Going to be building in a development where they use septic systems.  How much is it going to cost me?  Butch

The costs of a septic system will vary around the country according to local labor and material rates.

In the mid-west where materials and labor rates are reasonably priced, a standard, gravity-fed tank and trench system will run $3,000 to $5,000. The cost to pump/inspect the tank (every 1 to 3 years) will run $75 to $150 per pumping.

Engineered systems, like mounds, sand/peat filters, aerobic systems and constructed wetlands will run $6,000 to $10,000. Occasionally they can run in the $15,000 dollar range. Cost to operate and maintain will generally run about $8 to $15 per month.

A cluster system, where each home has their own septic tank but empty into a community drainfield will generally cost $5,000 to $8,000 for the initial install and $5 to $10 per month to operate and maintain.

Any type of septic system, if it is used properly, has the potential to last 20, 30, 40 years or more. Some systems will need pumps replaced periodically and treatment media rejuvenated.

Of course the proper operation and management of any system is dependant on educating the people that use those systems how to properly use those systems...something that has been missing from the equation from day one.

Conversely, a sewage treatment facility will usually cost $12,000 to $30,000 to get hooked-up and $350 to $1,000 per year. 

Now when you get to certain parts of the country, because of higher local costs, these figures can increase by 50% to 100%.  Jim

When you buy property and are going to put in a septic system, there are safeguards that are supposed to protect you.  The way the process is supposed to work is, you, as the property owner, hire a septic designer to assess the site and design a system that will meet the needs of the home and will work with the existing site/soil conditions. They then present this plan to the local agency in charge of septic systems, usually the health or zoning office. They approve or disapprove the plan. Then a septic installer installs the system according to that plan. Then the building inspector comes to the site and inspects the system to make sure the system was installed properly (according to the plan). 

This is the way it is supposed to work...but it doesn’t always go according to the rules. The skill requirements of designers, installers and inspectors varies greatly from state to state. In some cases these people are woefully under trained and because of this lack of standards, some of the systems going in are failures waiting to happen. This is why you as the homeowner must take an active role in this process.