How to Lower the Water Level in Your Pool Safely

Aim for the Middle of Your Skimmer Opening

The skimmer is the rectangular suction box set into the upper wall of your pool. Inside that box sits a small hinged flapper door called a weir gate. When your pool water sits at the right level, water spills gently over this flapper door, creating a steady surface pull that pulls floating leaves, pollen, and bugs directly into the basket before they sink.

If heavy rain or an open garden hose raises the water above the top edge of that suction box, the flapper door stays underwater or floats flat against the back. Without that gentle drop over the door, the surface skimming action stops completely. Water drifts into the opening with very little suction, and floating debris simply wanders past the box and settles on the bottom of the pool.

Leaving the water too high also creates a risk of overflowing into your yard, washing out landscaping, and eroding the soil beneath your patio or pool deck. On the other hand, lowering the water too far creates a worse problem. If the water drops below the bottom edge of the suction box, the pump begins pulling in air instead of water. This condition, known as dry-running, causes the pump motor to overheat and can melt the internal plastic fittings and shaft seals in just a few minutes.

Your target is simple: bring the waterline to exactly halfway or two-thirds up the mouth of the suction box. At that height, the flapper door has room to swing freely, surface skimming works at full strength, and the pump stays completely flooded with water.

Set Your Multiport Valve to Waste to Dump Water Fast

If your pool uses a sand filter or a diatomaceous earth (DE) filter, your equipment pad likely features a multiport valve. This is the large control lever mounted on the top or side of your filter tank with several labeled settings. Using the Waste setting is the quickest, most direct method to dump excess water from your pool.

1. Shut off the pool pump motor completely. Never move the control lever while the pump is running. Turning the handle while water is under pressure can rip or dislodge the internal rubber spider gasket, which leads to permanent leaks inside the valve.
2. Roll out your backwash discharge hose. If your filter is plumbed into a dedicated PVC drain line that runs to a sewer cleanout, make sure that line is clear. If you use a flexible blue backwash hose, roll it out flat toward a safe drainage area on your property, making sure there are no kinks or sharp bends along the run.
3. Depress the control lever and rotate it to Waste. Push down firmly on the handle to disengage the internal spring, then turn it until the pointer locks into the Waste notch. The Waste setting routes water directly from the pool pump out through the discharge pipe, completely bypassing the filter sand or grids. Do not choose the Backwash setting for this task. Backwash pushes water backward through the filter media to rinse away dirt, which agitates the filter bed unnecessarily when your only goal is lowering the water volume.
4. Turn the pump motor back on. Water will immediately surge through the discharge line. The pressure can cause flexible discharge hoses to jump, so verify that the open end stays anchored where you want it.
5. Stand by the pool and monitor the water height. A standard pool pump can move 40 to 80 gallons of water per minute. In an average inground pool, dropping the water level by two inches can take less than ten to fifteen minutes. Stay right beside the pool while the pump runs so you do not miss your mark.
6. Switch off the pump as soon as the water reaches the midpoint of the suction box. Once the waterline reaches the correct height, turn off the motor immediately to avoid pulling air.
7. Rotate the lever back to Filter. Push down on the handle, rotate it back to the normal Filter position, and turn the pump back on to restore standard circulation.

Open the Drain Valve on Your Cartridge Filter Line

Cartridge filter tanks do not have a multiport valve lever because cartridge elements do not use backwashing. Instead, the filter is cleaned by taking out the pleated fabric cartridges and rinsing them with a garden hose. To lower the water level on a cartridge system, you must use a dedicated plumbing drain valve or an auxiliary hose spigot.

Most cartridge filter installations include a threaded brass drain spigot or a 3-way diverter valve installed in the PVC pipe between the pump and the filter tank. You can use this plumbing port to bleed off water under pump pressure.

1. Turn off the pump at the breaker or switch. Make sure the equipment has fully shut down and the system pressure gauge drops to zero before you touch the plumbing.
2. Attach a standard garden hose to the threaded spigot. Thread the female end of a heavy-duty garden hose securely onto the spigot. Run the other end of the hose to an approved drain area, making sure the line sits flat on the ground.
3. Open the spigot valve. Turn the spigot handle counterclockwise to open the water pathway into your garden hose.
4. Turn the circulation pump back on. The pump will pull water from the pool and push a steady stream through the garden hose. Because a standard garden hose is much narrower than a two-inch backwash pipe, this process moves water more slowly than a multiport Waste line. It may take 30 to 45 minutes to drop the water an inch or two.
5. Watch the suction box opening closely. Keep an eye on both the pool waterline and the garden hose connection. If the hose connection starts spraying water near your pump motor, shut off the power immediately.
6. Turn off the pump and close the spigot. Once the water level reaches the halfway mark on the skimmer box, shut off the pump power. Turn the spigot handle clockwise until it is completely closed, disconnect your garden hose, and restart your pump for regular filtration.

If your cartridge filter does not have a threaded spigot in the plumbing, do not try to lower the water by removing the drain plug at the bottom of the filter tank while the pump is running. That plug sits under high pressure, and taking it out while the pump runs can cause injury, crack the tank base, or blow out internal parts. Tank drain plugs should only be removed for passive gravity draining when the entire system is completely powered off.

Use a Garden Hose Siphon or Utility Pump if You Lack a Drain Line

If you own an above-ground pool, have a cartridge setup without a drain spigot, or want to lower the water level without running your main pool equipment, you have two reliable options: an electric submersible utility pump or a natural garden hose siphon.

