How to Safely Drain an Inground Pool—In Five Steps

Well, here we are. As you probably know, it’s never ideal to have to drain your inground pool. Chances are, you have a pool because you love a clean, refreshing swim—not because you wanted your own personal skate park. And after all, once you drain your pool you’ll quickly need to refill it—and that costs. Talk about a bummer.

But for anyone who’s had a pool for long enough, the time to drain will come. This isn’t a weekly, monthly, or even yearly process, and that’s a good thing. You can reasonably expect to need to drain your pool every few years. But when this rare event happens, it needs to be done just right—especially since your inground pool could get seriously wrecked if drained willy-nilly. I’ll explain when to drain your pool, how to drain it, and how to refill the water back up again. And again, time is of the essence—so let’s get started.

Why Would You Need to Drain a Swimming Pool? 

Since draining your pool is an event that should only really be necessary every few years, there are only a few situations that require it. If the below doesn’t apply to you, think twice about whether this is really a task you need to do. Hey, I’m all for saving you time and money whenever I can—and hello, this is one of those cases.

how to safely drain an inground pool

To Reset the Water

Let’s say your water’s chemical balance has gotten so out of hand that you’re ready to let it go and start anew. That makes sense, and it happens to everyone. Sure, your water has probably been sitting in your pool for quite some time—but that’s why we add sanitizer like chlorine and other chemicals.

However, there is one element to consider that can’t just be blasted away with what you add to your pool: the remnants of these chemicals, combined with dirt, debris, and other contaminants. These are called the total dissolved solids (TDS), and once they build up over a long period of time, they can seriously interfere with your water’s chemistry. 

You can monitor your TDS with a digital meter or test strips. Once it’s at about 2,5000 parts per million (ppm), it’s time to give your pool a much needed drain—and start fresh.

One necessary ticket to chemical balance is optimal circulation. Try the 1.5 HP Variable Speed Blue Torrent Thunder In-Ground Swimming Pool Pump—it pays itself off with energy saved in under a year, is eligible for rebates, and also comes with a lifetime warranty. As customer Eric D says, “Day one, I fired this pump up and it ran clean and fast.”

For Pool Maintenance 

Most of the maintenance we routinely do for our pools can be done with water still in it. It would be unreasonable, for instance, if a high-performance robotic pool cleaner couldn’t come in contact with water. But sometimes, one-off maintenance requires an empty pool. This includes everything from cleaning extreme metal stains and calcium deposits, to repairing the pool’s cracked floor, to repainting the bottom of your pool. Listen, you’ve got to do what you’ve got to do. And if you need to drain the pool in order to do it, keep reading on.

Five-Step Checklist: When to Drain Your Pool

First of all, I present you with the golden rule of draining your pool: make it quick! You do not want a pool sitting empty for any significant time. My cap? Make sure it’s no longer than one week. Go ahead and follow the checklist below to make sure you’re not in over your head when you do start to drain your pool.

1.     When You’re Ready to Pay the Bill

I hate to say it, but this isn’t going to be cheap—I mean, it can be up to 20,000 gallons you’re draining and replacing. Eek! You’d better budget ahead for that month’s water bill.

2.     When You Have the Time

Again, you don’t want to let your empty pool six for more than a week, max. But you’ll also need a significant amount of time during the draining process, because it’s never a good idea to run errands while you’re moving thousands of gallons of water. My guess is that it’ll take upwards of eight hours to drain completely—and can last up to sixteen. And filling it? That’ll take just as long. Womp womp.

3.     On a Sunny Day—But Not a Scorcher!

The last thing you’d want to do is do this job in the pouring rain, but don’t think you’re in the clear just because the sun’s out. That hot sunshine can seriously wreck your pool. Drain it during a heat wave and you’re and you can see damage anywhere from pool liner damage to cracked pool walls and floors. Make sure your empty pool is never left sitting in heat about 85 degrees Fahrenheit, 29 degrees Celsius. 

