Purple means ‘Don’t drink the water’
: As I was walking our dog on Kahaloa Drive in Manoa, I noticed that in addition to the existing color of yellow on the fire hydrant, there is now also a bright purple color painted on it. The corresponding manhole also has the same colors. Has the fire department changed its color code and why?
Answer: The Board of Water Supply, not the Honolulu Fire Department, is responsible for inspecting, maintaining and repairing the more than 20,300 municipal fire hydrants on Oahu.
Some hydrants are trimmed in light purple to flag discharges of nonpotable water, explained agency spokeswoman Su Shin. She said the color purple has been used since about the year 2000.
Among water agencies, "purple is the universal color for nonpotable water," signifying anything from recycled to brackish water, basically "anything that isn't meant for human consumption," she said.
It is used for irrigation, for example, as well as in fire protection.
In Hawaii, most of the water from fire hydrants is potable, Shin said. If you see a plain yellow hydrant, that means the water it discharges is drinkable.
While there is no universal standard for the color of hydrants -- on the mainland, they may be red, black, silver, etc. -- yellow was chosen here for all municipal hydrants because of its high visibility.
But that wasn't always the case. Prior to the early 1970s, municipal hydrants here were painted silver, Shin said.
According to the National Fire Protection Association standards, fire hydrants should be painted "chrome yellow," but it will accept other colors if they were already in use when yellow was adopted in the 1970s.
You might see nonyellow hydrants because not all hydrants on Oahu are under the jurisdiction of the Board of Water Supply. The military, for example, has its own hydrant system and "can paint (their hydrants) whatever color," Shin said. The Air Force has chosen brown, she noted.
New residential communities, such as in Kapolei and Ewa, were required to install dual pipeline systems to separate the fire protection system from drinking water, Shin said.
"That's why in those areas, we can service recycled water to golf courses and for common areas like parks, medians, freeway overpasses, fire hydrants," she said.
In most of the older communities, such as Manoa, that dual system was not installed initially. The Board of Water Supply did so to keep the potable and nonpotable water separate, which meets Environmental Protection Agency standards, she said.
So "in that small area for Manoa, there is a nonpotable water used for nonpotable use," she said.
You can find all sorts of interesting information about hydrants at firehydrant.org, which says it is "the Web's first attempt to bring together the technical aspects of hydrants along with historic preservation and enthusiast/collector interests."
Got a question or complaint?
Call 529-4773, fax 529-4750, or write to Kokua Line, Honolulu Star-Bulletin, 500 Ala Moana Blvd., No. 7-210, Honolulu 96813. As many as possible will be answered. E-mail to firstname.lastname@example.org
. See also: Useful phone numbers