How Often Should I Shock My Swimming Pool?

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Any pool owner will agree that installing a pool helps to improve health and lifestyle. To continue using that pool, safe and clean water is essential.

Keeping swimming pool water safe and sparkling requires regular maintenance and monitoring. Part of this process includes giving your pool the occasional dose of shock. 

In this post, we will show you what shock is, how often you should shock your swimming pool, and look at common circumstances that might require you to do it again. 

What Is Shock?

For those that are unsure, shock is a chemical used to eradicate any bacteria or organic contaminants found in your swimming pool.

The aim of shock chlorine is to dose your pool with the necessary amount of chemicals to destroy any bacteria and raise the chlorine levels in the pool to a better level when levels are running low. 

After using shock chlorine, you will have to wait at least 8 hours before entering the pool.

A nice alternative is a non-chlorine-based shock. Non-chlorine shock can be used as a supplement instead of normal pool chemicals.

When this supplement is used, swimmers can usually enter the pool again after approximately 15 minutes. 

Shock is important in pool maintenance because by destroying any bacteria or harmful organic contaminants, we can ensure swimmers have a safe swim without falling ill.

This is crucial if you are to keep your pool open and safe

How Often Should You Shock Your Swimming Pool?

Generally speaking, most swimming pool owners tend to shock their pools at least once every one to two weeks. They do this as regular pool management to ensure the pool is well maintained.

This is one of the best ways to prevent any algae growth and keep the chlorine levels nice and high. 

It is worth knowing though that this regular maintenance isn’t the only time it might be suitable to shock a swimming pool.

There are a host of other circumstances that can make it necessary to shock your pool (see also ‘Can You Shock A Pool Without The Pump Running?‘) again. Below you will find some of these common circumstances.


When you open your pool up for the first time in spring, it is always a good idea to first give it a good shock of chlorine to give the water a good boost.

This shock boost is the easiest and quickest way to raise the chlorine levels in the pool. If the chlorine levels in the pool are already adequate, you could use a non-chlorine shock instead.

This will help keep the swimming pool’s chlorine levels ticking over.


When you decide to close your swimming pool for the fall, you’ll be keen to make sure the chlorine levels are high enough to see the pool through the winter.

How Often Should I Shock My Swimming Pool?

If chlorine levels are low, a chlorine shock can be used. If chlorine levels are already at a suitable level, consider using a non-chlorine shock to help maintain those levels until after the winter.

After Extreme Weather

If your swimming pool is exposed to strong direct sunlight, windstorms, harsh heat, or heavy rain, chlorine levels will drop. This is because the chlorine levels will have dissipated faster than usual.

You will want to shock your pool as soon as possible to raise the chlorine levels once more.

The shock will quickly boost the chlorine levels to once again eliminate any organic contaminants or bacteria.

In this instance, you should add the shock at night. This will give the shock a chance to be active for longer without being destroyed by the sun.

After Heavy Usage

Every time people enter a swimming pool, they leave behind bacteria, skin cells, sun lotion, saliva, and sweat.

If you’ve entertained a lot of guests in your pool (maybe you’ve been lucky enough to host a pool party) there is a high chance chlorine levels will have dropped and bacteria levels will have increased. 

This increase in bacteria and decrease in chlorine levels calls for another dose of pool shock.

By adding pool shock after heavy usage, you can kill any leftover contaminants, and bring the chlorine levels back to where they should be.

Algae Growth

Algae growth inside the swimming pool is a clear sign that chlorine (see also ‘Raise Or Lower Level Of Pool Chlorine‘) levels have dropped. Surprise, surprise, that means you need to give the pool more shock.

While green algae is the most common type of algae, it can also grow in black, brown, yellow, or pink. If the algae is large in size, you might also need to use some algaecide in the pool too. 

Final Thoughts

Putting shock in your swimming pool is a sure-fire way to maintain healthy, bacteria-free water.

While most people shock their swimming once every one to two weeks, it is worth remembering the above circumstances.

In these circumstances, your pool could do with some extra shock to boost chlorine levels and maintain the pool’s ability to destroy bacteria and organic contaminants.

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