On Friday, May 8, 2015 at 8:00:34 PM UTC+1, gareth wrote:

What's the danger here, when tap water from a soft water area
is so much more potable?

Soft water is NOT the same as softened water.

Soft water contains little/no dissolved hardness salts. The hardness salts are usually calcium bicarbonate and carbonates which are dissolved chalk or limestone from wells.

Softened water is treated hard water; the calcium carbonate & bicarbonate is changed into sodium carbonate (washing soda) and bicarbonate (baking soda), which are much more soluble.

There are those who say it's safe to drink softened water but they're usually installers who want to dodge the grief of amending the pipes to the kitchen tap.

How much washing soda would you be happy to ingest?

not

Also, can softened water be used on the garden and to fill the fish pond?