4.     After Your Chemical Levels Are Down

Finally, you can take a break on treating your water. Bet you never thought you’d hear me say that! The truth is, it’s probably required by your city that the water you drain doesn’t have high concentrations of pool chemicals. Before draining your pool, use test strips to make sure that your water is chlorine neutral, has a neutral pH, and doesn’t have high traces of other chemicals. For the exact levels required, contact your local water authority. 

how to safely drain an inground pool

5.     Once Your Circulation System is Prepped 

Automatic timers off! Imagine your pump comes on at any point during the draining process, pulls in air instead of water, and overheats—sometimes, this will even make pumps melt. No, thanks. And imagine your pool lights come on at 7:00 to an empty pool, heat up, and shatter. Now stop imagining and make sure your system is off—seriously, off.

Once your pool drains, you might find that it wasn’t as clean as you thought. To properly maintain sparkingly pool floors and walls—without hurting yourself in the process—try the patented 360-Degree Bristles Black & Decker Pool Brush. It was developed by long-term pool professionals to eliminate the hip and back pain associated with one-sided brushes.

Seriously: Avoid the Inground Pool Pop!

I know it’s tempting to skip to the part about how to drain your pool, instead of all these precautions. What could go wrong, right? Well, a lot. The worst of it is called pool pop ups, which is just what it sounds like: the bottom of the pool comes floating up, the PVC pipes underneath crack or separate, and the pool shell itself cracks. When this happens, the top edge of the pool also cracks or comes loose, the concrete decks around the pool get damaged, and the electric wiring going to the pool lights becomes damaged, which can be a major risk for electrocution. Yes, electrocution. 

Oh, and homeowners insurance? It rarely covers the damage. Yeah, we really don’t want this to happen to your pool. The safest way to ensure that the pool pop up doesn’t happen to you is to hire a professional to drain your pool—especially if you’re at high risk, such as if your location has a high water table (meaning water saturates a shallow layer of your particular area’s ground without sinking further), or if it has recently rained. Otherwise, the tips below should help you avoid this particular nightmare.

Know Where You’re Going to Drain

Before you start draining your pool, you absolutely need to have a game plan. Remember, this is thousands of gallons of water you’re about to move—and it’s got to go somewhere. Plus, your yard is not an option, and not just because you don’t want chemically-treated water going into your grass. Pool pop ups happen most frequently when there is pressure underground around your pool. Introduce water to the ground near your pool and you’re probably going to regret it.

So where should all that water go? Again, this is a time when you should consult with your local water authority. The usual process is to direct the water into one of your home’s sewer cleanouts, but some cities allow you to drain into the street—and others have tight restrictions on when you can drain your pool. Go to your local dot gov to find out the regulations that apply for you.

To take extra measures to avoid the pool pop up, make sure your drainage hose is long enough to reach the sewer cleanout (or wherever your local authority asks you to drain your water). And just in case any other drainage problems occur, direct the drainage hose downhill from the pool. You never quite know if your sewer cleanout is significantly clogged until you’re trying to push thousands of gallons of water through. If something goes wrong and that water happens to come back toward you, you want to make sure it’s nowhere near your pool.

Don’t forget that your pool pump is the heart of your circulation system—the right one will not only keep you from needing to drain your pool again anytime soon, but it’ll also help you save big. The Blue Torrent 2 HP Variable-Speed Pump is ultra-powerful, comes with a lifetime warranty, eligible for rebates, and pays itself off in under a year by energy saved. As customer Bill Britton says, “Runs great. Super quiet.” 

how to safely drain an inground pool

If There’s Been Rain, Wait

Stormy week? If you were ever curious about the absolute worst time to drain your pool, this is it. Because the rain has recently sunk into your yard, there is more pressure on the sides of your pool, and an increased risk that the ground will push the pool to pop out as the water empties.

Give the ground a few weeks to dry out before you attempt to drain your pool. While the ground itself might look dry, you never know what’s happening under the surface—and a pool pop-up is one mean way to find out.

Get to Know Your Relief Valves

Get ready for some jargon, but I promise it won’t last: the hydrostatic pressure relief valves of your pool are essential to preventing a pop up—and if this is your first time draining, you might not even be aware that you have them.

