What are the Causes of Rust Stains in Swimming Pools

Rust stains are being caused by different things that might be present in your pool without you knowing it. When we see rust stain in pools, there is a sign that some metal is present in the pool water. And before we can treat the pool water properly we must check what are the causes of rust stains in swimming pools.

The stain can appear as a small spot on the wall or bottom of the pool area. We must remove the possible causes so we can know the right thing to do. And also for us to prevent these things from happening again.

Cause of rust stains in pools:

  • Oxidation of water

Water oxidation catalysis is the acceleration of the conversion of water into oxygen and protons. When water oxidation happens it also means that the water you use in filling your pool may have metals in it.

You can filter the water and add a “metal out”additive in this kind of scenario. It can also be a big help if you are sweeping and vacuuming your pool more often.

  • Metal items that are present in the pool

Dropping a metal item in the pool by accident or purposely can lead to rust stains. Any kind of metal like a nail or a bobby pin can cause a stain in the pool. making sure to remove such items as soon as you determine their presence in the swimming pool.

And if the stain is already visible you can use rust removing liquid or a brush that can help you in removing the rust stain in the pool.

  • Rebar and concrete rust

Below the plaster of your pool is crisscross of metal shafts called rebar. Rebar is a steel bar or mesh of steel wires used a tension device. This rebar will rust through if placed within an inch of the surface.

If not treated properly, rusting rebar can develop into a bigger issue. It could spread throughout the pool area and will cost much to repair. That is why it’s better to call a professional like My Pool Guy to handle this kind of situation.

  • Soluble and colloidal iron

Soluble iron or “clear water” is being drawn from a well and rusts when it comes into contact with the air. This kind of issue is easily solved by adding chemicals into the pool water to oxidize the iron. It can then filtered by a mechanical filter.

Colloidal iron, on the other hand, is a rust that is in the water and is usually bound together with other substances. In dealing with colloidal iron you can add chlorine to oxidize the iron from other substances.


Having the insight about the causes of rust stains in the swimming pool makes it easier for us to treat the cause. Making sure to get rid of the causes as quickly as possible.

And for all your pool needs call My Pool Guy for your pool guy!