What can you do if someone is getting Static Electricity Zap while in the Shower when she touches the knob? How can you eliminate the static Zap?

Something's not right here! Is this a "spark" or a "shock"? Does she get zapped before or after the water's turned on? Back to you, Tom

If it's constant, it could be an electrical problem.

I'm thinking that it may be due to, for example, the material of the floor or the clothing worn prior to getting in the shower especially if it's carpeted. Change the carpeting or touch the wall first before touching the knob.

If the shock does not occur when touching the wall first, then I'd suspect the floor material.

Its called the peltier effect... Not to worry its not an electrical or flooring problem... What is happening is when the hot and cold pipes join it causes low voltage electrical current, this only happens in copper plumbing and more specifically non-grounded copper plumbing.

To fix the ploblem simply add a ground to the hot and cold water lines running into that room... a ground coming right off the pipe on the hot water heater is fine... or put some sort of insulator around any metal fixtures or buy new plastics ones...

This effect will feel much like a 9v battery to the tongue but will travel through your intire body... Also important to note is in order for this to happen you must somehow be grounding yourself... tile or concrete floor in the shower itself... the effect can also happen when one pipe is grounded but the other is not, when this is the case you should only be getting shocked when you touch both pipes or knobs at the same time... keep in mind you are in a room that sprays water every place so you may in fact be indirectly touching both contacts and not realise it.

Lastly, I'm not sure on this but I also believe that in order for the peltier effect to happened you must be using two different types of metal probably copper lines and brass fittings... I guess that's not important but I'm on a rant so...

Actually, what you are describing is the Seebeck effect, which has to do with electrical current. The Peltier effect results in a temperature differential. And having said that, I'm not convinced that this is some innocent demonstration of physics. Does it happen with cold water only on, or only with hot and cold both?