How Long Does It Take to Fill a Backyard Pool with a Garden Hose?

Swimming pool garden hose

If you want to fill up your pool, you must know all the elements involved. For example, you must understand the time it will take to fill the container, how much water you need, and how much it will cost you. Once you understand this, you will have an easy time making your pool safe and beautiful to swim in.

You may use several methods to fill your pool. For example, you could do it manually with buckets, call for pool refilling services, or use a garden hose. The garden horse method is the most common amongst pool owners, but how long does it take?

Filling your swimming pool with water will take a few hours or more than a day depending on its size. It may also vary depending on your water pressure and the size of your garden hose. Overall, it is the easiest method since you only need to connect the hose to a water tap and dip it in the pool. Leave it in there overnight or for the estimated appropriate time.

The following article will help you understand the timespan and cost of filling various pool sizes. It also discusses a few significant items you need to know about if you want to maintain a safe and beautiful swimming pool.

Read more about Above Ground Pools!


How Long Does It Take to Fill a 10,000-Gallon Pool?

Let’s assume that your water pressure pumps roughly 10 gallons per minute, translating to 600 gallons per hour, through the outside water hose. With this speed and capacity, it will take around 16.67 hours to fill a 10,000-gallon pool.

With that in mind, how long does it take to fill a 15,000-gallon pool?

If you take the above example, with a water pressure pumping about 600 gallons per hour, it will take about 25 hours to fill a 15,000-gallon water pool.

How Long Does It Take to Fill a 20,000-Gallon Pool?

Now, based on the same assumption, with the same water pressure pump, it will take you about 33.33 hours to fill a 20,000-gallon pool with water.

It is quite easy to determine the number of gallons per hour you water pressure pumps via your hose. You can apply a couple of methods to do so, using everyday items you already have in your backyard or garage.

Here is what you need:

  • Gallon jug
  • Five-gallon bucket
  • Water hose
  • Calculator
  • A stopwatch (can be a smartphone timer Alexa App)
  • Someone to hold the stopwatch

Procedure One: Using a One-Gallon Jug

Have someone hold the stopwatch, then hold the hose ready to fill one gallon with water. Have the timekeeper start the time as you begin to add water into the jug.

Signal the helper to stop the time as soon as the jug is full, then use your finding to calculate your gallon per hour rate.

The formula will be:

(a÷60) × 60

You will obtain the number of seconds it took to fill up one gallon.

For instance, if it took you 20 seconds to fill the gallon, your Gallon Per Minute results will be (20÷60) × 60 = 20. Then, multiply the result (20) by 60 to convert it to Gallons Per Hour (GHP). It will be 120.

Procedure Two: Using a Five-Gallon Bucket

You will still need your friend or family member to operate the stopwatch as you run the procedure. Place your hose in a bucket and tell your timekeeper to start the stopwatch once you turn on the water faucet. Then, tell them to stop the watch once the bucket is full.

Use the same method as the one described above to determine the Gallon Per Minute speed of the horse. For example, if it took you 40 seconds to fill the 5-gallon bucket, the GPM conversion goes as follows:

(Bucket Size in Gallons÷ Seconds) × 60, which in this case translates to (5÷40) × 60 = 7.5 Gallons Per Minute. Then, multiply this result by 60 to get the GPH, which will be 7.5 × 60 = 450 GHP.

It is important to note that the five-gallon bucket formula applies to any size of the bucket. Whether it is a 10-gallon bucket or a 20-gallon one, you have to get the numbers right and carry it forward to the calculations.

The first method, gallon jug, is very easy, but using bigger bucket yields more accurate results.



The cost of filling your pool will depend on the amount you pay on your water bills and the size of your pool. One thousand gallons of water roughly cost about $4 to $10, but this will also depend on your state’s charges. This is what I will use in this case.

How Much Does It Cost to Fill a 10,000-Gallon Pool?

A 10,000-gallon pool needs ten times what we estimated above, so you will multiply the cost for 1,000 gallons by ten. If we take the lowest rate, $4, the cost will be as follows:

$4 × 10 = $40

How Much Does It Cost to Fill a 15,000-Gallon Pool?

Following the same example: a 15,000-gallon pool requires 15 times the amount mentioned above. Therefore, it will cost you $4 × 15 = $60 to fill your swimming pool.

How Much Does It Cost to Fill a 20,000-Gallon Pool?

On the other hand, a 20,000-gallon swimming pool will require 20 times the amount. So, it will cost $4 × 20 = $80 to fill your 20,000-gallon swimming pool.

You must determine the number of gallons it takes to fill your pool before determining the cost. There are several methods to do so, but the easiest one is to use the material you got from your pool manufacturer or seller after the purchase.

