3 bedroom septic?

[ubrunnin]

I have recieved a permit for a 3 bedroom septic on my lot. ( North Carolina) My house plan only has 2 bedrooms, can I put a one bedroom efficiency apartment over my unattached garage, and tie it into my 3 bedroom septic?

[Mike Swearingen]

Septic systems are custom-designed for each specific property and planned number-of-bedrooms use in NC based on the soil type (1.5 people per bedroom...go figure).
The minimum size system permit is for a 3 bedroom home (which actually can adequately serve a 4 bedroom home), even if you're only planning a 1 or 2 bedroom home. Depending upon the soil type, they normally won't require additional drainfield lines until you go up to a 5 bedroom or higher.
You can't put two homes on the same system, but you should be able to tie-in your apartment, but they will have to modify your permit if they allow it.
Contact your local Health Department for permit and inspection requirements.
Good Luck!
Mike