Why Does My Pool Water Smell Like Sulfur?

A swimming pool can be a worthwhile addition to any home, but the necessary use of chemical treatments used to disinfect pool water carries with it some important considerations and responsibilities. Regularly exercising preventive maintenance and using all your pool hardware ensure proper disinfection of pool water.

Another important part of maintaining your pool is to know how to spot potential problems that could lead to hazardous or unsanitary conditions. A sulfurlike or rotten-egg smell emanating from your pool water could be an indication of any of several different problems.

Hydrogen Sulfide

When it comes to a rotten-egg smell, the most likely culprit is hydrogen sulphide, a chemical that results from decomposing organic matter and other sources. In addition to the offensive odour, hydrogen sulphide can corrode iron, steel, copper and brass with which it comes into contact. It is also very flammable and very poisonous to humans. Clearly then, quick removal of hydrogen sulphide is important to the safety of the people using your pool. The first step is to identify the source of the smell.

Common Causes of Hydrogen Sulfide in Pools

Hydrogen sulphide may be an indication of the presence of sulphur-reducing bacteria that feed on sulphur and other sulphates and convert them to hydrogen sulphide gas. To test for this, use a commercially available water test like the Hach Pathoscreen Medium. Simply follow the manufacturer's directions for gathering a water sample and see if the test indicates the presence of hydrogen-sulphide-producing bacteria. These bacteria love an oxygen-deprived environment, so check all parts of the water pump system that are sealed off and do not receive regularly circulating air.

How to Treat

There are several ways to remove hydrogen sulphide, and the bacteria causing it, from swimming pool water. Since the bacteria cannot thrive in an oxygen-rich environment, aeration is effective at killing the bacteria. Adding extra chlorine temporarily (a so-called "shock treatment" chlorination) can raise oxygen levels enough to kill the bacteria. Potassium Permanganate is also an effective aerator for swimming pool water. Adjust the pH level of the pool water below 7 prior to aeration.

Other Considerations

It is impossible to overstate the importance of consulting a professional before using any potentially hazardous chemicals in your pool water. If you'd rather not have to handle dangerous chemicals on your own, contact local pool cleaning services and see if they offer a cleaning technique that removes hydrogen-sulphide-producing bacteria from pool water. Make sure no one uses the pool at any time while treating its water for a possible bacterial infection.