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How Long After Shocking a Pool Can You Swim?

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Regardless of how experienced a pool owner is, shocking a pool can be unnerving because, when working with a large number of chemicals, even the tiniest error can spell tragedy. Many people wonder how long they should wait after shocking a pool before swimming because of these potentially harmful conditions.

It is essential to know how many chemicals it takes to shock a pool and why pool shocking is potentially hazardous. You should know these things even before the instructions on how long you need to wait after shocking before you can swim.

What is Pool Shock?

Swimming pool with a signage of under maintenance.

Pool shocking, also known as ultra chlorinating, is a cleaning process that involves administering three to five times the typical quantity of chlorine to keep your pool water clean and safe. In a short amount of time, the chlorine level rises dramatically. It’s not a good idea to shock your pool regularly.

In some situations, shocking your pool is required, like when you’ve neglected it or after a bad storm. If you have a saltwater generator, though, and check your chemical levels regularly, you might not need to shock your pool as often.

How Long After Shocking a Pool Before Swimming?

A group of kids diving into the swimming pool.

A lot of pool owners have only one question when shocking their pool. They want to know how long they have to wait before swimming again.

Sadly, there isn’t a consensus among pool professionals as to how long you should wait before swimming again. Despite the lack of widespread agreement, we were able to identify several indicators that helped us better understand when the pool is safe to swim in again after being shocked.

Because shocking a pool uses more chlorine than usual, it will take a little longer for the water to acclimatize. As a result, how long it takes to swim after adding chlorine to a pool is greater. There are various factors to consider before deciding how long you should wait. These factors include:

  • What is the state of your pool?
  • Are there any blooms of algae?
  • Is it on the verge of turning into a swamp?
  • How terrible is the odor?

Algal blooms in a swimming pool can require weeks of shock treatment. The more critical the problem, the longer the time between shocks and swimming.

Unfortunately, because everybody’s circumstance differs in how much chlorine is needed to shock a pool, there is no precise response for how much time to wait after shocking a pool. 

You should be able to swim as soon as the free chlorine levels are stable and you can see what’s at the base of the swimming pool.

Following the manufacturer’s directions on the back of the goods is another excellent rule to follow. Manufacturers typically include cautionary statements and instructions about disposal, storage, and how to use the item on the back of all chemicals.

Types of Shock

Man hands shocking a pool with chlorine.

Because various kinds of shock can affect how long you can swim after being shocked, the first thing to remember is to read the product’s recommendations on the packaging. This should indicate how long you should wait before swimming after shocking the pool with that specific sort of pool shock.

Chlorine shocks

A super shock treatment isolated in a white background.

There are two types of shocks that contain chlorine: calcium hypochlorite (Cal-Hypo) and dichloroisocyanuric acid (Di-Chlor).

Cal-Hypo is the most common one in the market. Not only is it the cheapest, but it’s also the most powerful. It decomposes in seconds, usually done in a vessel pre-filled with water before adding to the pool. Di-Chlor, on the other hand, is stabilized granular chlorine. It takes longer to dissolve than Cal-Hypo, and the stabilizer will cause your pool’s cyanuric acid level to rise.

Non-chlorine shocks

A non-chlorine shock treatment isolated in a white background.

These are also known as oxidizing shocks. They don’t use chlorine to eliminate impurities from the pool; instead, they use oxygen. Normally, you may swim after applying this type of shock in as little as 20 minutes. However, oxidizing shocks will not kill algae. You need chlorine shock for that action.

Testing the water after shocking

Man hands holding a pH test kit against the pool.

You can use test strips, liquid tests, or an electronic water tester to determine whether or not the water is safe. Before swimming can continue, free chlorine concentrations should be below 5ppm, preferably below 3ppm.

Before you test the water for the first time, let the chlorine shock stay for a minimum of 4 hours. After shocking, you should leave the pool pump running.

Here are some other rules to follow when adding chemicals to your pool.

Adding Calcium Chloride

Wait for a full filter cycle or at least two to four hours after adding calcium chloride to your swimming pool.

Adding Clarifier, pH, and Alkalinity

When you add acids, bases, and clarifiers to balance the chemical content of the pool, you should wait 20 minutes minimum before you use it.

Adding Muriatic Acid

You should wait for at least 30 minutes after adding muriatic acid to your pool to avoid skin irritation or burns.

Adding Floc

Don’t swim in the pool after applying flocculant to maintain its efficiency. Let it settle to the pool’s bottom before vacuuming it as garbage.

Adding Algaecide

After introducing algaecide to the pool water, you should wait at least 15 minutes before swimming.


Shocking a pool is an important part of pool upkeep. Although this procedure is critical for having your pool clean and healthy, it is also necessary to know how long to wait after shocking a pool to swim to ensure that the water is safe for you and other swimmers.