How Many Hours It Takes To Fill Up A Swimming Pool

Swimming pools are the best way to cool down during those hot summer days. Furthermore, they are a great way to get some good exercise. Suppose you are refilling or filling up a newly constructed swimming pool. In that case, you may be wondering how long it’ll take before it fills so you can get in there and enjoy yourself. So, how many hours does it take to fill up a swimming pool?

It takes 24 to 48 hours to fill a standard swimming pool using a regular-sized garden hose fill source. However, as there are nine gallons that an average garden hose releases per minute, meaning 540 gallons will go into a pool every hour, this can change. A garden hose only fills one inch per hour.

How Many Hours It Takes To Fill Up A Swimming Pool

Filling up a swimming pool differs according to many things. Here is all you need to know, how math plays a role, and alternative ways a swimming pool can be filled up apart from a garden hose.

Read also: How do you raise the Ph in a pool.

The Hours It Take To Fill Up Different Sized Pools

Nine gallons are released every minute by a typical garden hose. That equates to almost 540 gallons every hour. For instance, it will take roughly 37 hours for a 20,000-gallon pool to fill up completely. 

So assuming the pressure of the water is 9 gallons per minute and the flow rate of the hose at 540 gallons per hour…

How Many Hours Does It Take To Fill Up A 10-Foot Pool?

It’ll take roughly 18.51 hours to fill up a 10-foot swimming pool.

How Many Hours Does It Take To Fill Up A 12-Foot Pool?

It’ll take roughly 22.22 hours to fill up a 12-foot swimming pool.

How Many Hours Does It Take To Fill Up A 15-Foot Pool?

It’ll take roughly 31.25 hours to fill up a 15-foot swimming pool.

How Many Hours Does It Take To Fill Up A 18-Foot Pool?

It’ll take roughly 33.33 hours to fill up an 18-foot swimming pool.

Different pool sizes and hours to fill it up. Roughly estimates

What Do You Need To Know Before Filling Up A Swimming Pool?

The important thing to figure out when filling up a swimming pool is precisely how many gallons that particular swimming pool is. This is usually stated on the pool plan. If not, it can be calculated using a simple online calculator.

It will be contingent on the size, depth, and volume of water that the pool can hold every minute. Volume is equal to length times width times depth times 7.5. in gallons. The pool’s surface area is calculated as length times width. The volume in cubic feet is obtained by multiplying that surface area number by the depth. 

Because there are 7.5 gallons in every cubic foot, multiplying the pool’s cubic feet by 7.5 will give you the pool’s volume in gallons. Pool diameter times average pool depth times 5.9 equals water volume capacity for a circular pool.

Square/rectangular pools
Circular pools

Basics Involved In How Long It Takes To Fill Up A Pool

Well, there is quite a bit of mathematics involved. This is because a swimming pool has to do with volume. It is helpful to ensure that everything is measured in the same units. Fear not, as online calculators are available.

This is because when you are faced with an empty pool, all you have is a one-dimensional velocity. This won’t cut it, as filling up a swimming pool is essentially about filling up a volume. Furthermore, one needs to determine the volume flow rate. This is basically the rate of the flow of the water source you are using to fill up the swimming pool.

Although there are more calculations involved, this is the end formula used to determine how long it would take to fill up a swimming pool:

Time to Fill = Volume/Volume Flow Rate

That said, when the focus is on general terms, the average swimming pool hopper will typically fill up fairly quickly. Normally within several hours before the swimming pool’s entire surface area is reached. Once the entire surface area of the swimming pool is filled, the general rule of thumb is that an individual’s standard garden hose will provide roughly one inch of the vertical height of fill per hour. 

For example, suppose 36-40 vertical inches need to be filled up using only one garden hose plugged into a water outlet. In that case, it will take 36 to 40 hours to fill up the entire surface area of the pool.

Would adding a second garden hose speed up the process and shorten the time?  

Yes, in that case, the flow rate might double depending on the size of the service line available in your home. For this reason, one can’t add hoses indefinitely as a water supply is typically limited to a single copper line that feeds the entire house.

So, if you think adding more hoses will make the pool fill up faster, you’re wrong. There is still only one line feeding all the possible hoses you could add.

This is why it is recommended that only two hoses be used to increase the flow. You can also borrow one from the neighbors to help fill up the swimming pool. Another inch per hour is gained for every hose added to the swimming pool. 

How Fast Would A Fire Truck Hose Fill A Private Pool

360 liters of water can be discharged every minute by a fire truck hose, known as a Crossley hose. A 50m x 25m Olympic-sized swimming pool typically has a volume of about 2.5 million liters. At a rate of almost 1/2cm per hour, it would require four days plus 20 hours to fully fill a swimming pool.


Private swimming pools, on the other hand, typically measure 3.7 x 7.3 meters and have a depth of 1.5 meters. At a rate of flow of 360 liters per minute, a pool of this size could be filled in about 1 hour and 52 minutes. Typically, fire agencies don’t make their trucks accessible for pool filling. They couldn’t react quickly enough in case of an emergency when filling a pool.

How Else Can A Pool Be Filled Up With Water?

Due to the quicker fill time and higher quality of the water, getting water delivered to your home via a truck is a viable alternative for filling pools. There is absolutely nothing you’ll need to do apart from contacting the company and setting up a date and time for the delivery. 

This is also the perfect time to look for any potential concerns like leaks and other difficulties while the pool is being filled up. These details can be missed when you fill your pool with a hose since nobody is looking. By the time problems are discovered, it will be too late.

Utilizing well water is one of your other options for filling your pool. The fact that well water is completely free makes it one of its benefits and, by far, the most affordable pool water supply. Unfortunately, this isn’t always enough to convince people as there are other factors to take into account.

The water quality is one of the biggest problems with using well water. The smell of well water is noticeable. It has a sulfurous odor. Additionally, elements you don’t want to swim in, like copper, iron, etc., may be present in well water.

Because of this, it’s crucial to verify the water potential before utilizing it. Even though is free, there’s a chance that it contains significant concentrations of contaminants that require expensive chemical treatment.


The time it takes to fill up a pool cannot be answered in a single manner. A 20-foot pool may be filled in pretty quickly if the water is brought in by a Fire truck. However, it could take a while if you want to fill up the pool with a garden hose. 

It depends on how many gallons of water per minute a hose can provide.

Now that you are aware that volume plays a crucial role in the time it takes and how long you can expect different-sized pools to take, you can figure out when you’ll be able to use your pool.

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