Say you’re just getting ready to cool off in your pool when you suddenly notice that something’s leaking from the area around your pool filter. You could start to worry about how much it would cost to fix the problem, and whether there was anything you could do to fix it. Most often, when there’s a leak in your pool filter, it’s usually caused by the O-ring.

There could of course be an issue with your O-ring, which is essentially a seal that’s designed to prevent any water from oozing out. But a pool filter leak could be caused by any number of other factors as well. But when the issue is your O-ring, the solution is relatively simple. However, what exactly is an O-ring?

What Is The Purpose Of An O-Ring?

An O-ring helps in creating a seal with the specific purpose of preventing any kind of liquid from oozing out. When it comes to the pool filter, a working O-ring is crucial. It’s what prevents water from leaking through the connections in the filter and entering the actual mechanism of the pool filter.

It’s usually made of either elastic or rubber. An O-ring looks like a rubber band, just larger. The name ‘O-ring’ initially came from the shape this ring has. Since then, various shapes and sizes of O-rings have been made available. They can all be used to prevent water from leaking out, in the same way. They’re all called O-rings, even if they come in different shapes.

O-rings these days aren’t just used in pool filters either, they can be used in everything from the pool pump to the pool valves, the skimmers, the chlorinators, and more. O-rings are also vital for the equipment they are placed in. If there’s a problem with the O-ring, then this could cause the whole system to be affected as a result. It’s most common, however, for O-rings to be found in pool filters.

Signs Something Is Wrong With The O-ring

If you want to check whether there’s anything wrong with your O-ring, then there are two things that you’ll need to do. The first of these is to visually inspect the O-ring, to see whether it needs replacing or not. In order to properly diagnose what could be wrong with your pool filter O-ring, for example, you’ll need to look for one of three things:

  • Whether the pool filter is leaking or not. The pool filter could also leak when pressure is applied, or even if it’s turned off.
  • Whether the filter pressure has decreased or not. You’ll need to check the pressure gauge of your filter. Should there be gaps within the seal of the filter, then the system could end up losing pressure.
  • Whether the water level in the pool has reduced or not. This especially applies to pools that are above ground.

You should also check to see whether there are any cuts, or any signs of breakage, in the actual O-ring itself. If you haven’t been lubricating your O-ring, then this could cause damage. When it isn’t lubricated properly, it can crack and even dry out. As a result, the pool filter may leak.

Also, watch out for a smell. If you get the smell of a tire burning when you go near your pool filter, then this can indicate that something is wrong with the O-ring. This is because an O-ring is made of elastic or rubber, and located close to a motor in the system. When the O-ring becomes worn, it can smell like a tire that’s burning. All this applies to other pool equipment where you may have used O-rings as a seal, as well.

How Often Does The O-Ring Need To Be Replaced?

How often you need to replace the O-ring will depend on what pool filter you have. You can always consult your newcastle pool installer for advice on which O-ring to purchase. It can also depend on the kind of O-ring you have. There are fibreglass pool owners who choose to get their O-rings replaced every year, but this isn’t always necessary.

Consider investing in a quality O-ring, as a good ring will last you many years. Some even last up to fifteen years without needing to be changed even once. There are also O-rings that are only meant to last as long as the filter does. So check the specifications of your O-ring carefully, before you purchase it.

Even if you don’t replace your O-ring every year, you should inspect it annually nonetheless. You’ll also need to lubricate it from time to time.

What You Should Know About O-Rings

O-rings are commonly used as seals when it comes to pool equipment. This is because manufacturing them is cheap, and they are also durable. An O-ring can be used to seal pressure exceeding hundreds if not thousands of pounds.

The kind of O-rings used in pool pumps and pool filters are made using EPDM rubber. For the chlorinator, O-rings are made using fluorocarbon, FKM, or Viton. O-rings will also need to be lubricated, ideally with a silicone lubricant. If this isn’t done on a regular basis, then the O-rings can become dry. Once this happens, it will start to crack. Then it won’t be able to work as a seal anymore.

Remember to not use Vaseline or petroleum jelly to lubricate the O-ring. This can destroy O-rings that are made of EPDM if done over time. An O-ring is an elastomer loop that has a round shape. It comes with a mechanical seal that can be placed within grooves and then compressed. O-rings tend to be available at certain diameters, and they also have particular thicknesses. The measurement of thickness of an O-ring is usually in inches. Common sizes include 1/6″, 1/8″, 3/16″, and more. You could also have a large filter that needs an O-ring which is 1/2″, and these are also available.


O-rings create a seal where they’re placed, preventing liquid from seeping out. Usually, you’ll find them used in pool pumps and pool filters, but they can be used in other equipment as well. Say something does go wrong with the pool filter, and this can happen if you haven’t been lubricating them. Then the first sign you’ll notice is a leak. You could also get the smell of a tire burning.

Use this guide to learn what an O-ring is, how to maintain it, and what to do when there’s a problem with your O-rings.