How to estimate ARV without comps

[Ben Pasculano]

I am looking at a multi family property (2 units both 2 bed 1 bath) that is in need of a septic system replacement. I have talked with a septic company and gotten a range of what it could cost. I have been trying to do the math on the property to make a cash offer then pull out my money once the septic and some other smaller improvements are made. My issue is that I can not find any comps to get an ARV estimate. The town the property is in is much better than the surrounding towns. In the area there have been only 2 multi family properties sold in the last 18 months all in surrounding towns. What other ways are there to estimate an ARV?