Hot Tub Smells 101


Hot tub smells like chemicals

Sometimes you find it hard to enjoy your hot tub because you cannot stand the smell of chemicals in the water. This might be because of two main reasons:

  • Your sanitizer is working harder 

The chlorine or bromine is working too hard to oxidize contaminants. This is a clear sign that you either need to drain and thoroughly clean your tub or at least shock it. The former will serve you better.

  • High chlorine or bromine levels 

Alternatively, if your chlorine or bromine levels are relatively high, you will feel the chemical smells, especially when trying to take a deep relaxing breath. You will need to use test strips to prove that this is the reason before resolving it.

How tub smells musty

A musty smell develops from high alkaline conditions that encourage mold growth. In most cases, your tub smells musty because of these two reasons:

  1. You cleaned your tub with some soap that later accumulated around your tub’s sides. It could be that mold is also building around the cover edges or side walls because of exposed air plus the soap’s effect.
  1. Another common cause of such musty smells is an idle hot tub. If you have not been using your tub for a while, chances are you will start smelling the dump on the tub’s cover. When water stagnates, even around the pipes, it can easily cause such uncomfortable smells.

How tub smells like fish

A fish-like smell in your tub could be as a result of various factors.

  • First, if you have had metal accumulation for a while without realizing it, some naturally occurring material from such water can cause the fishy smell.
  • Secondly, your tub could be having a chloramine problem. This happens when chlorine and ammonia combine.

When someone willfully or accidentally relieves their bowels in the tub, they introduce ammonia, giving the two chemicals the opportunity to interact.

How tub smells like plastic

A plastic smell in your hot tub could last long after you have drained and cleaned it. Although thoroughly cleaning your tub is supposed to leave it fresh for use, if you do not check vital areas such as the plumbing infrastructure, you will not have entirely solved the problem.

When the plumber is fixing plumbing issues, especially leaks, there might be a chance that water films found their way into the plumbing system. Since you will not have a clue about this, the water will sit there for some time until it starts dispensing the plastic smell. People using bromine as sanitizers often have the biofilm problem too.

How tub smells like rotten eggs

The purging rotten eggs smell is quite common with hot tubs, especially those that are not adequately maintained. Other times it could be due to too much Sulphur build up in the home water supply. This often comes naturally when the tub is left open during a heavy downpour. If there is excessive corrosion of metals in the tub’s water, excess electrons can bring the sulfides.

Once these sulfides combine with the hydrogen atoms in water, it causes hydrogen sulfide, hence the nasty rotten egg smell. Unfortunately, this happens naturally, so we cannot entirely stop it from tainting the water supply. It is even worse for people taking water directly from a well as no chemicals are added to help balance the sulfide molecules. Water supplying companies use chlorine to remove such unwanted sulfides.

How tub smells like burning plastic

It’s one thing for your hot tub to smell like plastic and a whole other issue with a burning plastic smell. The latter has a lot to do with your heater or too high temperatures that start burning your pipes.

If you are experiencing the burning plastic smell, check around your heater’s area to make sure that there are no sparks or melted surfaces. It could also be a sign that your heater is faulty, and you need to get it checked as soon as possible before it causes more harm. Ensure that there are no loose electric wires as well.

If none of these seems to be the problem, you might have overheated the tub, such that it started melting some pipes or rubbers attached to the tub.

How tub smells like mildew

Hot tubs collect mildew in the same way that it does algae. The two are not entirely similar, but environmental conditions can encourage their growth. If you can smell mildew from your tub, then chances are the contaminants have been there for a while. Check around the tub’s walls to see if you can picture some black or greenish spots. If not so, then the issue could be around your pipes or filters.

Your hot tub’s cover could be another significant carrier of mildew, which contributes to the smell around the tub even after lifting off the cover.

How do you get the smell out of a hot tub?

How you deal with uncomfortable smells from your tub will depend on what type of smell you are experiencing. However, in most cases, the issue is related to maintenance or general tub’s hygiene.

You can temporarily shock the tub with chlorine and balance out your chemicals to do away with certain smells. For more fulfilling solutions, drain your tub’s water and keenly clean every corner.

Use recommended detergents and make sure you wipe the soap completely. Leave the tub to dry while checking the pipes, jets, and valves. This ensures that no other contaminants or stagnant water is hidden there. Once the tub is sparkling and dry, you can then refill it and add the chemicals needed to balance out the water.

What makes a hot tub smell bad?

Unless there is a dumpsite nearby, when your hot tub is smelling bad, there might be a problem with the tub’s water, plumbing system, or surfaces. The hot tub might start smelling if:

  1. The pH levels are high, causing a musty smell.
  2. You haven’t used the tub for some time; thus, the water has settled long enough to allow algae or mildew growth.
  3. Bacteria are quickly accumulating around the plumbing system since they haven’t been cleaned or checked for a while.
  4. Filters have nasty contaminants or debris that decay or gather water films with time.
  5. The cover isn’t clean, so its dirt dissipates into the water every time you use it.
  6. Your chlorine or bromine levels are out of balance, causing heavy chemical smells.
  7. The tub’s water has Sulphur that combines with water molecules to create hydrogen sulfide.

How do you get the bad smell out of a hot tub?

To get back the refreshing smell in your hot tub, try shocking your tub to kill contaminants. Cleaning the tub properly might be a better option, although you will have to drain the water entirely before doing so to get the work well done. Some people opt to use spa packets to cross from smelling clean to smelling amazing.

You can get doable scented sanitizers in the market, especially around aromatherapy spa items. Only make sure you double-check so you are not in for unwanted surprises. In the long run, the only way to keep your hot tub in perfect condition is by maintaining its pH levels, observing proper hot tub hygiene and maintenance.

Editorial Staff

I'm Adnan Sabanovic, the guy behind Hot Tubs Report. I've had a chance to enjoy hot tubs last few years and have really become interested in owning one of them. Nearly every weekend you'll find me spending time with my family or playing sports. If I am not doing that then I'm here writing about tubs on Hot Tubs Report. This blog is a research for my first hot tub which I decided to document and share publically so others can benefit from it as well.

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