump and Monitor the Drawdown

Plug the pump into your GFCI outlet to begin the draining process. Once water begins discharging, walk the entire length of the hose to check for leaks, kinks, or blockages. Check the discharge point to ensure the sewer cleanout or gutter is swallowing the water at the same rate it is being pumped. Monitor the pool's water level hourly.

Warning: If you have a vinyl liner pool, stop draining when there is roughly 6 to 12 inches of water left in the shallow end unless you are replacing the liner. Retaining some water provides the necessary ballast to keep the liner stretched and secured against the pool shell.

Step 6: Open the Hydrostatic Relief Valve (Concrete Pools Only)

As the water level reaches the deep end floor, locate the hydrostatic relief valve (HRV) in the main drain pot or on the floor of the pool. Use your specialized T-bar tool to unscrew the plug. Opening this valve allows any built-up groundwater beneath the pool to seep up into the pool cavity safely, equalizing the pressure and preventing the concrete shell from lifting out of the ground.

Step 7: Clear Residual Water and Turn Off the Pump

Most submersible pumps cannot pump water down to the absolute floor; they typically leave 1/2 inch to 2 inches of standing water. Once the water level drops below the pump's intake, immediately unplug the unit to prevent it from running dry and burning out. Use a wet-dry utility vacuum, buckets, and towels to remove the remaining water from the deep end floor.

Pool Drainage Methods and Technical Specifications

Choosing the right drainage method depends on your pool's construction, water volume, and available equipment. The table below outlines the core metrics, risks, and ideal applications for the three primary draining techniques.

Managing Drainage Complications and Structural Risks

Draining a pool can lead to severe structural damage or equipment failures if environmental and mechanical conditions are ignored. Use these operational troubleshooting protocols to address common field issues.

Scenario A: The pool shell begins to lift or "pop" out of the surrounding ground

• Root Cause: Excess hydrostatic pressure from a high water table beneath the pool shell forces the entire concrete or fiberglass structure upward because the weight of the water inside the pool (which normally holds it down) has been removed.
• Actionable Fix: Immediately stop pumping water out. If possible, reverse the process and begin refilling the pool with fresh water to restore ballast weight. Locate and remove the hydrostatic relief valve plug at the bottom of the deep end to allow underground water to enter the pool and equalize pressure.

Scenario B: The submersible pump is running but not moving any water

• Root Cause: The pump has suffered an "air lock" (air trapped in the impeller chamber preventing a vacuum from forming) or the discharge hose is kinked or blocked.
• Actionable Fix: Unplug the pump from the electrical source. Submerge the pump completely at an angle to allow trapped air bubbles to escape the intake housing, then set it upright. Check the entire length of the discharge hose for kinks, twists, or internal blockages. Plug the pump back in to verify flow.

Scenario C: The vinyl liner of the pool is shifting, wrinkling, or pulling away from the walls

• Root Cause: Vinyl liners rely on the heavy weight of the pool water to hold them firmly against the concrete or sand shell structure. Removing too much water removes this tension, allowing the vinyl to shrink, shift, or pull out of its track.
• Actionable Fix: Stop draining immediately. Re-secure any loose liner sections back into the coping track. Immediately begin refilling the pool while using a high-volume vacuum (such as a liner vac or shop-vac inserted behind the liner) to pull a vacuum seal between the vinyl and the pool wall, smoothing out wrinkles as the pool fills.

Frequently Asked Questions

Can I drain my pool using my main pool pump?

No, you should not use your main pool pump to fully drain your pool. Pool filtration pumps are designed to draw water through the skimmers and main drain under flooded suction; once the water drops below the skimmer line, the pump will pull air, lose prime, run dry, and overheat, resulting in severe motor and plumbing damage.

How long does it take to drain a 15,000-gallon pool?

Using a standard 2,000 GPH (33 GPM) submersible utility pump, it will take approximately 7 to 10 hours to completely drain a 15,000-gallon pool. This duration can vary based on the length and diameter of your discharge hose, head lift height, and the pump's mechanical efficiency.

When is the safest time of year to drain my pool?

The safest time to drain a pool is during the mild, dry seasons of spring or autumn when daytime temperatures are consistently between 55°F and 80°F (13°C to 27°C). Avoid draining during hot summer months to protect plaster from cracking, and avoid rainy seasons when the groundwater table is high and risks popping the pool shell.

Do I need to drain my pool completely every winter?

No, you should never drain your pool completely for winterization. Doing so exposes the pool structure to freezing temperatures, soil shifting, and hydrostatic lift; instead, you should only lower the water level 4 to 6 inches below the skimmer mouth (for plaster pools) or below the return jets (for vinyl pools) to protect the tile line and plumbing.

Professional Pool Maintenance and Drainage Services

Draining a swimming pool carries inherent structural risks that can result in tens of thousands of dollars in property damage if executed improperly. If you are dealing with high groundwater tables, complex hydrostatic relief valves, or if you feel uncomfortable handling high-volume pumping equipment, contact local certified pool professionals to execute the drain and refill process safely.