Stillwater News

City of Stillwater switches back to chloramine disinfection process on May 22

Released:May 22, 2017


(STILLWATER, OKLAHOMA / May 22, 2017) – The City of Stillwater transitions back to its traditional chloramine disinfection process on Monday, May 22. The switch from free chlorine to chloramines is estimated to take two weeks.
Use of chloramines was temporarily interrupted in March after the water treatment plant ammonia system required emergency repairs. The City made a temporary switch to free chlorine disinfection and took the opportunity to perform a preventative free chlorine flush of the system.
“This type of flush is conducted routinely at drinking water systems across the nation,” Water Resources Director Bill Millis said. “As always, the water is safe to drink and use.”
Staff monitored residual levels during the process and found improved performance in many areas, indicating a successful free chlorine flush.
“These improvements are expected to reduce the amount of flushing our crews would have otherwise performed during the summer, saving staff hours and conserving water,” Millis said.
Customers might notice changes in taste and odor during the switch. Allowing the water to run through faucets for a short period before use could minimize taste or odor issues. City staff will flush water lines extensively, so some customers might experience periods of low pressure.

If you have additional questions, contact Water Treatment Superintendent Doug Carothers at 405.533.8492.


For media inquiries, contact the Office of Marketing and Public Relations at 405.742.8219 or email

Update on temporary water treatment changes

(Updated May 9, 2017)

The City of Stillwater has been using free chlorine for disinfection of treated drinking water for about seven weeks, precipitated in March by a malfunction of the ammonia feed system, which prevented production of chloramines. Due to several factors, the switch back to chloramines is delayed to late May. With the large influx of visitors to Stillwater in mid-May, and the extensive system flushing required for the chloramine switch over, the City wishes to minimize the inconvenience to our customers.
While the majority of Oklahomans are served by drinking water systems that use chloramines, these systems represent a small percentage of the total number systems in the state. Only about 20 of the 1,670 drinking water systems in Oklahoma, mostly the larger systems, disinfect with chloramines. Most of the others use free chlorine.

If you have additional questions, contact Water Treatment Superintendent Doug Carothers at 405.533.8492.


(Updated March 27, 2017)

Equal treatment? City officials say temporary change to chlorine doesn’t affect water safety (Stillwater News Press)


City officials say temporary change to chlorine doesn't affect water safety

Michelle Charles CNHI News Oklahoma

STILLWATER – At least one Stillwater resident seems unfazed by the noticeable scent of chlorine emanating from the city’s tap water since last week.

In a Facebook post on the Stillwater Community Watch page, James Hall reported his 4-year-old son saying, “My bath smells like the YMCA pool ... I like it!”

Dad wasn’t as excited.

“I don’t want to drink ANYTHING that smells like the YMCA pool …,” Hall added.

People complained throughout the weekend about the taste of their drinking water.

Then environmental activist Erin Brockovich ratcheted up the level of concern Sunday when she called the City of Stillwater out on her Facebook page with accusations of irresponsible actions and lying to the public.

Brockovich assumed the city was doing a systemwide chlorine “burnout” needed to combat nitrification, a reaction between ammonia and microbes that degrades water quality in systems that, like Stillwater, disinfect with chloramine, a combination of ammonia and chlorine.

Operators of affected systems switch to free chlorine – chlorine that isn’t combined with anything else – to combat nitrification.

Stillwater officials say Brockovich made an incorrect assumption.

The switch to free chlorine wasn’t in response to a water quality problem, Water Resources Director Bill Millis said.

It became necessary when a piece of equipment that injects ammonia into the system malfunctioned Wednesday at the water treatment plant. After investigating options for getting the chloramine system working again, water department staff realized that wasn’t going to happen quickly.

City Manager Norman McNickle said the city wasn’t required to, but Millis chose to report the issue to the Oklahoma Department of Environmental Quality and consult with the agency on the best course of action.

The water department chose to go with free chlorine and while it was at it, take the opportunity to do a modified preventative burnout and flush the system, Millis said.

“In a rough sense, that's what we’re doing,” he said. “... We didn’t do this because of nitrification … It provided an opportunity to do what is a best practice.”

The process will last for an estimated two to three weeks.

The more highly chlorinated water now has to work its way through the entire system and the water department is hastening that process by flowing water from hydrants and other methods.

“Our testing indicates it’s pretty well distributed throughout the system,” Millis said. “There may be some places at the end of lines it hasn’t hit yet.”

He says he can see why people would notice a difference in the taste or smell of their water but the levels of chlorine are within Environmental Protection Agency and ODEQ defined safe levels.

“It’s highly chlorinated relative to where it was,” Millis said. “Just switching from chloramine to free chlorine might make a difference ... When you first switch you want to raise it a little higher.”

He says the chlorine levels will dissipate over time, and within the next few days people should notice it less and less.

Millis recommend people bothered by the taste let the water run for a few minutes before drinking it or fill a pitcher and put it in the refrigerator because chlorine oxidizes over time, reducing the amount in the water.

A carbon filter, either on the faucet or in a pitcher will also help.

City Councilor Will Joyce took exception to the charges leveled against the city by Brockovich.

He said Brockovich has no firsthand knowledge of the city’s water system or treatment process.

“For her to be ascribing malicious intent, it’s just not helpful,” Joyce said. “And it’s unfortunate that someone with that kind of following would jump to conclusions.”

Joyce urged any water customer with questions or concerns to call the water department.

“Ask questions,” he said. “You can go tour the plant.”

Multiple attempts were made to contact Brockovich, but she had not responded by press time.


Story originally published at

Water treatment changes may result in temporary changes in water taste, odor


(STILLWATER, OKLAHOMA / March 24, 2017) – City of Stillwater water customers might notice a change in the taste or smell of their drinking water. This is due to the City needing to make a temporary change to our disinfection process.

“The water remains safe to drink, despite possible changes in taste or odor,” Water Resources Director Bill Millis said. “Allowing the water to run through your faucets for a short period prior to use may minimize any taste or odor issues.”

Water systems around the country periodically make this temporary change from chloramines to free chlorine. The City will switch back to the disinfection method our customers are familiar with (chloramines) in the near future.

If you have additional questions, contact Water Treatment Superintendent Doug Carothers at 405.533.8492.


For more information, contact the Office of Marketing and Public Relations at 405.742.8219 or email


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