How Much Does It Cost to Fill a Pool With Water?

Jenna Jonaitis
Written by Jenna Jonaitis
Updated May 10, 2022
A luxurious pool house behind a house’s swimming pool
Photo: Ursula Page / Adobe Stock

Most homeowners spend anywhere from $60 to $1,250 to fill an average swimming pool with water

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The cost to fill up an average-sized pool will range between $4 and $10 per 1,000 gallons of water. Your cost will depend on things like the size of your pool, where your water is coming from, and whether you’re filling it all the way or just topping it off. In total, most homeowners spend between $60 and $1,250 to fill an average-sized swimming pool with water.

Learn more about how much it will cost you to float on your favorite inflatable swan all summer long.

Cost to Fill a Pool per Gallons of Water

The amount of water it takes to fill a pool after installation varies greatly depending on the size of your swimming pool. 

Grab your calculator—You can determine how many gallons of water (aka water volume) your swimming pool capacity is by crunching a few numbers:

Circular Pool Cost Formula

Diameter Length (A) x Diameter Length (B) x Depth x 5.9 = Total Water Volume

Rectangular Pool Cost Formula

Length (A) x Length (B) x Depth x 7.5 = Total Water Volume

Note: If your pool has shallow and deep ends, you should calculate the average depth to determine how much water it holds.

A record of your pool's dimensions will make it easier to figure out how much water is necessary to fill it up.

Basic per-Gallon Formula

Once you know the total number of gallons your pool holds, look up your water rate on your bill to estimate how much it will cost to fill. 

Let's look at this simple formula:

(pool capacity in gallons/1,000) x cost per 1,000 gallons = cost to fill a pool with water

Let's say your water and sewer rate comes to $9 for every 1,000 gallons you use, and you have a 20,000-gallon pool. Here's how you can determine how much it will cost to fill your pool with municipal water:

(20,000 Gallons/1,000) x $9 = $180

Pool Size by GallonCost
10,000-gallon pool$90
15,000-gallon pool$135
20,000-gallon pool$180
25,000-gallon pool$225
30,000-gallon pool$270

Pool Water Source Types and Cost Differences

backyard with large empty pool
Photo: Александр Трихонюк / Adobe Stock

If you're using local municipal water, filling a swimming pool is pretty straightforward. But when you rely on a well or prefer a delivery service, the cost can get a bit more tricky to determine. Here's what to consider when choosing your pool's water source:

City Water

At an average of $0.004 per gallon, city water is the most inexpensive and most popular option. For 15,000 to 30,000 gallons, you'll pay between $60 and $120. Overuse fines of up to $100 in California, where drought is common, are common as well—be sure to check with your municipality before turning the hose on full-throttle.

Well Water

If you're using a well instead of city water, then you may not have any bills in the mail. However, your electricity bill will reflect the power the well pump uses to move water from below ground to your pool.

Use the above formula (pool capacity in gallons/1,000) x cost per 1,000 gallons) to find out how much your electric bill will increase. You'll determine how much electricity a pool uses per 1,000 gallons and the price of that unit from your utility provider.

To fill your pool with water, you'll need to know such information as the manufacturer, watt, age, and model of your well pump. A well pump is typically less expensive than a unit that uses city water. Keep in mind; you're not paying sewer fees on top of water costs.

On the other side, chemically unstable well water may need chemical treatments. To save money, you might need to mix half well water and half transported water. 

Water Delivery Service

Many pool owners consider hiring a local pool service to supply their pool with water. Consider the cost of the water supply, the type of water, and how many gallons you'll need.

Expect to pay between $1,250 and $1,900 for 30,000 gallons of water from a pool water delivery service.

Partial Fills

To refill a pool, you should estimate how much water it contains to avoid overfilling. For every 20,000 gallons of water, expect to add 1,000 to 3,000 gallons (or 15%) when refilling from a partial drain below the skimmer.

Throughout the season, you may need to pay for maintenance water as your pool loses water from leaks, evaporation, and kids splashing around.

Water Delivery Costs

Your water delivery costs will vary depending on your location. But, in general, water delivery costs range from $175 to $380 per delivery. If we assume that most trucks can deliver only up to 6,000 gallons of water per delivery, you’ll need to do some quick (and simple) math with the following formula:

Low estimate: Your pool’s size in gallons/6,000 x 175 = cost

High estimate: Your pool’s size in gallons/6,000 x 380 = cost

Frequently Asked Questions

The most straightforward approach to fill an in-ground swimming pool is to connect a garden hose from your exterior tap. Although, it's not the best idea if there's water scarcity or restricted rationing. If so, you'll want to make alternate arrangements like getting a water delivery service to fill your pool.

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