Sample Customer Notifications

Sample Language for Notifying Customers That Your PWS Is About to Change Residual Disinfectant from Free Chlorine to Chloramines

On , the will be changing the disinfectant that we use from chlorine to chloramines. This 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.

Sample Language for Notifying Customers That Your PWS Is About to Change Residual Disinfectant from Chloraminesto Free Chlorine

On , the will be changing the disinfectant that we use from chloramines to free chlorine as part of our maintenance programto assure the highest quality of drinking water is delivered to your home. Flushing of the distribution system will also occur during this maintenance work.

During this time you may notice a chlorine odor in your drinking water. You may also experience periods of discolored water as a result of the flushing. You can help alleviate this discoloration by turning on your faucets and running the water until it clears.

Water customers should be aware that residual traces of ammonia and chlorine must be removed from the water prior to its use in fish aquariums and ponds, kidney dialysis and some commercial manufacturing of food and beverage.

Kidney dialysis patients should follow your doctor’s recommendations. Medical centers that perform dialysis commonly remove the chloramines or chlorine that enters the dialysis machines. You should consult your physician if you have any questions or concerns regarding the use of water for dialysis.

Please contact at for further information or with any questions. You will be notified prior to the change back to chloramines.

Guidelines for Distribution Transition from Chloramine to Free Chlorine

Pre-Transition Strategy

It is recommended that you notify the IDNR field office prior to switching disinfectants.

Sample for all required monthly bacteria samples

Check date for and if needed, sample quarterly TTHM & HAA5 samples

Coordinate with water plant and plant customers:

  1. Set start date (weather conditions taken into account, i.e., freezing temperatures).
  2. Discuss notification of customers (newspaper, radio, television, hand-outs).
  3. Discuss process of free chlorine entering each system (start tank levels, average daily demand for each system, and maximum production for the water plant).
  4. Discuss approximate time needed to accomplish goals (dependent on length of distribution system, severity of bio-mass and tuberculation intrusion).
  5. Provide contact information for all involved.

Each entity involved should:

  1. Evaluate system for areas of consistently low residuals, areas of steel, cast, or ductile iron mains, areas with a history of particulates or taste and odor complaints. In these areas:
  2. Designate and identify sampling sites (bacteria sample sites, fire hydrants,

or any point that is representative of the problem area.

  1. Take a free and total chlorine residual at each site.
  2. At each site, take a sample to be analyzed for ammonia, nitrites and nitrates.

*A comparison of the sampling site ammonia, nitrite, and nitrate results in the system versus the values at the treatment system entry point will indicate the areas of concern.

  1. Depending on the size of the system, a map can be formulated dividing the system into specific areas. During the flush process, staff can be designated for a specific area. This will reduce response time to address customers’ concerns of water quality and will increase staff productivity.
  2. Determine the location of larger mains originating from the entry point.
  3. Contact industries, businesses, and health care facilities that will or might be affected by the change to free chlorine. These include hospitals, renal dialysis centers, laundries, and fish breeders. Personal contact and communication with those affected via telephone is preferred.
  4. Ensure the necessary equipment, chemicals, log sheets, and personnel will be available when the transition to free chlorine begins. Some suggested stock items are free and total chlorine reagents (for colorimeters and Cl-17s), fire hydrant wrenches, fire hydrant diffusers, dechlorination equipment, valve keys, safety vests, traffic cones, and an adequate supply of main repair parts. Maximum personnel should be available.

Transition to Free Chlorine Strategy

Water Plant Activities

  1. At the beginning of free chlorine feed, have clearwell and supply storage tanks at lowest possible level.
  2. Once the free chlorine is present throughout the plant, the clearwell, and supply storage tanks, keep all the levels as high as possible during the entire shock period. This will ensure adequate supply for consumption and flushing demand. Also, the high levels will maintain the levels in any distribution elevated tanks that “float” with the supply tank.
  3. Maintain the chlorine residual as close as possible to 4mg/l at the distribution entry point.

Distribution Activities

At the beginning of the free chlorine feed, communication with the treatment plant is important.

  1. When the plant’s tanks have made the transition to free chlorine, the distribution storage tank levels should be at the lowest possible level. This allows the distribution storage tanks to more quickly make the transition to free chlorine.
  2. The larger mains at the entry point, which were identified during the pre-transition period, should be the first ones to flush. As the free chlorine enters the system, fire hydrants can be flushed along or at the ends of these mains to initially pull the free chlorine into the system. Log the location, start and finish time, and free and total chlorine residual at each flush point. Use diffusers to reduce damage caused by flushing. Be aware of where the water is flowing to eliminate damage to property. Dechlorination procedures should be followed to ensure no chlorinated water reaches a water of the state.
  3. After the free chlorine is in the system, the areas of concern that were identified during the pre-transition period should be addressed during the first day(s). This enables staff to return to these areas, which may need more attention than other, newer areas of the system.
  4. Areas should be flushed using a directional flush with a high velocity until there is no biomass observed. Measure free chlorine at 30 s, 1 min, 2 min (same sample, just leave it in instrument and hit read at designated times). If free chlorine value continues to increase with each read, the system is not at breakpoint yet and flushing needs to continue. Free chlorine must be stable and within 20% of total chlorine to demonstrate that breakpoint chlorination has been achieved.
  5. Daily, staff should be assigned areas of concern. Small scale distribution maps are good record tools for each crew. Log the location, start and finish time, and free and total chlorine residual at each flush point each time flushing occurs. Use diffusers to reduce damage caused by flushing. Be aware of where the water is flowing to eliminate damage to property. Dechlorination procedures should be followed to ensure no chlorinated water reaches a water of the state. When the directional flush is complete, (i.e., no biomass visible and free and total chlorine values within 20% of each other) return all valves to their normal position. On the area map (formulated during pre-transition period) mark and record the flushed main and continue the process in the assigned area. Depending on the length and configuration of the distribution system, it may take two to four weeks to establish stable free chlorine residuals.
  6. High traffic areas (i.e., downtown, restaurants, schools) should be assigned to a designated crew for after-hour and/or week-end flushing.

Post-Transition Strategy

  1. When the distribution staff has flushed the entire system of biomass and obtained stable free chlorine residuals that are within 20% of total chlorine residual values, the free chlorine disinfection should be maintained for 2 to 4 weeks. After this period, the operators should communicate with the treatment plant and initiate the transition to chloramines. Be sure to notify all industries, businesses, and health care facilities that will or might be affected by the change to chloramine. These include hospitals, renal dialysis centers, laundries, and fish breeders. Personal contact and communication with those affected via telephone is preferred.
  2. As the chloramines begin to enter the distribution system, have all storage tanks at the lowest possible levels and flush the ends of the large mains from the entry point. This will more quickly reintroduce chloramines into the system. Flushing should be done to move the chloraminated water into and through the system. Utilize the same precautions as when making the switch from chloramines to free chlorine.
  3. After chloramines are re-established as the system disinfectant, resample each site designated and sampled during the pre-transition period. A comparison of the pre-and post-transition residuals, ammonia, nitrites, and nitrates will demonstrate the success of the free chlorine transition.
  4. It is recommended that IDNR be notified of the return to chloramines.
  5. Record any staff observations of the process to be used to improve the process in the future.