How to Install a Hydrostatic Relief Valve in your Pool or Hot Tub.

Install a hydrostatic release valve

To install a hydrostatic relief valve in your pool or hot tub may sound like a complicated process. With a complicated name can come a lot of confusion. Hopefully in this article, with my help you will be able to get your head around exactly what you need to do. You will quickly realise that it is not as complicated as it sounds.

Check out my YouTube Channel for more on this topic

What is a Hydrostatic Relief Valve?


A hydrostatic relief valve for a swimming pool to hot tub is a different type of device compared to the one used in marine and offshore industries.


In this context, the hydrostatic relief valve is a safety device designed to prevent damage to a swimming pool or hot tub caused by hydrostatic pressure build-up. Hydrostatic pressure can occur when the water table in the ground rises due to heavy rain or flooding, and the pressure can push up against the pool or hot tub’s floor, causing it to crack or lift out of the ground.


The hydrostatic relief valve is typically installed at the lowest point of the pool or hot tub’s floor and is designed to automatically open if the hydrostatic pressure exceeds a predetermined level. This allows water to enter the valve and equalize the pressure, preventing any damage to the pool or hot tub.



Why do I need to install a Hydrostatic Relief Valve?


You need a hydrostatic relief valve in your pool or hot tub as a safety feature to protect against potential damage caused by hydrostatic pressure build-up. Hydrostatic pressure occurs when the water table in the ground rises due to heavy rain or flooding, and the pressure can push up against the pool or hot tub’s floor, causing it to crack or lift out of the ground.


If the pressure builds up to a critical level, the pool or hot tub can become buoyant and lift out of the ground, which can cause serious damage to the structure and potentially injure anyone nearby. A hydrostatic relief valve is designed to prevent this from happening by automatically opening when the pressure exceeds a predetermined level, allowing water to enter and equalize the pressure. This helps prevent damage to the pool or hot tub and ensures the safety of anyone using or near the structure.


In addition to a hydrostatic relief valve, it’s important to ensure that your pool or hot tub is installed correctly and that the water level is maintained at the appropriate level to prevent hydrostatic pressure build-up. Regular maintenance and inspections can also help identify any potential issues before they become a problem.



What components make up a Hydrostatic Relief Valve?


Hydrostatic relief valves come in different shapes and forms – depending on which manufacturer you choose. I am going to explain the installation process here for the model that I supply both in Europe and the USA which is from Certikin.


The first part of the Hydrostatic relief valve is the bottom drain. This forms a key part for the valve as it is actually the housing that surrounds it. This also makes it possible to clean and replace the valve should you need to but remember to empty your pool or hot tub first.

Next is the actual valve itself. This is a normally closed valve, and the water pressure above will help keep the valve closed too. When the pool is empty and there is no pressure on the top of the valve, if the hydrostatic pressure builds up underneath, this valve can open to allow water into the tub or the pool and release the pressure – preventing damage to your tub or pool.

The final part of the hydrostatic relief valve is the water collector. This is a “spike” shaped attachment that is screwed into the base of the lower drain. This will be in direct contact with the dirt and gravel underneath the pool. This should not be concreted in place as that will defeat its purpose.

How do I install a Hydrostatic Relief valve?


The hydrostatic valve and its components need to be installed before you pour the concrete pad or base for your pool. Firstly, you need to assemble the valve. You should use PTFE tape on the joins on both the valve and the water collector. This is because they are screw in connections and we are not going to glue these in place – just in case we need to change them in the future.


To be honest, you could glue in the water collector as that will be underneath the base of the pool and you are not going to be able to get to it without removing the lower drain which you don’t want to do! The hydrostatic valve should not be glued in place in case you need to replace it in the future.


Please see the diagram below. This shows the positioning of the components in relation to the concrete base of your pool or hot tub that you are going to pour. If you are not using the drain as a drain, you can cap off the 2″ pipe connection.

hydrostatic valve installation
hydrostatic valve installation


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 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 700 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

Adding a Spill-Over Hot Tub to An Existing Swimming Pool

Are you dreaming of transforming your backyard into a serene and luxurious oasis? If so, [...]

Fibreglass Hot Tub Refurbishment – Case Study

Not every DIY Hot Tub project that I work on is a new design and [...]

Copper-silver ionization for Hot Tubs?

When it comes to maintaining crystal-clear and hygienic water in your hot tub or pool, [...]

Discovering the Bliss of Built-In Spas

Have you ever dreamt of having your personal oasis, a sanctuary where stress melts away, [...]

What are the Self-Priming Hot Tub Pump Options?

If you are not able to build your control room for your DIY hot tub [...]

Can I Use a Variable Speed Pump in a Hot Tub?

This is one of the questions that I do get asked regularly. There tends to [...]

Can I build a DIY Infinity Pool?

Are you dreaming of having your own luxurious infinity pool but feel intimidated by the [...]

How to Wire a Hot Tub Blower – The Correct Way!

If you own a hot tub, you know that it's important to keep it properly [...]