you should be able to tell if your water is hard or not quite easily:

1)if you take a shower and it dries your skin->hard
2)if its well water without a purifier or softener->hard
3)try boiling the water in a pan, see whats left over when there no water left. (dont use a really nice pan)

what i do to solve this hard/soft water dillema is just use distilled water. you can get it really cheap if you buy it like 10 gallons at a time in big jugs. this way your guarenteed soft water.