The District began to purchase water from the City of Houston in the forth quarter of 2006, in order to comply with the groundwater reduction requirements of the Harris-Galveston Coastal Subsidence District. This infusion of City water into the Districts water supply system required the treatment of all District water with chloramines, the same treatment process used by the City. This made our water supply compatible with City water and minimized transitional water quality issues associated with this transition. Please review the information on Chloramines below.

While chloraminated water is completely safe for people to drink, bath in, clean scrapes or cuts, cook, water the garden, and for most other purposes, there are noteworthy consequences associated with this conversion to chloramine treatment for three special groups which will require precautionary measures.

Kidney dialysis patients, aquarium/pond owners and certain businesses or industries that use water in their treatment process will need to remove chloramines prior to use.

Dialysis Patients.

Like chlorine, chloramine can harm kidney dialysis patients during the dialysis process if it is not removed before the water mixes with the bloodstream. People and animals that do not live in water can safely drink chloraminated water because the digestive process neutralizes chloramine before it enters the bloodstream. Two methods are typically used to remove chloramine from water before dialysis. These methods involve either the use of ascorbic acid or a granular-activated carbon filtration system specifically designed to remove chloramines. Home dialysis patients should work with their home dialysis facility and physician to make necessary adjustments to their equipment

Aquarium/Pond Owners.

Chloraminated water passes through gills, directly entering the bloodstream of fish, amphibians and reptiles. Chloramine must be removed as it binds to iron in red blood cell hemoglobin, causing reduced cell capacity to carry oxygen. Unlike chlorine which over time tends to dissipate out of water, chloramines do not and as a consequence remain toxic to aquatic species (fish, frogs, snails, turtles, etc.) unless removed by treatment or filtration. Treatment products (liquid and tablet) are available at fish and pet supply stores and aquarium or ponds supply professionals. It has been reported that high quality activated carbon filtration and reverse osmosis remove chloramines under optimum conditions, but are expensive and must be closely monitored to ensure their effectiveness.

Certain Businesses.

Businesses using highly processed water may need to remove chloramines from water prior to use Restaurants or seafood suppliers with fish tanks, beverage manufacturers, labs and high tech operations are examples of businesses that should review current operations and take steps to ensure their water is treated appropriately for use. Chloramine may require your company to adjust or upgrade its current filtration and treatment system. A water treatment professional or your equipment supplier can answer questions about how chloramines will impact your current system, and recommend solutions to fit your business needs.

About Water Disinfection

Water disinfection with chlorine has been extremely successful in protecting water from bacterial and viral contamination and has virtually wiped out water-borne diseases like typhoid fever, cholera, and dysentery. Chlorine however, may introduce a potential health risk, particularly when used to treat surface water where not all organic matter may be filtered out before entering the distribution system. When chlorine is added to the water it not only kills bacteria and viruses but also reacts with other chemicals found in the water and form new compounds known as disinfectant by-products (DBP). One group of DBP, trihalomethanes (THM), is a suspected carcinogen and may pose other long-term health effects if present at high levels. THMs are not present at high levels in the District=s water supply and distribution system. The conversion to chloramination mitigates the risk of THM in the Districts water supply and distribution system.

Form of Notice.

Harris County Municipal Utility District No. 23 has changed the disinfectant that we use from Chlorine to chloramines. The change is intended to benefit our customers by reducing the levels of disinfection byproducts (DBPs) in the system, while still providing protection from waterborne disease.

However, 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 chloramine prior to this date. Medical facilities should also determine if additional precautions are required for other medical equipment.

In addition, 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.

The foregoing is the form of notice prescribed and required by the Texas Commission on Environmental Quality to be issued by the District prior to conversion.