When looking at homes in McHenry County you can view this website which will give you tax information:
When I have listed homes there, I always include the SSA in the tax amount and clearly state in the remarks section that there is an SSA and it is included in the tax bill. I agree with you, it should have been spelled out or mentioned to you before you looked at the house. One of the most important services I give to my clients is to educate them about the areas. There are many areas in McHenry County which imposed the SSA's because of all the building. Huntley, Cary & Wonder Lake are a few of them.
Because of the higher taxes, I have run across homes where the seller has or will pay off the SSA's before selling.
Good Luck in your home search!
Cary is wonderful. We loved living there so much and hated to leave. I do think it's the best place to live in McHenry County - it's got great people, great schools, and a great location. Don't let one realtor or one listing turn you off on the whole town. Good luck finding a house!
Good luck to you!