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Corrosion of stainless steel piping and utensils in new house

We have moved to a new house that was built last year. all the sanitary fittings are of stainless steel (I checked it with a magnet, not attracting). However, with exposure to underground water it is rusting. Even some utensils show some rust. I used to think that SS does not rust. Any idea why? By the way, the water is very hard and we have to use a Reverse Osmosis unit before drinking/cooking. also, corrosion starts within a month of exposure

Amit Talukdar
- New Delhi, India
August 15, 2008

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As a gunsmith I have lost track of how many times I have heard "stainless can't rust" while my customer is standing there holding a firearm with rust spots.

There are different grades of stainless, lower grades will rust, people automatically hear "stainless" and they think "rust proof" when they should be thinking "rust resistant"

Are you sure it's rust and not some sort of mineral deposits caused by your hard water?

Also, the magnet test is not a definite indicator of whether a substance is stainless or not, there are types of stainless that are magnetic (I forgot which type) and others that are not magnetic.

Brian F Bonser
- Stuart, Florida, USA
August 19, 2008