Calculate ADU's price per sqft

[Chakri Dew]

Hi BP'ers,

I am new to the multi-unit world.

How do you calculate the ADU's price per sqft if it is not in the county records? I am assessing a duplex property and an ADU (ground floor unit) rented as commercial office space some years ago. (Property is eligible for duplex and hybrid according to the county zoning map)

The price per square foot is on par with the rest of the regular units.

Two units: 600x2 = 1200 sqft

ADU: 1200 sqft.

Listed price: 984,000 [(1200+1200)sqftx$410]

According to county records, it has 1200 sqft. I am under the impression, ADU sqft is not calculated as part of the regular footage price. (correct me if I am wrong.) How should I run the numbers with ADU in the price factor?

Additional questions,

- Do I face any legal consequences if I rent an ADU, not in county records?

- How does the property insurance work for it? Do I need to take hybrid insurance or unit-by-unit?

- How do I add the additional unit (ADU) to the county records? Is it a nuisance to add an existing build unit to county records? Building codes etc come to the play and redo some work? The city is ADU-friendly and encourages them.

- Property year is not listed in the county records despite property taxes are paid regularly. Is it straightforward to add to the records with the city clerk?

Thank you. 

Chakri