Is Filling a Pool With Well Water Okay? (Read This First!)

Considering using your well water supply to fill your swimming pool water? In this guide, we’ve shared everything pool owners need to know about using well water to fill a pool.

The short answer is yes, it’s usually okay to fill your swimming pool with well water. However, the quality and quantity of your well water may affect the suitability of using a well water supply to fill a pool.

🤔 Is It Safe to Fill a Pool with Well Water?

Yes, it’s generally safe to fill a swimming pool with well water.

Keep in mind, however, that well water often contains contaminants that will affect the quality of your pool water, like arsenic, iron, hydrogen sulfide, hardness minerals, and manganese. These contaminants could turn your water brown or green and stain your pool tiles, damage your pool’s filters, pipes, and pool pumps, and potentially lead to bacteria growth.

You’ll likely need to filter and treat your well water to make it suitable for use in a swimming pool.

📖 How to Know if Your Well Can Fill Your Swimming Pool

Before you fill your pool with well water, make these important considerations:

The Well’s Flow Rate

The flow of water from your well system determines whether the well will supply enough pool water. Pools require thousands of gallons of water, so if your well isn’t well-stocked, there’s a risk that you may not have enough water for the job.

Your well’s flow rate is a measure of how many gallons of water the well pump can draw from the aquifer per hour.

If your well produces more than 600 GPH (gallons per hour) of water, it has a high rate of flow. If your well delivers less than 150 GPH of water, its flow rate is slow.

There are obvious advantages of having a well with a fast flow rate in this scenario. You’ll be able to fill your pool quickly and with ease, while wells with slow flow rates run the risk of drying out during the filling process.

Whether or Not you Share a Water Table

Many well owners share their water table with their neighbors. In this case, the rate at which water flows from your well is likely to be slower.

Keep in mind that using pool water directly from your well may impact the volume and flow water that your neighbors receive – especially if you cause your well to dry out.

The Season

Chances are, you’re planning to fill your pool when the weather is warm. In the summer season, certain regions are prone to drought and dry weather.

During droughts, your well’s flow rate is likely to be low, and your well probably won’t supply the volume of water needed to fill your swimming pool.

If you use all your well water during a drought, you may not get any water until the end of summer, so consider whether or not it’s worth using your limited water supply to fill your pool.

Metals and Contaminants Present

Well water often seeps through layers of rock and soil before it makes it into the aquifer, picking up minerals and metals along the way. Some of the common well water contaminants are:

• Arsenic
• Calcium
• Cobalt
• Copper
• Chromium
• Hydrogen sulfide
• Iron
• Lithium
• Magnesium
• Nickel
• Selenium
• Zinc

When these metals and minerals get into your swimming pool, they may stain your pool tiles, clog up the pool filters and pipes, and (in the case of excess iron) increase the risk of bacteria growth. Certain minerals and metals also cause water to turn an unpleasant green or brown color and stain swimmers’ hair.

Your Water Usage

How many people in your home use your well water? How many bathrooms do you have? Do you constantly run water-using appliances, like washing machines and dishwashers?

If your water usage is higher than average, your well may be overused, increasing the risk of it running dry. In this case, it’s not advised to use several thousand gallons of well water to fill your pool.

Your Pool Equipment

The presence of ions, minerals, and metals in well water force your pool’s pumps, pipes, and filters to work overtime to achieve the desired results. This will cause your pool pump and filtration system to wear down at a faster rate than if you used a water delivery service or municipal tap water.

If you choose to use unfiltered well water to fill your pool, prepare to replace your pool equipment more regularly than normal. High iron and manganese levels will also damage your pool liner, shortening its lifespan. Make sure you’re prepared for the maintenance costs before you consider using well water in your pool.

⚖️ Pros and Cons of Filling a Pool with Well Water

Pros

It Saves Money

Using well water as your swimming pool water is virtually cost-free. As long as your well has a big enough capacity and flow rate, you can fill any sized swimming pool with well water without having to pay a high water bill.

Well Water Isn’t Metered

Unlike municipal water, well water isn’t metered. This means you can use as much or as little water as you need for your pool without worrying about how much money it’ll cost.

It’s Easy

You don’t have to hire a contractor or spend hours figuring out how to fill your pool with well water. Many pool owners are looking for a simple solution to fill their pool water, and using water from a private well is a good option.

Cons

You May Run your Well Dry

Depending on the size of your well and the current climate, filling a large pool with well water may cause your well to run dry. This is especially likely if you’re filling a large pool or your well delivery volume is fairly low.

It Takes a Long Time

You can only fill a pool slowly with well water. On average, it’ll take up to 9 hours to fill a 5,000-gallon swimming pool if your well has a flow rate of 540 gallons per hour. Some swimming pools are 10,000 or 20,000 gallons, requiring an even lengthier filling process.

You’ll Need Pre-Treatment

Well water commonly contains high levels of contaminants that are present in much smaller amounts in city water, such as iron, hardness minerals, and trace metals. You’ll likely need a filtration system to treat your water before you use it in your swimming pool.

