What price is an average water bill?

I am billed every 4 months, and I want to know what the average utility bill for a small family is. I am in Fairfax County VA, but anyone who helps me with this I would appreciate. My home has two adults and one child, so anyone close to our size for a household, if you could give me a ball park of what I should be paying for this particular utility. I have a suspicion that I am paying too much.. Thanks for the help!