Submersible Pump on a Pool Cover: How to Remove Water Without Damage

You step outside after a week of rain and find your pool cover holding what looks like a small pond. It’s sagging in the middle, the edges are pulling against the anchor straps, and something is floating in there that you’d rather not identify. If that scene is familiar, you already know the pressure to fix it fast.

The right tool for this job is a submersible pool cover pump – a compact unit you set directly on the cover that drains standing water without you having to scoop, siphon, or guess. The short answer: place the pump at the lowest point of the cover, attach a discharge hose routed away from the pool, and run it until about 1/4 inch of water remains. This article walks through every step in order, covers the equipment choices, flags the mistakes that tear covers or ruin pumps, and explains where the water should actually go.

Why Standing Water on a Pool Cover Is a Real Problem

A single inch of water across a 16×32-foot cover weighs roughly 665 pounds. Two inches doubles that. That kind of load does three things: it stretches and eventually tears the cover material, it puts dangerous stress on anchor straps and water bags, and on tarp-style covers it creates a trampoline effect where the center sags until it touches the pool surface below. Once the cover sags into contact with the pool water, debris and contaminated runoff can mix directly with what you worked hard to balance before closing.

As A-1 Pools explains, tarp-style winter covers are especially vulnerable because they lack the rigid structure of a safety cover – even modest water accumulation can accelerate wear and shorten the cover’s lifespan from 5-7 years down to 2-3. Removing water before it reaches 2 inches deep is the threshold worth keeping in mind.

Choosing the Right Submersible Pump

Not every submersible pump belongs on a pool cover. A standard basement sump pump rated at 1,500 GPH or more creates strong suction that can pull a lightweight cover inward and fold it around the pump. A dedicated pool cover pump rated between 250 and 500 GPH is the right range for most residential pools.

Pool Cover Size	Recommended Pump Capacity	Estimated Drain Time (6 inches of water)	Automatic Float Switch?
Up to 15×30 ft (above-ground)	250 GPH	About 60-90 minutes	Optional but helpful
16×32 to 18×36 ft (inground)	350 GPH	About 90-120 minutes	Recommended
20×40 ft and larger (inground)	500 GPH	About 90-120 minutes	Strongly recommended

Why These Differences Matter

Undersized pumps struggle to keep up with heavy rainfall and may run continuously without clearing the water fast enough to prevent cover stress. Oversized pumps move water so aggressively that the cover fabric can be pulled toward the pump’s intake and damaged. An automatic pump with a float switch is worth the extra $15-30 because it turns itself on when water reaches about 2 inches and shuts off before the cover runs completely dry – which protects both the pump and the cover material.

Step-by-Step: How to Pump Water Off Your Pool Cover

1. Clear debris first. Before you set the pump down, pull off any leaves, branches, or heavy debris from the cover surface. A single stick under the pump base can puncture a thin tarp cover. Use a leaf blower on a low setting or a soft pool brush – not a rake.
2. Find the lowest point. Walk around the pool edge and look for where the water is deepest. That’s where you’ll place the pump. On most sagging covers, it’s near the center.
3. Set the pump flat on the cover. Lower it gently – don’t drop it. Make sure the pump sits flat and the intake screen faces down. If your pump has rubber feet, confirm they’re making contact with the cover, not balanced on a wrinkle.
4. Attach and route the discharge hose. Connect the hose to the pump’s outlet port and run it at least 10 feet away from the pool. Direct it to a lawn area, a drain, or a garden bed – but not back toward the pool. Cover water typically carries debris, bird droppings, tannins, and early algae growth. You do not want it back in your pool.
5. Plug in and monitor. Plug the pump into a GFCI-protected outdoor outlet. Watch the first few minutes to confirm water is actually moving through the hose. If you see the hose go limp, the pump may have lost prime – lift it slightly and reset it.
6. Stop at 1/4 inch of remaining water. Do not run the pump until the cover is bone dry. A thin film of water left behind actually protects the cover material from UV and keeps the pump from running hot. If you have an automatic pump, the float switch handles this cutoff for you.
7. Remove and store the pump. Once done, disconnect the hose, pull the pump off the cover, rinse it with clean water, and store it indoors. Cover pumps left on the cover through winter often freeze and crack their housings.

For a visual walkthrough of this process from setup to finish, PoolPartsToGo’s guide on using a submersible pool cover pump covers the key steps clearly and is worth a quick read before your first attempt.

