Northwest Harris County Municipal Utility District 5 will begin using a different process of water disinfection in your subdivision on or about March 18, 2024. This process involves using chloramines rather than only chlorine as the disinfectant in the water supply.

  1. What is chloramination?
    • Chloramination is the use of both ammonia and chlorine to disinfect water. Ammonia is added to water at a carefully controlled level. The chlorine and ammonia react chemically to produce a combined chlorine residual or chloramines.  Chloramines are safe in drinking water and serve as an effective method of disinfection. In the U.S., many water systems have used chloramination for several decades.
  2. Why is Northwest Harris County MUD 5 converting from free chlorine to chloramines?
    • Northwest Harris County MUD 5 will be receiving surface water on March 18, 2024. Because the surface water is treated with chloramines, Northwest Harris County MUD 5 is required to convert to chloramines so the system is not blending free chlorine and chloramines. Blending can cause inadequate disinfection and aesthetic issues in the water system.
  3. Should kidney dialysis patients take special precautions?
    • The change to chloramines can cause problems to persons dependent on dialysis machines. A condition known as hemolytic anemia can occur if the disinfectant is not completely removed from the water that is used for the dialysate. Consequently, the pretreatment scheme used for the dialysis units must include some means, such as a charcoal filter, for removing the chloramines prior to the conversion to chloramines. Medical facilities should also determine if additional precautions are required for other medical equipment.
  4. Do customers with live fish or aquatic animals need to take special precautions?
    • Chloraminated water may be toxic to fish. If you have a fish tank, please make sure that the chemicals or filters that you are using are designed for use in water that has been treated with chloramines.  You may also need to change the type of filter that you use for the fish tank.
  5. Will I notice a difference in the water?
    • Some customers may notice a reduction in the taste and or smell of chlorine in the water. Customers will see MDS operators in the district flushing hydrants and checking the disinfectant levels in the water. Due to the increase in flushing throughout the district, customers may notice discoloration in the water. This should pass after briefly running your internal faucets.
  6. How can I get more information?
    • If you are experience continued taste or odor issues with your water or would like any more information, feel free to contact the Northwest Harris County MUD 5 Operator, Municipal District Services at (281) 290-6500 or visit should you have a question or comment.