If you can’t access this information, use simple math to calculate your pool capacity. The following formula will come in handy depending on the shape of your pool.

For a rectangular pool, you will use this typical formula for calculating an area of a cuboid:

Length (L) × width (W) × height (H) × 7.5 or Length (A) × length (B) × depth × 7.5

For a circular pool, use pi (3.14) × radius × the average depth in feet, then multiply by 7.5.

For pools with uneven surfaces (shallow and deep ends), you have to use an average water depth. Do this by simply averaging a close middle ground digit between the lowest and highest points.

Here is our article why you must fence in your pool.


Will Two Hoses Fill a Pool Faster Than One?

Two hoses working together at the same time will bring in a stronger water flow unless your water pressure is extremely low. This is doable when you have a line with enough pressure.

On the other hand, splitting your supply into two is not a sure way to double the flow rate because there will be a pressure drop. It will boost the flow rate by a significant margin, but without doubling it. You can test this with an empty bucket, timing the duration it takes to fill one with a single hose vs. the time it takes with two.


How Often Should You Have to Add Water to a Pool?

You might be surprised by how much water your pool loses due to evaporation. Normally, swimming pools lose between 2 and 3 gallons of water every day. This roughly translates to between 2 and 4 inches per week. In total, a typical-sized pool loses between 25,000 and 50,000 gallons of water per year.

The evaporation rate in your pool will vary depending on the wind, pool heating, and temperatures. Therefore, you should drain your pool water every five to seven years. However, ensure that you drain and refill your pool water in mild weather to avoid damage resulting from direct heat and sunlight.

You can reduce the number of times you need to replace your pool water with proper pool maintenance. Doing this protects your pool from various harmful water elements, like algae growth.

Even with this, you must keep in mind that leaving your pool empty exposes the facility to conditions like hydrostatic pressure. Hydrostatic pressure is the groundwater pressure around and under the pool that pushes the walls and floor. In concrete pools, it causes the floors to shift and crack, while in vinyl and fiberglass swimming pools, hydrostatic pressure can lift the floor, damage the walls, or do both.

Ensure that you know the exact amount of water you need to add. You will need your pool’s capacity when treating it. You can check the manufacturer instructions or ask your local pool assistant.

As previously stated, there are various ways to add water to a pool. You can either do it manually with buckets or use a garden hose. Alternatively, you can use pool water delivery services if you are not sure of the process, although these can be a bit expensive.


What Should You Do If the Pool Water Level Is Too Low?

The skimmer can bottom out and invite air into your filter if the water level in the swimming pool is too low. When this happens, it may burn the motor on the pool pump. This could result in expensive damages, meaning that you must keep a keen eye on your swimming pool water levels at all times.

If you want to maintain a perfect water level, consider investing in an automatic water leveling device. These devices are very reliable and come with different features and at prices. In addition, they are simple to use as you only need to attach them to your garden hose or any other water source and let them do the rest.

The devices detect when your water level gets low and automatically fill the pool to the required level. This reduces the need for manual work, protecting your pool from concerns related to a low water level.


What Should You Do If the Pool Water Level Is Too High?

First, your skimmers won’t work if your swimming pool water level is too high. While this isn’t critical to the facility’s functioning (especially compared to critically low water levels), it can lead to more maintenance work for you.

If your skimmer basket unable to catch the slack, you will have to get there and pick them yourself.

In most instances, you won’t need to do much when it is fairly on the high side. Natural activities, like wind and evaporation, will quickly lower the water level to the desired point. However, you mustn’t intentionally make it extremely high knowing that this will happen. Just do what is right and fill it every time it becomes too low.


What to Do After Adding Water to a Pool?

Pool preparation does not stop at adding water. Instead, it involves a few safety practices to eliminate any hazards that may occur to the swimmers.

While filling your pool, you are likely to introduce debris into the new water. When that happens, you need to vacuum and skim any foreign materials that could damage your pool liner. Also, ensure that you use a pool skimmer to remove any debris floating in or on top of the water.

After adding water to your pool, you must test it. You can do this by yourself with a DIY test kit or strips, or you can hire a local water testing company to provide a professional touch.

Testing your water ensures that there is the right chemical balance inside the pool. We recommend you do this before you allow anyone to swim in the pool.


Bottom Line

Your pool water level fluctuates daily due to the running pump and rainwater. As a result, you have to ensure that you maintain the ideal level. Check the level daily to make sure that everything is normal.

It is also important to perform routine maintenance activities, like backwashing, skimming, and vacuuming the pool. This will lower the water levels and ensure you add water as needed.

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