Hot Tub Cover Odor: Why & Fixes

There are a few reasons why your cover might develop a strange smell. In most cases, though, the odor comes from the condition of the spa water. Keeping the water properly balanced and maintaining the right sanitizer level usually stops covers from smelling bad.

Outer Cover Layer

Figuring out the source of the smell means doing a simple process of elimination. Start by taking the cover off the tub and moving it to a spot where you can spread it out. Unzip the outer layer and carefully remove the foam inside.

Check the outer layer thoroughly for tears or holes. Small to medium-sized holes or rips can be fixed with a vinyl patch kit. For the best results, clean and dry the outer layer (both inside and out) carefully before making repairs. If the outer layer has large holes or the material is breaking down, it’s beyond fixing and should be replaced.

You can learn more about caring for mold on or in spa covers elsewhere.

Inner Protective Liner

The foam inside a hot tub cover is sealed with a protective plastic liner (called a vapor barrier) to keep moisture out. Check this liner for holes or splits along the seams.

If the vapor barrier around the foam core is punctured or torn, but the foam itself isn’t soaked with water, try drying the foam and fixing the liner with a patch kit. If the hole or tear is too big to patch, or if the foam core is saturated, it’s time to get a new cover.

Tip: A good sign that the foam core has rotted or become waterlogged is that the cover will feel very heavy.

Broken or Cracked Foam

If the foam core is broken or cracked, the cover will lose its shape over time—and eventually, it will start touching the spa water. Any contact with the water will make the cover break down even more. In this case, replacing the cover as soon as possible is the best choice.

Water trapped inside the foam gets stagnant quickly and starts to smell. Once the foam in the cover is waterlogged, it can no longer keep heat in—which will make your electricity bill go up sharply.

Hot Tub Cover Cleaners

It’s common sense to use non-abrasive, oil-free cleaners made specifically for hot tubs and their covers. While other cleaners exist, they can actually damage the cover over time. Cleaners not meant for hot tub covers can also get into the water and throw off its chemical balance.

Not sure where to start? Look for a care kit made for spa covers—it will have everything you need to keep your cover in good shape!

*Never use bleach, drain cleaners, or other household cleaners on your hot tub cover. These products can speed up the cover’s breakdown.

Prevention

Taking care of both your hot tub cover and the spa water is key to keeping the cover like new.

Set up a monthly cleaning routine for your hot tub that includes maintaining the cover.

Tips:

• Try to keep the top of the cover free of debris, dirt, and dust. This will prevent damage to the cover and stop debris from getting into the water.
• Using a protective spray can keep the cover from fading and cracking.
• Don’t use treatments that have silicone oil—they will speed up sun damage and wear.
• Every few months, take the cover off and put it in a dry, safe place to let it air out.
• Use a floating blanket for the spa to protect the cover from too much chemical evaporation and moisture.
• Make sure the spa water is always properly balanced. Water that’s out of balance can let bacteria grow or cause the cover to break down. Poorly maintained water can lead to bacteria growing on or inside the spa cover.