Where to find accurate Data for MA ADUs

Question

Hi everyone,

I've recently started looking into strategies for converting auxiliary space (e.g. living rooms, garages, etc) into ADUs in the MA markets (I'm located in the Greater Boston Area, but I'm open to investing in other parts of the state). It looks like as of February 2025, ADUs are now allowed by right. However, since this development is so recent, I'm wondering where I can find accurate numbers to calculate things like:

-expenses (how much it costs to build an ADU based on type; e.g. living room conversion, garage conversion, other, etc)

-financing

-comps for how much ADUs can add to the value of the home

-comps for how much ADUs can rent for

-demographics for likely ADU renters (for example, there may be fewer international students coming to the US YoY, and layoffs/hiring freezes hitting the Biotech and tech sectors may result in fewer young professionals in the area; if I understand correctly, college students and young professionals are the primary tenant demographics for ADUs)

Thanks,

Hanbo

Lien Vuong · Answer

This collective data doesnt exist altogether unfortunately. It's a manual search and something you have to narrow down to at least the town/area you want and then do the deep drive. While ADUs are permitted by right, there's still limitations on where you can build it and the municipality still has the final say so we cannot say broadly that all homes are ADUable. For example, Revere MA does not allow for ADUs if the home already has a multi family unit, its only permissible in a single family home.

Hanbo Lin · Answer

Could one use CA or other HCOL areas as a comp if the data doesn't exist yet? For example, could one say that the Greater Boston Area is roughly similar to the Bay area in terms of composition (universities, tech employers, demographics, etc) and use that as a rough initial benchmark for the numbers?

How would one do the manual search and deep dive, and what types of people should I even be talking to in order to find out more?