You May Affect your Neighbors’ Water Supply

There’s a good chance that you share your water table with several of your neighbors. If you use hundreds of gallons of well water to fill your pool, you may end up limiting your neighbors’ water supplies.

📝 What to Do Before Filling Pool with Well Water

Before you fill your swimming pool with water from your well, follow these steps:

Step 1: Test Your Water

First thing’s first, test your well water to see what it contains. Well water tests can give you an invaluable insight into your water chemistry, including your water’s potential metal, mineral, microorganism, and chemical levels.

Testing your water will tell you whether you should filter the water to remove contaminants before filling your well.

Step 2 (Optional): Take a Sample of your Water to a Pool Supply Center

An optional second step that we recommend is to take a sample of your well water to one of your local pool stores. Ask for your water to be tested (you may need to pay for this). An expert in the store should be able to tell you whether your water is sufficient for use in a pool, or whether filtration is required.

Step 3: Install a Water Treatment System

If you don’t already have a suitable water treatment solution to eliminate calcium hardness, iron or adjust your water’s pH level, now’s the time to install one.

A water softener or a whole house water filtration system removes contaminants that are known to damage components of your pool and cause the sides to turn brown. Plus, because they’re installed at your water pipe’s point of entry into your home, these filters improve the quality of your entire water supply, including your tap water and your shower water.

🚰 How to Fill a Swimming Pool with Well Water

To ensure you aren’t impairing your own water supply (or your neighbor’s!), it’s best to fill your swimming pool gradually over the course of a few days.

To fill a swimming pool with water from your well, you will need:

• A garden hose
• An outdoor tap

Follow these steps:

1. Connect your garden hose to an outdoor tap close to your pool.
2. Alternatively, connect the hose to a faucet in your home.
3. Let the open end of the hose hang into your pool. If you have a raised pool, make sure the hose is heavy enough to hold the hose head in the pool.
4. Turn on your outdoor or indoor faucet to allow water to flow through the hose and into the pool.
5. Wait for the pool to fill. A small pool will take around 24 hours to fill, while a big pool takes around 48 hours to fill.
6. Switch off your indoor or outdoor faucet when the pool is filled.

🧪 How to Treat a Pool Containing Well Water

Once you’ve filled your pool with water from your well, consider the following treatment methods to keep your water in a good condition:

• Test your free chlorine and pH levels – Use an at-home test kit that shows free chlorine, pH, and alkalinity.
• Adjust your water’s free chlorine levels – Add pool chemicals or liquid chlorine to raise free chlorine levels or use a granular chlorine neutralizer to reduce levels.
• Adjust your water’s pH – Increase your pH with soda ash or decrease pH with muriatic acid.
• Adjust your water’s alkalinity – Add muriatic acid or baking soda to decrease alkalinity or add sodium bicarbonate to increase alkalinity.
• Reduce metals – Dissolve metals with a chelating or sequestering agent and vacuum the rust out of your pool.

🧠 Is Filling a Pool with Well Water Okay? FAQs

Can you connect your well directly to your pool?

Yes, you can connect your well directly to your pool and fill it with untreated well water. However, if you have dirty water, cloudy water, or hard water, it may damage your pool without pre-treatment. In this case, use a sand filter or a water softener to treat your well water before you add it to your pool.

Related: Is it ok to fill pools and hot tubs with softened water?

How long does it take to fill a pool with a well?

It takes about 24 hours to fill a small pool and about 48 hours to fill a big pool. As well as your pool size, the flow rate of water from your well determines the amount of time it will take to fill your pool. Make sure to regularly check up on the progress of the pool filling to avoid overflowing the pool.

What do you do after you fill your pool with well water?

Once you’ve filled your pool with water from your well, you should test your water’s pH, chlorine, and alkalinity levels, and adjust these levels if necessary. Add pool chemicals to your water following the manufacturer’s instructions.

Can well water make your pool green?

Yes, well water can make your pool green. This occurs if your well water contains metals, like copper, which are oxidized in water. This will give your pool a green color. It’s not dangerous, but you can remove metals with a suitable water filter to prevent staining on the sides of your pool.

How long can I run my well to fill a pool?

It’s advisable to run your well for no more than six to eight hours per day to fill a pool. This will prevent your well from being overused and drying out. The exact suitable running time for your well depends on the size of your well and its flow rate.

What’s the best filter for filling a pool with water from a well?

The best filter for a pool is a reverse osmosis filter when dealing with higher levels of heavy metals or a whole house well water filter. You need a filter that can remove iron, bacteria, hardness minerals, and other metals and chemicals that could damage the pool components and increase your cleaning duties.

Is it safe to fill a pool overnight?

No. Somebody should continuously check your pool as it’s filling, so you shouldn’t fill a pool overnight while you’re asleep. Time your pool filling for the daytime, when you’re awake and available to step in if something goes wrong.