THE WASHINGTON POST – Plop. Fizz. Relax. Adding a fragrant bath bomb to your tub can transform a routine wash into a relaxing, spa-like soak.
Although these popular bundles of stress reduction are especially welcome these days, they can pose problems for your plumbing. But not all bath bombs are bad; it depends on what’s in them and how you use them.
Director of the health, beauty and environmental sciences lab at the Good Housekeeping Institute Birnur Aral walked me through this quick science lesson.
Basically, two ingredients make bath bombs fizz: baking soda (sodium bicarbonate) and citric acid.
When an object combining them is dropped into warm bath water, you witness an acid-base reaction between the two, and CO2 (carbon dioxide) gas is released, causing the fizz and foam.
Think of it as a less-volatile version of that third-grade volcano science project, where you mixed baking soda and vinegar.
In theory, baking soda, citric acid and the salts are all water-soluble, Aral said.
“But since we are dealing with added ingredients, such as the oils, it is possible that some of these only get partially dissolved in the bath water,” she said. “I think the biggest culprit is titanium dioxide, which is insoluble in water.
“Though this is a minor component in these formulas, it is possible that over time, it can get accumulated in the nooks and crevices of your pipes or mingle with other debris, such as hair and dead skin that gets sloughed off, and contribute to clogs,” she said.
One total no-no: bath bombs and jetted tubs. Mulder said this is a recipe for disaster.
Hot tubs and spa-like tubs use a pump to suck water into and force water out of their jets.
“These systems can’t really filter foreign material found in a bath bomb,” he said. “If you damage the main pump system, you may have to pull out the entire tub – a costly consequence.”
This isn’t to say that bath bombs are taboo. You just have to be smart when using them.
Even Mulder lets his young daughter indulge. “Anything that helps me get my five-year-old into the tub is a plus,” he said.