Temporary Conversion to Free Chlorination in Drinking Water Supply

Temescal Valley Customers Drinking Water Notice and FAQs

Beginning the week of April 15, EVMWD will temporarily change the drinking water disinfection process in the Temescal Valley Region. Chlorine disinfection, also known as free chlorination, will replace the current chloramine disinfectant in the water supply. Both chemicals are safe and effective methods of drinking water disinfection approved by the US Environmental Protection Agency (EPA) and the CA State Water Resources Control Board-Division of Drinking Water (SWRCB-DDW) and widely used in public drinking water supplies across the nation.

Precautions must continue to be taken by customers to remove or neutralize chloramines and free chlorine during the kidney dialysis process, in the preparation of water for fish tanks and ponds, and for businesses requiring highly processed water.

Customers may notice EVMWD staff flushing fire hydrants throughout the Temescal region and may notice intermittent and temporary changes in taste, odor and color of their tap water during the conversion period. The free chlorine conversion process  should take two to five days to fully establish.

For any questions or concerns please contact EVMWD at (951) 674-3146 or by email at: OpsDispatch@evmwd.net



1. What is free chlorine?

Free chlorine is a more aggressive disinfectant than chloramines, making it ideal for addressing more
resistant bacteria and viruses.

2. What are chloramines?
Chloramines are disinfectants used in drinking water to keep water safe from bacterial and virus contamination.

3. What is the purpose of converting from chloramines to free chlorine?
EVMWD drinking water supplies in the Temescal Region are primarily obtained from groundwater wells.  Recent testing has shown sporadic low level total coliform bacteria in the well waters.  Although, chloramine disinfection is sufficient treatment for bacteria and viruses, EVMWD is taking extra precaution by converting to free chlorine disinfection to more aggressively treat the water supply.  Additionally, this temporary change in the water treatment process helps prevent bacteria from becoming overly resistant.

4. How long will free chlorine be used in the water system this year?
EVMWD estimates approximately three to six months of temporary free chlorination and until water quality testing confirms suitability for chloramine disinfection.  

5. Will my tap water taste different while free chlorine is used in the water treatment process?
Some customers may notice a slight chemical smell similar to that of water in a swimming pool.  Each
individual customer has his or her own sensitivity level to the taste and/or odor of free chlorine. Many
detect no difference.

6. Is water treated with free chlorine and chloramines safe?
Yes, both are safe and effective.  EVMWD is in regular communication with the SWRCB-DDW and strictly adheres to the State & EPA guidelines on minimum and maximum chlorine levels.  Both forms of chlorinated water are safe for people and animals to drink, for cooking and bathing, watering the garden, and all other common uses.  However, precautions must continue be taken to remove or neutralize chloramines and free chlorine during the kidney dialysis process, in the preparation of water for fish tanks and ponds, and for businesses requiring highly processed water.  A de-chlorination procedure optimized for the removal of chloramines will equally remove free chlorine. 

7. Why are free chlorine and chloramines harmful for dialysis patients?
Both free chlorine and chloramines may harm kidney dialysis patients during the dialysis process if it is
not removed from water before passing into the bloodstream. Like everyone else, dialysis patients may drink water treated with either free chlorine or chloramines because the digestive process neutralizes the chemicals before they enter the bloodstream.

8. Will free chlorine or chloramines affect household plumbing, pipes and/or water heaters?
Some older household plumbing and water heaters may incorporate rubber materials and parts, which
can degrade over time.  Ask for chloramines-resistant parts, which are readily available at hardware
supply stores or from a plumber, when replacing rubber plumbing materials. Chloramines-resistant parts
will be effective regardless of the type of chlorine used.

9. How can I remove chlorine from my water?

Free chlorine can be removed by boiling or adding a bit of lemon juice to your tap water. You can also fill
a container with water and leave it open to allow chlorine to naturally dissipate over a 24-hour period.

10. Will pool owners need to treat water differently?
Pool owners must maintain the same chlorine level in water treated with either free chlorine or
chloramines to prevent algal and bacterial growth. Pool supply stores can provide more information.

11. What does “hydrant flushing” mean?
EVMWD personnel will strategically draw the chlorinated water through selected fire hydrants located all around the service area for several days.  Hydrant flushing also helps to wash out sediments that have collected in water mains throughout the distribution system.  

12. Will I see a drop in water pressure due to the flushing?

Most customers will not see a drop in water pressure. If a change in pressure does occur, it usually lasts
for less than half an hour. If you experience a significant loss of water pressure lasting longer than 30
minutes, please contact EVMWD at (951) 674-3146 or by email at:  OpsDispatch@evmwd.net

13. Will hydrant flushing in my area cause cloudiness or sediment in my water?
Since the flushing process can stir up sediments in water mains, you may notice occasional short-term
Cloudiness, brown/yellow color in your water. If your tap water is cloudy or colored, open your faucet and allow water to flow until the clarity improves. If your tap water remains cloudy for an extended period of time, please contact the EVMWD  at (951) 674-3146 or by email at: OpsDispatch@evmwd.net

14. Where can I get more information?
For answers to any questions related to your water quality, please contact EVMWD (951) 674-3146 or by email at:  OpsDispatch@evmwd.net