Should You Fill Your Pool With Well Water?

Written by Michael Dean
August 25, 2023

filling a swimming pool with well water

If you’re a pool owner with a well in your yard, you might wonder: Can well water be used to fill your swimming pool? And you know what, fair question! After all, wells are historically a source of clean groundwater that comes from deep beneath the bedrock, and it is a potentially viable option for filling up a pool if needed. However, while the answer is technically yes, there are a few important points to consider before you proceed.

In this article, I’ll explore whether you should fill your pool with well water, the pros and cons of doing so, and how to fill the pool with well water. Let’s dig in!

Main Takeaways

  • Filling your pool with well water is possible, but you must consider issues related to water quality, mineral content, and flow rate of the water.
  • One main factor to consider when determining if your well can fill your swimming pool is the flow rate of your well.
  • Even if your pool has a high flow rate, you need to fill at a gradual pace to avoid overwhelming your household’s water pressure and the pool’s plumbing and filtration system.

Should You Fill Your Pool With Well Water?

While you can certainly fill your pool with well water (in fact, it’s one of the more affordable options available to pool owners), the question is: Should you? Well, before you go ahead and fill up your pool, there are a few points to consider.


Well water is generally “hard,” meaning it contains many hard minerals, arsenic, iron, hydrogen sulfide, nickel, selenium, lithium, cobalt, manganese, and other trace elements that could affect your water. These contaminants could potentially stain your surface or build up in your pipes.

If your well water is particularly “hard,” I don’t recommend using it to fill your pool unless you can filter, soften, and chemically treat your well water. That said, if you can treat and filter the well water you can, you can definitely fill your pool with it!

Before proceeding, ensure the well water is tested for quality and safety. This can help you identify any potential issues that need to be addressed. For this, I suggest you speak with water treatment specialists.

Flow Rate

Along with the higher mineral content of well water, you will also need to consider the size of your pool and whether the well will have enough to fill the pool. The last thing you want to do is run your well dry when filling your pool. The answer to this depends heavily on the time of the year, as the flow rate is likely to be low during dry seasons. But you essentially need to determine how fast water is flowing into your well and whether or not there is enough volume to fill your pool. 

More on this below!

How to Know If Your Well Can Fill Your Swimming Pool

As mentioned above, the main factor to consider when determining if your well can fill your swimming pool is the flow rate of your well. This is the amount of water that your well can pump per hour. Pools need thousands of gallons of water (the average pool is between 10,000 and 20,000), so there’s always a risk that you may not have enough water for the job. Generally, it’s better to have a higher flow rate, especially with a large pool. 

You only need one simple calculation to know whether your well can fill your swimming pool. Divide the volume of your pool with the well flow rate to get a picture of how long it will take to fill your pool. For example, if your well produces 600 gallons per hour (which is a high flow rate), it’ll take around 33 hours to fill up a 20,000-gallon pool.

20,000 (volume) / 600 (well flow rate) = 33.333 (hours)

Check out my pool volume calculator for some help determining the volume of your pool.

You can expect it to take a few days to fill your pool with well water. If it takes any longer than that, it may be worth looking at another option.

Pros and Cons of Filling a Pool With Well Water

As you can probably see, filling your pool with well water definitely has its pros and cons. 


  • Cheaper: Well water is free, so using well water to fill your pool can save you money on water bills.
  • No chemicals: Well water is usually free of chlorine and other chemicals present in tap water. This can be beneficial if you prefer a more natural swimming experience or if you have sensitivities to chlorine.


  • Contaminants: Well water might contain minerals, sediments, and other impurities that can affect the clarity and cleanliness of your pool water, such as higher mineral content than tap water, which can lead to scaling on pool surfaces, staining of equipment, and damage to plumbing.
  • More work to balance chemistry: Treating and clearing well water might require a bit more effort to balance the pool’s pH, alkalinity, and other chemical levels due to its unique mineral composition.
  • Strain on water supply: Filling a large swimming pool with well water can strain your groundwater supply. If your well’s capacity isn’t sufficient, it might lead to reduced water availability for household needs or even affect neighboring water supplies, leading to unpleasant disputes.

How to Fill Pool With Well Water: Step-by-Step

So, you’ve decided to go ahead and fill your pool with well water. Filling a pool with well water requires careful planning and attention. Here’s my step-by-step guide to help you through the process:

Step One: Test and Treat the Well Water

Before anything, test the water in the well to determine its quality, mineral content, metal content, and other contaminants. Based on the results, you might need to opt for necessary water treatment options such as filtration, softening, or chemical treatment to address impurities.

Step Two: Check the Well Flow Rate

Keeping in mind the amount of water needed for your pool, test your well flow rate. Ensure your well has the capacity to supply the required volume of water without causing issues with your household water supply.

Step Three: Connect the Hose

Attach the garden hose to the well pump’s tap and connect the hose filter. Then, take the open end of the hose and put it inside the pool.

Step Four: Switch on the Pump

Turn off the pool equipment and switch on the well pump. The pump will now begin to pump water from the well into your pool.

Step Five: Fill the Pool

Slow and steady does it! Even if your well has a high flow rate, fill the pool at a gradual pace to avoid overwhelming your household’s water pressure and the pool’s plumbing and filtration system. I recommend taking a break after a couple of hours. Carefully monitor the water pressure and flow to be sure your well doesn’t run dry, as this can spell disaster for your well pump.

Generally, it can take anywhere from a day to three to fill a pool, depending on the size of the pool and the well flow rate.

Switch off the well pump and detach the hose to stop filling the pool.

Step Six: Balance the Pool Water

After filling your pool, test the pool water. Use a pool water testing kit to test the water. If your pool water testing kit doesn’t include tests for minerals and metals, make sure to get a drinking water test kit as well. Adjust the water chemistry as needed to maintain proper balance. You might also need to backwash the filter to remove any sediment or particles introduced during the filling process.

Allow the pump to run for a few hours before retesting the water again to ensure everything is balanced before jumping in the water.

Alternative Water Sources for Filling up a Pool

What other options do you have if you’ve determined that you cannot fill your pool with your well water?

Tap Water

Tap water is easily the most common water source for filling pools. It is safe to use, but keep in mind that it is being sourced from your local municipal water supply, which means it could contain traces of chlorine or other chemicals that can affect the pH balance of the pool water. You’d have to add additional chemicals to the pool water to treat it for swimming pool use.

Pool Water Delivery

Another option is pool water delivery. These services offer water specifically treated for pool use. It’s definitely the most expensive option, but it can save you a ton of time and hassle. All you need to do is order the water, pay for it, test and balance the water, and enjoy your pool!


Rainwater is a free and natural water source that can be used to fill pools, but just like well water, it can contain chemical pollutants, dust, debris, and particles, so it is just as important to test and treat it properly before pouring it into your pool.


A final option is graywater. Graywater is wastewater from household appliances such as washing machines and dishwashers. It’s a good way to reuse water in an environmentally conscious way and can be used to fill pools. But as always, make sure to test and balance the water before jumping into the pool.

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It’s All About Balance

Remember, the key to successfully filling your pool with well water is proper preparation, water quality management, and ongoing maintenance. Regular testing, monitoring, and adjustment of chemical levels are always necessary to ensure the pool water remains safe, clear, and enjoyable for you and your family.

If you’re uncertain about any step in the process or if your well water has specific challenges, please feel free to reach out to me! I’ll be happy to help clear up any questions you may have.

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