I suggest you not to bother. May need to get a spare pump and perhaps water level alarm system.
Cost in my conversion:
1. connection permit (different from city to city and lot to lot in the same city. My lot is one acre)
2. within house drainage pipe slope adjustment plumbing expense (I got hold of one plumber that agreed to use same copper pipes. Saved me quite a few k$. Septic tank is in backyard but city sewage connection in front yard close to street
3. digging and laying pipes outside of house
4. sprinkler repair (old sprinkler pipes were cut in construction and filling out septic tank)
5. lawn repair and landscaping (to fix soil settling)
My # is not a good reference to you. I think around $25-30k including $11k on permit.
