water

That depends on the source of the water.

The term "Hard" water (not to be confused with heavy water) contains calcium and magnesium. Water softeners are used to remove these minerals. Usually well water in most states needs to be treated to remove these minerals, but some wells have very low mineral amounts.

Purified water removes these and distilled water even more so.

If the local rock is chalk, limestone or anyother variant of calcium carbonate .... the answer is yes.

Yes The level of which depend upon the geology of the area it comes from and how its collected. Areas high in limestone would have high levels of calcium in the well water. Water collected from the rain falling in the same area would have trace amounts. Calcium is one the dissolved mineral found in the water.

4 out of 4 of the first responders say......YES. Though it can be unnaturally found in water too.

You can fortify and flavor your bottled water by crushing and adding products such as Tums with calcium.

Absolutely. That's one of the things a water softner removes from water to make it "soft". It replaces the calcium ion's with sodium ions. The sodium components won't precipitate from the water, and eliminates the formation of a ring around the tub!

I hate those softeners. I always feel like I still need to rinse.

More importantly, try not to drink to much of it. Softened water can have too much sodium in it for some people (especially those with hypertension). In that case, you're definitely better off washing with it, and not drinking it. On the otherhand, in Bangladesh, they'd probably love to just have any kind of water to drink that did not contain unusually high levels of arsenic.

Calcium is found to varying extents in all surface and spring waters, including seawater.

Calcium is added to RO permeate and evaporator distillate produced from water-makers on ships so as to add some taste and reduce the prospect of corrosion in the downstream pipework.

Yes for hard, no for soft.