How Often To Shock Pool

Shocking your pool – treating it with a product that increases the chlorine content up to 5 times the norm for safe swimming – is an essential part of your pool maintenance regime.


Because your pool is full of water, but it’s also open to the elements, exposed to the air and the UV rays of the sun, and, let’s not forget, it’s also frequently full of people.

How long after shocking pool can you swim?

People who wear oils, and moisturizers, and all manner of other chemical preparations on their skin before taking a dip.

What happens to a normal swimming pool over time is that it begins to grow microbes, and algae, and the chemicals we smear onto our bodies before going into the pool also leach out into the water, resulting in a kind of chemical soup that – unless both cleaned and shocked – will quickly lead to people being unwell after taking a dip.

Remember, shocking is not the same as cleaning. You should clean your pool regularly too, but shocking is a more intensive treatment.

Pool shocking is kind of like an atom bomb – it will kill everything you don’t want living in your pool down to the microbial level, and it will clear the water of all the chemicals we dissolve in it, too.

So, how often should you drop your chlorine atom bomb?

That’s where things get interesting, because there are two schedules at work with pool shocking.

On the one hand, there’s standard “whether it needs it or not” shocking (It will inevitably need it, in case you’re wondering).

And then there’s the incident-based need for shocking, where you shock in response to one of a handful of known events.

There’s a little debate in pool shocking circles as to when the ideal schedule is for standard, regular shocking.

Some say you should shock your pool once every week.

Some maintain you can get away with shocking your pool once every two weeks.

No-one, as far as we know, is the kind of wild-eyed friend of bacteria that suggests you leave it three weeks or more.

And on the off-chance that you meet such a person, you might think twice about shaking their hand.

So, what we have then is a process that can be left for at most two weeks before you do it if you intend to have a swimming pool that’s safe to swim in.

Shocking your pool is relatively simple to do. Check out our Best Pool Shock article to find the pool shock that works best for you.

Wait until the sun goes down (because pool shock is significantly less effective when exposed to the sun’s UV rays). 

Make sure your pool pump is running. This feels like it shouldn’t need saying, but you never know: on no account shock your pool when there are people in it.

You remember that thing about it being like an atom bomb, like it killing lots of things in your pool?

It can be absurdly dangerous to human health to suddenly ramp up the chlorine levels in contact with the body. Never, ever do this.

Use two pounds of shock for every 10,000 gallons of water in your pool.

That’s the sort of quantity you’re looking to use (which is why pool shock is so often sold in convenient 1 pound containers). 

By making sure your pool pump is running, you’re ensuring that the shock will get everywhere in the pool.

Do not swim in your pool for at least 24, and ideally 48 hours after you shock your pool. At least, do not swim in it if you like having skin and eyes that work as well as you’ve become used to.

The 48 hour period will allow the chemicals in the shock to pass through the pool and return the chlorine levels to a point where you can swim safely.

Always check the packaging for the precise recommended wait times for the pool shock you choose.

Got it? Done it? Great – your pool should be low enough in algae and microbes for the next two weeks.


Remember that second schedule we mentioned?

How long after shocking pool can you swim?

Yeah. There will be times in between your regular two-week shockings. If any of these things happen – shock the pool. It’s in your best interests.

1. It’s The Start Of The Season

You’d make sure any other thing you owned was fit and ready for action after having been covered for the winter or simply not used in a while.

If you’d like to dip your body in a pool that hasn’t been used all winter before doing anything to kill bacteria, well, good luck to you, brave warrior – send our best wishes to the ER.

Shock the pool before you start your season – you know it makes sense.

2. You’ve Been Pooling It Pretty Heavily

Had yourself a pool party? Had a particularly pool-heavy week? Shock the pool.

As we mentioned, all the chemicals with which we coat ourselves will have gone into the water, providing a potential banquet for microbes.

Kill ’em. Kill ’em all. Shock your pool.

3. It’s Been Extra Hot And Sunny

Annoyingly, extra heat and UV rays from the sun can provide the perfect breeding ground for bacteria, and can lower the normal level of chlorine in your pool. Shock it to restore the chemical balance.

4. It’s Been Raining

What? We just said you should shock your pool after it was too hot.

We know. The thing is, rain can change the pH balance of your pool, and drop contaminants right in there, including bacteria ready to start breeding.

5. If You Smell Chlorine

Seriously? Yep, afraid so. If your pool gives off a strong chlorine smell, the most perverse thing in the world of pool maintenance is happening.

It means you’re low on chlorine. What you’re smelling are chloramines – which are given off when chlorine breaks down.

Also, if people are getting especially irritated eyes after swimming in the pool, it’s another good sign of chloramines. Shock the pool.

6. When You Close Up Your Pool For The Season

Yes, we know you’ll have to shock it again before you use it at the start of next season, but it can’t hurt to shock it before you close it up.

If nothing else, it will put you two weeks ahead of the bacteria!

So that’s when you should shock your pool.

Every two weeks during the season without fail, and in the event of any of those extraordinary circumstances, like sunshine, rain, and pool parties.

Shocking. Isn’t it?