I assume that the HOA controls the water in the complex and that part of your dues takes care of the water? Not paying the dues is not a reason that they would elect to shut off the water or any other utility for that matter. If you were paying the utility directly they would not shut off the water. It's likely this HOA has used this tactic before to force people into paying the bills. Hardship is hardship and they should not be doing that. It's likely that they're telling the water company that your unit/home is vacant to get them to shut it off. Because I don't believe they would do it if someone is living there.
Running water is essential in life and they is why they will not shut it off.
I would suggest you call the water company directly and ask them why it was shut off. Just assume you have no idea and are just wanting to make sure there is not a problem and advise them your family has no running water. See if you can find out what happened. The HOA cannot hold the water over your head to force you to pay them everything. Bad tactic.