How to Correctly Size a Swimming Pool Overflow or Spillover.

I recently had a conversation with a very nice lady from the USA who had just installed a brand new hot tub at her house. However, she was facing an issue with the overflow, which wasn’t exactly what she expected, so she wanted to discuss how she could fix it.

Inspired by this conversation, I’ve created this video and article on the topic. As a bonus, I’ve also designed a very simple and easy-to-use calculator to guide you. So, let’s get right into how to correctly size a swimming pool overflow or spillover.

You can also find me on my socials;

When done right, an overflow looks absolutely stunning as you can see in another one of my builds here. As you can see in the picture above, the water travelling across the distance and entering in a beautiful arc is truly breathtaking. However, proper planning is needed to ensure everything functions as intended.

What Does a Faulty Swimming Pool Overflow Do?

What happens if the overflow isn’t sized correctly? The following issues could arise:

Gapping:
This creates a gap between the water and the pool edge, as seen in the picture below. This often results from insufficient pressure and doesn’t look particularly appealing.

Different Route:
Another possibility is that the water takes a different path than intended. For example, in this image, you can see the water flowing back on itself and dripping from the wall.

Drips:
Due to a lack of flow, the water might end up dripping rather than flowing, which can be an undesirable effect.

How to avoid these problems?

To avoid these issues, it’s crucial to get the opening size, the height of the waterfall, and the pump size with the correct flow rate all in sync. All three factors must align for a successful overflow setup.

You’ll need a pump that’s powerful enough for the opening size you plan to use. While it sounds simple, it can get complicated quickly. But don’t worry – I’ve created a calculator to help! 

This calculator allows you to input various values. Not only does it tell you if your variables are too ambitious, but it also provides the required flow rate and suggests a suitable pump size. Keep in mind, however, that this is a recommendation, so be sure to double-check your pump’s flow rate and size.

When using the calculator, you can enter your variables in either inches or centimetres. Just input your width, depth, height, and desired flow type, and the calculator will do the rest, giving you a complete overview of what you need.

Make sure to use the calculator when setting up a spillover for your swimming pool to ensure everything is correctly sized and the right setup is in place.

Can I Help You?

If I can help you in any way I would love to hear from you. You can get in touch using the form below.

Thanks - Andi

 

Hi, Andi here. I own Buildahottub.com and also write all of the articles and info pages on the site. Some years back now, I built my own hot tub but struggled to find the information I needed. So, once my tub was complete, I started this website to help others in their own pursuit of hot tub and plunge pools DIY building information.

Today, I've helped over 1000 DIY customers just like you all over the world build hot tubs and pools. Have a good look around the site, there are lots of resources here. Please do get in touch if I can help you. - Cheers, Andi