Teach me about Flood Insurance

Today my wife and I attended an open house and much to my suprise it is a place that I really like. It is a walkout basement. The raised deck out back over looks a nice wooded area and a small creek.
That led me to wonder about flood plain.
The realtors assistant who was hosting really knew nothing about the property and or said very little when I asked. When I got home I pulled the property up on the county auditors website and I see that half the house sits clearly in "the red zone" of being a flood risk.

So, how does this work?
Any idea what this insurance might cost on a nearly $200k house?
If I am correct, the lender will require this insurance, right? It would probably be foolish to not have it.
This is in North Ohio if that makes a differnce.

Yup, lenders will require flood insurance if it's in a flood plain. I'm having to get that done for one of my dad's estate's properties soon. It's separate from a regular homeowners' policy, it's through a federally backed corporation. No idea what it would cost, though.

lenders require it. my parents are in a flood plain, there is a river 100' from the front door of the house. through state farm theirs adds a little over $500 per year and their house is insured ~$240k

Which flood plain? There are 30yr, 100yr and 200yr floods. If you want to know the consequences of being in a flood zone, go read about the Nashville flood of 2010. I am surprised that the realtors were not being more proactive about the presence of the flood zone.
It can radically affect the value and marketability of your investment. I have a lawsuit right now in development where a interstate gas pipeline easement takes up the entire backyard and no one told the purchasers. Would you want that pipeline in your backyard?

My current Flood ins is 310.00 a year through AAA on a house I paid 265 for in FL. Be aware that "flood" insurance only covers rising water, not falling water. So, river, canal, lake etc. gots too full and comes in your door, you're covered. Roof leaks, pipe breaks, toilet overflows, no coverage.

I'd find out if there's been any floods since the house was built and have a mold test done if there was before buying the home. I've had lots of experience with floods/mold etc. in homes I've lived in.

Last residence before my current one was in CT. The water got as high as the floor joists of the deck during the worst floods. Thats over 6' of water if you were standing in the yard! (only about 3-4' in pic)