If you look at your pool’s floor, you’ll see one or more white rings plastered in place. Under that plaster, they’re threaded into a slotted pipe. That pipe runs along the floor of the pool and ends in an underground gravel pit that was put in place when the pool was originally built. These valves allow water that’s accumulated underground to come up into the pool when it’s drained. Without them, that inevitable underground water would create enough pressure to make your pool pop.

You’ll remove these rings once the pool is mostly drained to alleviate the pressure, but might want to have a few extra on hand just in case they get damaged during removal. When it comes to draining your pool, it’s always best to be prepared.

Now That We’re Ready, Let’s Get Draining—In Five Steps

You know the dangers and how to avoid them, so it’s time to seal the deal—without unsealing your pool’s floors and walls. Follow these steps to drain your pool as safely as possible. No doomsday scenarios here!

1.     Hook It Up: Install a Submersible Pump

Again, your regular pool pump isn’t going to cut it—it’s designed to suck in water, and once your pool drains even a little bit it’ll be sucking in air instead, which leads to a myriad of permanent damages. It’s better to rent or buy a submersible pump, which isn’t exactly cheap but won’t break the bank.

Making sure that the power cord is long enough to reach from the bottom of your pool to your outlet, place the submersible pump on the floor in the center of the deep end. It’s safer to avoid using an extension cord. The submersible pump will have a hose connected, and you’ll want to place the other end of that hose wherever you’re draining out all that water. Make sure that it reaches all the way, or you’ll have thousands of gallons of water gone rouge to deal with.

2.     The Moment We’ve Been Waiting For: Start Draining 

Turn on the submersible pump and start draining. You’ll want to stick around for this part, no matter how long it takes. Keep an eye on the cords and the hose to make sure that it’s all going smoothly—and keep a house flood from happening.

One task you can do while your pool is drained is switch over to saltwater, so that your chlorine is operating at the lowest, safest, and most consistent levels possible. Make a smooth transition with the Salt Ways Eco Friendly Salt Chlorine Generator. It’s ultra-reliable and comes with a lifetime warranty.

3.     Thanks for the Memories: Remove the Submersible Pump 

At a certain point, the water will be so low that the submersible pump is no longer pushing any of it out of your pool. That’s normal—very rarely do you need to drain every inch of water, and what’s left isn’t going to mess with your pool chemical balance in the future. Go ahead and turn off and remove your submersible pump. Anyway, it’s especially time for this next step.

4.     Open the Flood Gates—Or Just Your Relief Valves

It’s time to ease the pressure of that underground water. Make sure to open these hydrostatic pressure relief valves and keep your pool from popping up.

5.     Do What You Need to Do

If you drained the pool to fix the chemical balance, immediately proceed to these next steps. If you have work to do—such as repairing or painting your pool—go ahead and do that now. In the rare case that you need a totally dry floor to work, use a heavy-duty and durable cover pump like the Brute Force Pool Cover Pump. And as soon as you’re able—and in no more than one week—proceed to these next steps to refill your pool. 

how to safely drain an inground pool

How to Refill Your Pool—In Three Steps

A pool is designed to be full of water, so let’s get back to how things should be. Refilling is a lot more straightforward than draining, but it’ll still take some time—and you’ll need to rebalance your water from scratch. Just remember, it’ll all be worth it once you’re swimming again. 

1.     Replace the Relief Valves

Go ahead the restore those relief valves. You don’t want them open when you fill up your pool with water—that’ll drown out the gravel patch and create a thousands of gallons of weight of pressure. Tightly twist the plug into the valve with Teflon tape on the threads.

2.     Refill Your Pool and Turn on the Pump

Using one, or two, or three, or however many garden hoses you have, refill your pool. If your water source has a high concentration of metals, you’ll want to put a hose filter on each—or deal with ugly metal stains later, which might require you to drain your pool again. No, thanks.

3.     Balance Your Water 

Just like you would when you open your pool for the season, you’re going to want to balance your water from scratch. This is the toughest part of refilling your pool, but clean, sparkling, and safe waters will soon be the reward. 

That Must’ve Been Draining!

While the actual act of draining a pool doesn’t take too much muscle, the planning, and waiting, and waiting, can take it out of you. Now that your water is balanced, take a deep dive and relax. Everything is back to how it was meant to be. Enjoy.

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