How to Clean the Piping System for a Whirlpool Tub

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Whirlpool tubs are valuable additions to your home but they must be cared for properly to ensure that the piping system does not contain high levels of bacteria which can pose a serious health risk to you and your family.

Whirlpool tubs have become increasing popular in new homes and also in remodelling and renovations to bathrooms. While they can add to the resale value, they also require more maintenance and upkeep than a traditional bathtub and shower. The National Association of Home Builders (NAHB) conducted a study in 2007 and determined that the average life expectancy of a whirlpool tub is 20-50 years for the fixture, not the circulation system. The life expectancy of the circulation system which includes the pump, fittings, and piping, will vary depending on the amount of use. The issue with whirlpool tubs is that the circulation system is difficult to access and water trapped in the system after each use provides the perfect environment for bacterial growth.

This article deals with residential whirlpool bathtubs that are filled and drained after each use, as distinguished from recreational spas and hot tubs found in hotels, spas, and health clubs.

Study of Life Expectancy of Home Components

Whirlpool Tub Maintenance

Each use of a whirlpool tub exposes the circulation system to residue which accumulates on the inside lining of the piping and fittings that supply water to the jets. If the system is not properly maintained, the incoming water can become contaminated when the jets are turned on and could cause bacterial infection or serious illness.

Typical Circulation System

Most manufacturers recommend avoiding oil-based soaps, bubble bath soaps, and bath and mineral salts is an important part of preventative maintenance. Avoiding these products will eliminate potential pump issues and ensure that an excessive amount of residue is not sticking to the interior walls of the piping. Depending on its use the circulation system should be flushed of these contaminants monthly or, if possible, after each use.

To date, no whirlpool tub design or procedure has been developed that can ensure a circulation system is completely flushed and entirely cleaned. This does not mean that these fixtures should not be cleaned and there are specially formulated commercial cleaning products available or you can use household cleaning products to limit bacterial growth.

Commercial Whirlpool Piping Cleaner

Laboratory Study

Recent reports of whirlpool-associated septicemia, skin infections, urinary tract infections, pneumonia, legionellosis and Pontiac fever have raised serious public health concerns about the risks associated with whirlpool bathtubs.

Even when a whirlpool tub is drained after use, the circulation system itself does not fully drain. The industry standards committee of the American National Standards Institute has adopted a standard that permits the typical circulation system to retain over 10 fluid ounces of dirty bath water when the bathtub is fully drained. Stagnant bath water trapped inside a system already rich in biofilm provides an ideal environment for infectious bacteria to flourish.

Whirlpool bath samples were collected from all over the United States from both private homes and hotels, and were subjected to bacterial analysis. One container of tap water was collected after the tap was allowed to run for 1-2 minutes and four containers of tub water were collected after a clean tub was filled and the jets were engaged for 2-3 minutes. Bacteriological examination of the water involved incubating specimens on agar pour plates of water dilutions to assess relative bacterial numbers and examining the samples to determine the type of bacteria found in the piping system.

Findings indicate that, as compared to tap water samples, the bacterial numbers were greatly increased in the whirlpool tub samples (253 cfu/ml vs. 3.08 x 10 to the 6th power cfu/ml, respectively, P <0.002)(See Table 1.) Normal tub water samples were not significantly different from tap water samples. Additionally, all whirlpool tub samples yielded microbial growth, whereas 72% of the tap samples showed no growth under the experimental conditions used in this trial. No data correlating the number of viable organisms in water with the risk of acquiring infection is currently available. However, the analysis of 100-ml filtered samples yielded TNTC (too numerous to count, or >300 cfu) in 61% of the tub samples tested, indicating that the bacterial load for a 100-ml sample was fairly high in a majority of cases.

How to Clean Whirlpool Tub Circulation Systems

To perform treatment with a household remedy, ensure that jets are adjusted to limit any air induction.

1. Fill the whirlpool tub with hot water to an appropriate level (2" above the highest jet).

2. Add two to four tablespoons of low-foaming dishwasher detergent.

3. Open air induction to the maximum and run whirlpool jets for 10 to 20 minutes.

4. Drain the tub completely.

5. Again, close air induction and refill tub with hot water to an appropriate level and then add one cup of household bleach.

6. Re-open air induction to the maximum and run whirlpool jets for 10 to 20 minutes.

7. Drain the tub completely and refill with cold water.

8. Drain and rinse off the tub surface.

Residue accumulation or scale deposits may persist on the interior walls of the piping, even after cleaning. You should consider having the whirlpool tub cleaned professionally on a yearly basis. A professional cleaner should flush, descale, and disinfect a whirlpool circulation system.

Hygienic Systems

Newer whirlpool bathtubs that have hygienic systems as part of the circulation system may not require the maintenance mentioned above. Hygienic systems clean bacteria as required by the National Sanitation Foundation (NSF) in Standard 50 for pools and spas. These systems typically have a port for adding cleaning solutions and controlled mechanics that allow a user to initiate a system flush.

By cleaning and maintaining your whirlpool tub circulation system you will extend the life of the system as well and reduce the likelihood of illness or infections due to water-borne bacteria.