What Happens If You Don’t Shock Your Pool? Pool Shocking Explained

Sometimes you may notice a strong smell in the pool. Or maybe your eyes start to burn after a short swim. That could mean the pool needs a shock.

Many pool owners think the water looks clean, so it's fine. But clear water doesn't always mean safe water. According to the CDC, many swimming pool illnesses come from bacteria that chlorine couldn't kill fast enough. Shocking helps fix that!

But many pool owners skip this step because they don’t know how, or they think it’s not needed.

Shocking a pool means adding a big dose of chlorine (or another chemical) to kill harmful stuff in the water. It helps your pool stay clean, safe, and healthy.

In this blog, we’ll explain:

• What shocking a pool means

• When to do it

• What happens if you don’t

• And how to shock the pool the right way

Let’s make pool care simple—and safe—for everyone!

What Happens If You Don’t Shock Your Pool?

What Is Pool Shocking?

Pool shocking might sound like something big or scary—but it’s actually pretty simple.

Shocking a pool just means adding a large dose of chlorine (or another strong sanitizer) to the water. This helps kill germs, bacteria, algae, and other harmful things that regular chlorine can’t handle on its own.

Why do we need it? Because over time, the chlorine in your pool gets weaker. Sunlight, swimmers, dirt, and even rain can break it down. That’s when your pool needs a boost—a shock!

Let’s break it down in easy terms:

• Free chlorine is the “good chlorine” that fights germs.

• Combined chlorine is the “used-up chlorine” that doesn’t work anymore—and causes that strong pool smell.

• Shocking gets rid of the bad chlorine and brings back the good.

It’s not dangerous when done the right way—and it helps keep your pool clean and safe.

When Should You Shock Your Pool?

There are some clear times when your pool needs a good shock. Here are the most common situations:

• After heavy pool use: If you had a pool party or lots of swimmers, there’s extra sweat, sunscreen, and even pee in the water.

• After a rainstorm or windy day: Rain and wind bring dirt, leaves, and germs into the pool.

• If the water smells strong or makes your skin/eyes burn: That’s a sign your chlorine is used up, and bad stuff is building up.

• If the water is cloudy or green: This could mean algae or bacteria are growing—shocking helps clear it up.

• Once a week in summer: Hot weather, more swimmers, and more germs mean your pool needs extra help.

Easy rule to remember: If in doubt, shock it out! It’s always better to be safe than sorry.

What Happens If You Don’t Shock Your Pool?

Skipping pool shocks might not seem like a big deal—but it can cause real problems fast.

Here’s what can go wrong:

• Water looks clean—but it’s not. Germs and bacteria can still be hiding in the water.

• Algae grows fast. Without shock, green slime can show up almost overnight.

• Chlorine gets weak. Over time, your regular chlorine can’t keep up. Shocking gives it a boost.

• Burning eyes and itchy skin. This happens when bad stuff builds up in the water.

• Strong pool smell. That “chlorine smell” is actually a sign your pool needs shocking.

• More money later. If you don’t shock your pool, you might need to spend more on chemicals or hire a pro to fix it.

You might think your pool is just fine… until your guests leave with red eyes, or you wake up to green, cloudy water.

How to Shock a Pool – Step-by-Step

Shocking your pool sounds hard—but it’s really easy if you follow these steps.

Step 1: Test the Water

Check your chlorine, pH, and other levels. Use test strips or a test kit. You will find the products in our store Perfect Pool Products.

Step 2: Pick Your Pool Shock

There are different kinds:

• Calcium hypochlorite (strong and common)

• Non-chlorine shock (gentler but still works well)

Choose what’s best for your pool type.

Step 3: Read the Label

Always read the directions on the shock bag. Use the right amount for your pool size.

But here’s a general rule that helps:

Use 1 pound (1 bag) of shock for every 10,000 gallons of water.

How to Figure Out How Much Shock You Need:

1. Find out how much water your pool holds.

• Small pool (12ft round above ground): around 5,000 gallons

• Medium pool (15-18ft round): about 8,000–10,000 gallons

• Large pool (20x40ft in-ground): about 30,000 gallons

2. Use this formula:

Gallons ÷ 10,000 = Number of 1lb shock bags

Examples:

• 8,000 gallons ➡️ 8,000 ÷ 10,000 = 0.8 bags → use just under 1 full bag

• 20,000 gallons ➡️ 20,000 ÷ 10,000 = 2 bags

• 30,000 gallons ➡️ 30,000 ÷ 10,000 = 3 bags

Tip: Always round up if your pool is dirty or cloudy. It’s better to shock a little more than too little.

Step 4: Add Shock in the Evening

Why at night? Because sunlight burns off chlorine. Evening shocking = more power, better results.

Step 5: Run the Pump

Turn on your pool pump and let it run for at least 8 hours. This helps mix the shock and clean the water.

Step 6: Wait Before You Swim

Check the chlorine levels before jumping in. Wait until the levels are safe (usually below 3 ppm).

Note: Always wear gloves and eye protection when handling shock. It’s strong stuff!

How Long Does It Take to Shock a Pool?

Shocking a pool doesn’t take long to do, but it takes time to work.

• It takes about 15 minutes to mix and pour the shock into the pool.

• Then, you need to run the pool pump for 8 hours or more to spread the shock around.

• Don’t swim right away! You need to wait until chlorine levels go down to a safe level. Use a test kit to check—it should be 1–3 ppm before swimming again.

How Often Should You Shock Your Pool?

Keeping a clean pool is like brushing your teeth—you need to do it often!

Here’s when to shock:

• Once a week during summer (when it’s hot and you use the pool more)

• After rain, storms, or lots of wind (dirt and stuff gets in)

• After a party or heavy swimming (more people = more germs)

• If it smells bad or looks cloudy (that’s a sign it needs help)

• Once a month in winter or when the pool isn’t used much

Conclusion

Shocking your pool is not hard—but it’s a big part of keeping your water clean and safe. If you skip it, you could end up with green water, itchy skin, or costly fixes later.

Check out our best-selling pool shock and test kits to make the job easy.

And if you found this helpful, share it with your friends, family, or neighbors who have a pool. Let’s keep every pool clean and clear!