Common Mistakes That Damage Covers (and Pumps)

• Pumping completely dry: Running the pump until no water remains means it runs hot and risks burning out the motor. It also lets the cover pucker and shift without the water weight holding it in position.
• Using a sump pump instead of a cover pump: Basement sump pumps often draw 1,200 to 2,000 GPH and can create enough suction to collapse a lightweight cover around the intake. Stick to a unit rated for pool cover use.
• Skipping debris removal: A single sharp stick or acorn trapped under the pump base acts like a punch tool on thin vinyl or mesh covers. Always clear the surface first.
• Routing discharge water back into the pool: Cover water often contains organic debris that consumes chlorine and raises phosphate levels. Running it into the pool means extra shocking work in spring – and possibly a green pool before you even open.
• Leaving the pump on the cover all winter: Freezing temperatures crack pump housings and can lock the impeller. Bring the pump inside after every use, or at minimum before a hard freeze.

Good fall prep also reduces how much water ends up on the cover in the first place. If you haven’t already reviewed your pre-closing checklist, the guide on fall pool maintenance before you close covers the steps that make spring opening much easier.

Where Should the Water Actually Go?

Routing discharge water correctly is more important than most people realize. Dump it into a storm drain if your municipality allows it – call your local public works office if you’re unsure, because some areas prohibit draining pool-adjacent water into storm systems. A lawn or garden bed at least 10 feet from the pool is a safe default: the organic material in cover water actually provides a mild nutrient boost to grass.

Avoid directing discharge water toward your pool equipment pad, your pool’s return jets, or any area where it can flow back into the pool. And if you’re using a product like AquaDoc’s pool cover treatment to suppress algae growth under the cover, the discharge water from a treated cover is safe for lawn use – just keep it well away from vegetable gardens where chemical concentrations could affect edible plants.

For more on managing cover water chemistry and alternative removal methods, Crystal Pools’ overview of removing water from a pool cover and Kendisco’s breakdown of pool cover pump setup are both practical references worth bookmarking.

How Often Should You Do This?

Check your cover after every significant rain – anything over half an inch of precipitation. In regions with heavy fall and winter rainfall, that could mean weekly checks from October through March. If you have a solid safety cover with an automatic pump set to a float switch, the pump handles it automatically and you just need to verify it’s working during your checks.

For tarp-style covers without an automatic pump, the 2-inch rule is your guide: as soon as standing water reaches 2 inches deep anywhere on the cover, it’s time to pump. At that depth on a 16×32 cover, you’re already dealing with roughly 600 pounds of water stress. As HomeGnome’s pool cover care guide points out, consistent removal – not just occasional draining – is what actually extends cover life.

Frequently Asked Questions

How do I use a submersible pump to remove water from a pool cover?

Place the pump at the lowest point of the standing water on the cover, connect a discharge hose routed at least 10 feet away from the pool, and run it until about 1/4 inch of water remains. Most cover pumps rated 250 to 500 GPH will clear a typical 150 to 300-gallon load in 60 to 90 minutes. Stop before the cover runs completely dry to protect the pump motor and prevent the cover from shifting.

Can a submersible pump damage a pool cover?

Yes, if you use the wrong pump or skip debris removal first. An oversized sump pump rated over 1,000 GPH can create enough suction to pull lightweight cover material toward the intake and tear it. Sharp debris trapped beneath the pump’s base can also puncture thin vinyl covers. Always clear the surface before placing the pump and use a unit specifically rated for pool cover use.

What size submersible pump do I need for a pool cover?

For above-ground pools with covers up to 15×30 feet, a 250 GPH pump is sufficient. For inground covers in the 16×36-foot range, use 350 GPH. Large inground covers at 20×40 feet or bigger benefit from a 500 GPH automatic unit with a float switch. Anything above 500 GPH risks cover damage through excessive suction on standard tarp or mesh material.

How often should you pump water off a pool cover?

Remove standing water whenever it reaches 2 inches deep, or after any rain event exceeding half an inch. On a 16×32 cover, 2 inches of water adds roughly 600 pounds of stress to the cover and anchor straps. An automatic pump with a float switch handles this continuously, which is the easiest solution for pools in rainy climates.

Should you pump pool cover water into the pool or away from it?

Always route discharge water away from the pool – at least 10 feet from the edge. Cover water accumulates debris, bird droppings, algae spores, and tannins over the winter. Adding it back to the pool increases your spring chemical load significantly and can contribute to an early algae bloom before you’ve even removed the cover.

The bottom line: a 250 to 500 GPH submersible pump placed flat on a debris-free cover, with discharge routed away from the pool, is the fastest and safest way to clear standing water without damaging your cover. Check after every half-inch of rain, stop pumping at 1/4 inch remaining, and store the pump indoors before any freeze.