How to Fix Smelly Hot Tub Water

Bad smelling hot tub water can came on gradually or happen without warning and suddenly start emitting fishy, metallic, musty, sewage or sulfur smells. Foul water can occur a few reasons that all have to do with not performing regular water tests and treatments. Failure to properly maintain hot tub water quality can result in bacteria or algae growth or and unbalanced pH levels that can cause bad odors.


Causes of Foul Smelling Hot Tub Water

Standing water takes on a bad smell due to contaminates that can cause the pH level to become too high or too low or results in the growth of algae and/or bacteria because the sanitizer level is too low. Contaminants can include body oils, suntan lotion, colognes and other body products that bacteria and algae use for food. Simple airborne particles, like dust and pollen, carry bacteria that can breed in water that does not contain enough sanitizer to kill the microorganisms.

There are thousands of different types of bacteria, some harmful and some beneficial. Food particles are a prime source of bacteria growth that can give water a strong sulfur, or rotten egg smell.

Learn how to fix smelly hot tub odor smells.

While the types of bacteria that inhabits pools and spas is not usually dangerous, it can produce very bad odors as it breaks down organic matter. While the bacteria itself may not be harmful, it can result in hydrogen sulfide gas escaping from the water that can cause nausea, headaches and even convulsions. The bacteria that causes hydrogen sulfur odor can also allow the growth of other harmful elements such as iron bacteria that can clog plumbing systems. Like bacteria, there are also a variety of algae species that can result in bad odors as it breeds.

Correcting Foul Smelling Hot Tub Water

Before the problem can be corrected it first has to be diagnosed and this means testing the pH and sanitizer levels. Test kits are available at all pool and spa supply outlets as well as most big box and hardware stores. The water’s pH levels should fall between 7.4 to 7.6 parts per million with a total alkalinity level of 100 to120 parts per million and the chlorine level should be between 2 to 4 parts per million. If any of these numbers are off, the levels need to be adjusted back to the proper places.

Correcting foul smelling water is accomplished by adding sanitizing tablets or granule and pH increaseer or decreaser to the water by following the instructions on the products. If balancing the pH of the water and increasing sanitizer levels does not eliminate the smell, then the source of the foul smell is either bacteria or algae buildup, or both. To correct this add 1 ounce of a natural enzyme spa treatment per 250 gallons of water to kill off the bacteria and algae.

If the water still has a foul smell after executing all of the above treatments, you will have to drain and clean the hot tub and refill it with fresh water.

Execute the following steps to balance the hot tub water:

  1. Test the water pH and alkalinity levels with test strips from the testing kit.
  2. If water isn’t balanced, fix the alkalinity levels first and then balance the pH levels. Add an alkalinity increaser if the alkalinity level is low. As there is no such thing as an alkalinity decreaser, add a pH decreaser to reduce the alkalinity level.
  3. Add a pH booster if pH levels are low or a pH decreaser if the pH is too high.
  4. Analyze and balance sanitizer levels and add chlorinating tablets or granules.

While it is not a common occurrence, bacteria can also gain a foothold inside of pipes and hoses if the hot tub is not used for extended periods of time. If all else has failed to remedy the odor problem, you may need to clean the inside of the water supply pipes and hoses.

Preventing Foul Smelling Hot Tub Water

As the old saying goes, an ounce of prevention is worth a pound of cure. The best solution to keeping your hot tub water from developing a bad smell is to keep the water clean and balanced. This means regular maintenance of the hot tub that includes testing the water pH, alkalinity and sanitizer levels at least once a week and cleaning the filter once a month.

Everyone should thoroughly shower before getting in the spa to remove all body contaminants. Do not eat in or near the spa to keep food particles out of the water. Finally, keep your hot tub covered when not in use to cut down on airborne contaminants entering the water.