Total Dissolved Solids in Swimming Pools

Understanding Total Dissolved Solids (TDS)

Total Dissolved Solids (TDS) refer to the sum of all inorganic and organic substances dissolved in water, including minerals, salts, and metals. In the context of swimming pools, TDS levels are a critical parameter for maintaining water quality and ensuring a safe and enjoyable swimming environment. These substances can originate from various sources, including chemicals added for water treatment, swimmer waste, environmental debris, and even the water supply itself.

Sources of Total Dissolved Solids in Swimming Pools

Chemical Additives

Swimming pool maintenance involves the regular addition of chemicals such as chlorine, bromine, algaecides, and water balancers. Over time, these chemicals break down and contribute to the overall TDS levels.

Swimmer Waste

Every swimmer introduces sweat, oils, cosmetics, and other personal care products into the pool water. These contaminants dissolve and elevate the TDS levels, impacting water quality.

Environmental Contaminants

Debris such as leaves, dust, and pollen can enter the pool, especially in outdoor environments. These organic materials decompose and increase TDS.

Water Supply

The quality of the water used to fill and top up the pool also influences TDS. Tap water itself contains varying levels of dissolved solids, which add to the pool’s TDS.

Ideal TDS Levels for Swimming Pools

Maintaining optimal TDS levels is crucial for pool health. Ideally, TDS levels should be kept between 1,000 to 2,000 ppm (parts per million). Levels above this range can lead to several problems, including:

  • Decreased Sanitizer Efficiency: High TDS levels can interfere with the effectiveness of chlorine and other sanitizers, making it difficult to maintain proper disinfection.
  • Cloudy Water: Elevated TDS can cause the water to become cloudy, reducing its aesthetic appeal and potentially indicating imbalanced water chemistry.
  • Scaling and Corrosion: Excessive TDS can lead to scaling on pool surfaces and equipment, as well as corrosion, which can damage pool infrastructure.
  • Eye and Skin Irritation: High TDS levels can cause discomfort for swimmers, leading to eye and skin irritation.

Measuring TDS in Swimming Pools

Regular testing is essential to monitor and control TDS levels. TDS meters, which measure the electrical conductivity of the water, are commonly used for this purpose. These meters provide a quick and accurate reading of the TDS levels, allowing pool operators to take necessary corrective actions.

Managing High TDS Levels


The most effective way to reduce high TDS levels is through dilution. This involves partially draining the pool and refilling it with fresh water. The fresh water has a lower TDS concentration, which helps to bring the overall TDS levels within the desired range.

Reverse Osmosis

Reverse osmosis (RO) is a more advanced and efficient method for reducing TDS. This process involves passing the pool water through a semi-permeable membrane that removes dissolved solids. RO can significantly reduce TDS levels without the need for draining and refilling, making it an environmentally friendly option.

Regular Maintenance

Preventive measures are key to keeping TDS levels in check. Regularly cleaning the pool, maintaining proper chemical balance, and controlling the introduction of contaminants can help manage TDS effectively. This includes routine vacuuming, skimming, and using pool covers when the pool is not in use.

Impact of High TDS on Pool Equipment

High TDS levels can have a detrimental effect on pool equipment. The dissolved solids can accumulate in filters, pumps, heaters, and other equipment, leading to reduced efficiency and increased wear and tear. Regular maintenance and monitoring of TDS levels can help extend the lifespan of pool equipment and reduce the need for costly repairs.


Total Dissolved Solids (TDS) are a critical factor in maintaining swimming pool water quality. By understanding the sources and impacts of TDS, pool operators can take proactive measures to monitor and control these levels. Regular testing, dilution, and advanced methods like reverse osmosis can effectively manage TDS, ensuring a safe, clean, and enjoyable swimming experience. Proper management of TDS not only enhances the swimmer’s experience but also protects the pool infrastructure and equipment, leading to long-term savings and sustainability. Maintaining optimal TDS levels is a vital aspect of pool care that should not be overlooked.