Places like Home Depot sell water test kits you can do yourself at home. They are cool...kindof like little chemistry sets (viles and such). They work great! We used them when we first bought our house to find out what our water is like.
They not only tell you if you have hard water, but also tell you which natural and chemical balances are predominent (iron, chlorine etc).
I think those kits are $20 (maybe a little less...cant remember).
i am going to see if our WM or hardware store has one of those i believe we have hard water based on the toilet and shower/sinks.