OWTS * On-Site Wastewater Treatment System Permits

What the System Is
A septic system is a method of disposing and treating household wastewater in areas where public sewers are not available.

The standard type of septic system involves a septic tank, to hold wastewater from toilets and drainpipes until solids settle out in the tank, and a system of pipes that distribute the remaining liquid waste underground over a large area --the leach field--where the wastewater "percolates" through the soil, which helps to clean the water. 
On-Site Wastewater Treatment System Regulations

The goal is to make sure that this filtration though the soil is sufficient to clean the wastewater before it reaches drinking water well sources or surface waters.

Additional Resources
Gunnison County refers to these systems as On-Site Wastewater Treatment Systems (OWTS) Additional information is available from:
Permit & Cost
Colorado and county regulations require that a permit be issued by the Environmental Health Office before a property owner constructs or repairs a septic system.

The cost for a permit to construct a new system or repair an old one are listed in 
OWTS- On-Site Wastewater Treatment System Permit Application
Legal Lot
Also check the records of your property to ensure that you have a legal lot.