Chloramines from tap water

  02/26/2013 at 08:36 am

Chloramines from Chloramation of Tap water

This information describes the chloramination process for tap water, the reasons for chloramination, and the impact of chloraminated water on pools and spas.
Many pool and spa operators understand that the primary source of combined chlorine in pools and spas is from the reaction of chlorine sanitizer with bather perspiration and waste; however, another potential source is chloraminated tap water, which may be used for fill and make up water. When pool and spa operators use tap water to fill pools and spas, they may be adding considerable concentrations of combined chlorine.

Chloramination is a process that mixes free chlorine (usually chlorine gas) and ammonia to form chloramines. The process is often used by water treatment authorities to treat drinking water. EPA estimates that over 50 percent of large systems serving at least 10,000 people use chloramination.

Pools and Spas. The combined chlorine in pools and spas is a combination of inorganic chloramines (monochloramine and dichloramine), organic chloramines (chlorinated creatinine, chlorinated uric acid), and other chlorinated organic waste materials. Monochloramine can be effectively removed by chlorine. It is difficult, however, to remove organic chloramines.


Fresh Fills. If possible, it is best to avoid using chloraminated tap water for fresh fills of pools and spas. If you must use chloraminated water as fill water, take the following remedial steps after filling the pool or spa: (1) If necessary, adjust the pH up to 7.4-7.8 and (2) oxidize the pool/spa using a non-stabilized chlorine oxidizer at 5-10 times the
combined chlorine concentration to achieve an acceptable concentration less than 0.2 ppm. Make up Water. Make up water is water that is added to a pool or spa to replace water that has been lost from evaporation, splash out, or backwashing. Make up water will not add significant concentrations of combined chlorine. When chloraminated make up water is added to a pool, the impact is much less than when chloraminated water is used to fill a pool. This impact may be of importance only to operators of pools with high bather loads, where compliance with the maximum combined chlorine concentration is difficult. After adding make up water, the pool water should be tested to determine the concentration of chloramines. If the combined chlorine concentration is unacceptable, the chloramines concentration can be reduced by adjusting the pH to 7.4-7.8 and oxidizing with non-stabilized chlorine at 5-10 times the combined chlorine concentration. After the desired combined chlorine concentration has been attained, balance the pH and alkalinity.
By Darrin Downing