Question:
One of the old timers in our area who happens to own a pipe and sulvert supply business and some awesome dirt working equipment asked us about our place design while he was digging a big hole for us. When we showed him where we were planning on putting our catch water cistern he suggested that we make it from culvert rather than cement or buying a prefab tank

Any opinions?

Answer: Since many of the prefab tanks we've been looking at are galvanized I'm assuming galvanized is OK for untreated water. This isn't a cistern we would use for drinking water except under extreme circumstances. If we get that dry the water would have to be removed and filtered before being "bleached." We have considered using a similar cistern for extra drinking water storage, though.

It was my pleasure to attempt to help out, and its good to hear that you have a self sustaining source of fresh drinking water other than your planned cistern.

I did do some research today on this issue, and I found some interesting things.

It was my mistake that Chlorine reacts with the Zinc Galvanized coatings < so far>, as I have found no backup information to support my concern. However I did locate the passage that I had read concerning Zinc in water tanks and the reactive chemical was Copper Sulfate as well a high and low pH levels.

"Galvanized Steel has been used to water livestock and hold potable water for years however, at a high and low pH level, zinc may be given off to the water, and could pose a problem in some situations"