We have some hunting property that our family has used since the 40's.  The only building it has is an old shack and an outhouse.  This has served it's purpose well but now my brother and I are planning on building an actual house or cabin with running water, toilets, showers, kitchen sink, washing machine, etc. when we bring the wife and kids.

However when we went to the county to get a permit, they said we would need a full septic system.  After calling a few contractors in the area, we found out this would add at least another $4,000 to our costs of this project. 

Since we are only going to be using this property on weekends I don't see why we should have to spend this kind of money on something that is not going to be used year round.  I say they are going too far.  Why are they doing this? Dan F

Every home produces wastewater...even a weekend cabin. That wastewater contains parasites and viruses (from human waste), nutrients (manure...again from human waste) and chemicals from cleaning compounds. If you just dumped this wastewater into a ditch, like they did years ago, any people that came in contact with these contaminates could get sick and die, like they did years ago. Animals that come in contact with this brew, like, dogs, cats and mosquitoes, can acquire these health hazards and pass them a long to humans. 

FYI: Mosquitoes have killed more people by spreading disease than all the wars put together.  

The fact is, in the year 1900, the average life span of an American was 49 years old. You see in those days people didn’t give a whole lot of thought to sewage treatment.  Often raw sewage was just piped to a ditch, lake or river.  Needless to say, waterborne disease was rampant.  A disease causing parasite would often get into a local water supply and people would start getting sick.  And because there were no  antibiotics available, many of these people would die. Nasty deal wasn’t it.

There has been a lot of damage from un-treated sewage entering our lakes, rivers, oceans and drinking water supply's...this is why most areas of the country are requiring you put in a proper system to deal with your wastewater. 

As far as your concerns about the cost: 

I would say this property was paid off a long time ago by your grandparents, which means all it is costing you now is a share of the property taxes every year.  In other words, you ain't exactly paying top dollar to begin with. You scored a pretty good deal.  
Owning a home is a responsibility and making sure you do not pollute the environment or water supplies is part of that responsibility.  If you do not want that responsibility, then sell the property and stay in the city.  But if you are going to make poop, you gots to take care of it.  
You are whining about adding 4 grand to a property that you probably got for free and will be worth a lot of money to you in the future.  Put it in perspective and it doesn't look too bad.  
Jim