Splotch of Green Hair

Woman with short graying hair
Q: My sister-in-law has a thick head of graying hair. The problem is that she has a patch of green hair on the top of her head. She keeps her hair short and styles the top with a curling iron almost daily. She has it trimmed regularly too. It doesn't look too bad until she goes into the sunlight, then it looks bad. Her husband removed the only copper pipe in their plumbing and it hasn't changed. Her water is the same (I believe) as it has been for years (25) and is ground water.
She lives in upstate NY where there is an abundance of good quality unfiltered drinking water. She washes her hair every day. Since it is n ot chlorine and the copper has been removed (which was there for the past 20 years...) what could be causing this unsightly splotch of green hair? Or is that small part of copper pipe really the blame? And if it was, how long before the green goes away? It's pretty concentrated on the top of her head, by the crown of her scalp. It's the gray that is green.
She doesn't color her hair and she's not a blond. She isn't swimming in any pool and the copper pipe is gone, now what? Tried the lemon juice, trying the swimmer shampoo and is thinking about detox next? What do you think? We are searching for any help short of shaving her head. She is reaching that point. Thanks for your time.

A: There are a lot of questions here that have to be answered before I could even hazard a guess as to a possible cause.
These questions include: “Is the green color isolated to the patch of green, or is it simply that the color is more prominent and concentrated in that area?”; “Is your sister-in-law taking any medications or over-the-counter herbal/vitamin supplements?” and “Has the water itself been tested for mineral or chemical residue?” (This can often be done by contacting your county extension office.)
A detoxifying or clarifying shampoo may help, depending on the source of the discoloration, but the better option - particularly since I cannot actually visually inspect the hair to make any kind of assessment – is to visit your local salon to have a professional stylist have a look.
Aside from using the clarifying/detoxifying shampoo the only other idea that comes to mind for dealing with this is to use a color service to try and neutralize the green tones of the hair’s discoloration. This would be done by selecting a hair color formula as pale as possible that uses a red color base.
The idea is that you – more or less – go blonde and in the process, neutralize the green. The downside is that you are committing to using a hair color, although you might be able to find an acceptable shade in a demi-permanent color (which will wash out in 6-12 shampoos) leaving you able to disguise the discoloration without a permanent color commitment.
Photo: Irina Bg/Shutterstock
See also:
Hair and hard well water
The use of clarifying shampoo
How medications can affect your hair and hair color