Option 1: Using a Submersible Utility Pump

A submersible utility pump is a small, portable pump that sits directly underwater and discharges through a standard garden hose. This is the safest way to lower water without putting any wear on your primary pool pump.

1. Place the utility pump in the pool. Set the pump on the top entry step, a shallow sun shelf, or hang it by a strong cord so the intake sits just an inch below your target waterline. Setting it on a shallow step prevents the pump from draining the pool too deep if you step away for a moment.
2. Attach a garden hose to the pump discharge outlet. Lead the hose to an approved drainage location in your yard or household cleanout.
3. Plug the pump into an outdoor GFCI outlet. A ground-fault circuit interrupter outlet with a weatherproof cover protects you from electrical shock. Never use damaged extension cords, and always keep all electrical plugs at least ten feet away from the water edge.
4. Monitor the water line. Let the utility pump run until the water drops to the midpoint of your suction box. Unplug the pump from the wall outlet before reaching into the pool to lift it out.

Option 2: Creating a Natural Garden Hose Siphon

A garden hose siphon uses gravity to pull water out of the pool without using any electricity or running your filtration equipment. Siphoning is quiet and completely free, but it only works if you have ground near your pool that sits lower than the pool water surface.

1. Submerge the entire garden hose in the pool. Lower the hose into the water hand-over-hand, pushing the air out as you go. Wait until air bubbles stop bubbling out of both ends so the entire hose is filled with water.
2. Seal one end of the hose with your thumb or a palm. While keeping that end underwater, press your thumb firmly over the opening to trap the water inside.
3. Pull the sealed end over the pool wall. Keep your thumb locked over the opening, drag that end of the hose across your yard to an area lower than the pool waterline, and drop it on the ground.
4. Release your thumb. Gravity will pull the water column downhill out of the hose, creating a steady suction that draws water from the pool.

If your pool walls are too tall to submerge the hose easily, you can start the siphon using an outdoor hose bib. Connect the hose to your house spigot, drop the other end into the pool, and turn the outdoor tap on for twenty seconds. Once water flows into the pool and all air pockets are pushed out, turn off the tap, quickly unscrew the hose from the house spigot, and drop that open end onto low ground. The water will immediately reverse direction and siphon out of the pool.

Watch the Water Line Closely to Protect Your Pump and Yard

Lowering pool water is a straightforward maintenance chore, but common oversights can lead to burned motors or property damage. Keep this checklist in mind before you open any valve:

• Never leave the pool pump unattended during drainage. A high-power pool pump moves water with incredible speed. If you walk inside to do chores, a ten-minute distraction can easily pull the water below the suction box, causing the pump to run dry. When a pump pulls in air, the moving parts lose lubrication, the shaft seal overheats, and the plastic strainer basket can warp and lose its seal.
• Direct drainage away from foundations and structures. Dumping hundreds of gallons of pool water directly next to your house can cause foundation settling or basement seepage. Direct the discharge toward an open lawn, a gravel drainage bed, or an approved sewer cleanout point.
• Check local municipal rules for discharge water. Many cities prohibit sending pool water directly into street gutters or storm sewers because storm drains flow straight into natural waterways without treatment. In many neighborhoods, pool water must be dechlorinated before discharge or routed directly into a sanitary sewer cleanout port.
• Recognize the difference between storm draining and winterizing. Dropping water a few inches after a heavy summer downpour is very different from prepping equipment for freezing temperatures. When closing your pool for the season, review specific guidance on how far to drain your pool for winter to avoid damaging pool covers, skimmer throats, or vinyl liners.
• Verify your water chemistry once the level is set. Heavy rainfall and tap water additions alter your pool balance by diluting cyanuric acid, calcium, and sanitizers while shifting your pH. Once you restore the proper water height, take time for checking your saltwater pool chemistry or measuring chlorine and pH levels in a traditional pool so you can rebalance your sanitizer promptly.

FAQs

Can I lower the pool water using the Backwash setting instead of Waste?

You should use the Waste setting rather than Backwash to lower your water level. The Backwash setting forces water backward through your sand or DE filter grids, which stirs up the internal media and can blow filter material out of the discharge line. The Waste setting bypasses the filter tank entirely, sending pool water straight out of the system without disturbing the filter bed.

How long does it take to lower pool water by two or three inches?

When using your primary pool pump on the Waste setting, dropping the water level by two to three inches typically takes between ten and twenty minutes. If you are using a garden hose attached to a cartridge filter spigot, expect it to take thirty to sixty minutes. Using a small submersible utility pump or a garden hose siphon takes considerably longer, often requiring two to four hours depending on pool surface area.

Will an overfilled pool cause structural damage to the walls?

An overfilled pool rarely damages solid concrete, fiberglass, or vinyl wall structures directly. The real danger comes from water spilling over the pool coping and washing out the surrounding soil, which can cause concrete decking to shift, sink, or crack over time. Water that stays above the suction box opening also halts surface skimming, leaving floating debris to sink and stain your pool floor.

What should I do if I accidentally drain the water below the skimmer box?

Shut off your circulation pump immediately to keep it from pulling air and burning out the motor. Place a garden hose into the pool to fill the water back up to the midpoint of the suction box. Once the water reaches the right height, open the clear lid on your pump strainer basket, fill the pot with water to prime the system, secure the lid, and restart your pump.