My mother in law has been taking water pills for quite a while. I don't know what she is taking them for I just found this out. They are running tests on her kidneys now because they think the water pills have damaged them and they said she should never have been on them for so long. Does anyone know what water pills are for and how they damage the kidneys?

Water pills are diuretics, so they stimulate kidneys to get rid of water + salt. You have to find out why she was given these. Water pills are also helping in regulating blood pressure, since the less water is in your blood the easier heart has to pump.
I don't know about side effects of water pills or if they can damage the kidneys, but who knows. They are usually given if you have water retention, problems with kidneys or if your blood pressure. I read that they are the most comonly overprescribed medication, so perhaps they are used for anything and everything.

i have a kidney transplant and was prescribed water pills, i dont hink their any side affects unless the whole prescript is taken