Should I Know the Volume of My Pool?

Is it really so important to know the volume of our pool? Or can it merely be felt the way one feels when adding mayo to a potato salad. “Just a glop of this chemical and a dash of that chemical… that feels about right. Hope the pool stays clean and clear!”

I would gently encourage the reader that the more you know about your pool, the more equipped you are when it comes to your pool care. This may seem more obvious if you plan on being a DIY owner who is hands on with everything from cleaning, repairing, and winterizing. However, even for the pool owner who hires a company to handle the week to week demands of a pool, the more you know about your pool, the better off you are in general.

Knowing at least a rough estimate of the volume (also referred to as gallonage) of your pool ensures you can better identify what equipment works best for circulating your pool water. It also minimizes the chance of over-dosing your pool with unnecessary chemicals. All pool chemicals are safe within their proper moderation. We want to limit unnecessary risk to your family and loved ones. Proper chemical application starts with knowing how many gallons of water need to be balanced.

I am going to share with you some easy calculations that will help you know your pool better. For surface area, Length and Width are necessary. For total volume or gallonage, Length, Width, Depth, and cubic factor 7.48 are necessary. When solving for volume, remember that 1 cubic foot of water equals 7.48 gallons of water, hence we multiply the total cubic feet (LxWxD) by 7.48. For a pool with a sloped base, simply find the average between your two Depths (Depth1+Depth2)/2.

Note the above models simply calculate the surface area of the pool (ideal for calculating skimmer flow) and the volume of an even bottomed pool. But what of a pool with a gradual depth or slope? See below:

Many homeowners have round pools. For round pools, you need to know the diameter, or length across the pool. For ovals, you need to know both the long and short diameter. Using the diameter(s) to determine the radius(s), you will be able to calculate at least a rough estimate of gallonage. Don’t forget pi=3.14.

Oblong is distinct from an oval because its sides are straight, not rounded. This general shape is found in roman styles pools, giving the pool an elegant, classic look. This also changes the calculation formula slightly for finding both area and volume. Imagine you are essentially calculating a rectangular pool and a circular pool together. We will take the Length times Width like a rectangle, then pi times radius times radius like a circle, and add them. Then multiple by the depth and cubic factor 7.48. And if there is a slope, we will multiply our rectangle + our circle by first the average depth and then the cubic factor 7.48.                                                   

Consider if you will a kidney pool. Perhaps a little less straight forward than the rest, there is an additional kidney factor 0.45 that we use to calculate the area and volume of a kidney shaped pool.

The better you know your pool, the better your pool owning experience will be. From proper chemical treatment to knowing what equipment will be most effective at circulating your total gallonage to keep things tip top and clean, calculating your pool’s area and volume is a skill all pool owners should have in their ready repertoire.