Heloc on Owner occupied four unit

[Nnabuenyi Anigbogu]

Hello,

I am trying to get a Heloc on an owner occupied 4 unit building. I finally found a bank to do it and im in the underwriting stage. I am almost through but the last item i need to provide are the leases for all the rented units. My biggest unit is on a new lease so no problem there. However the other two are inherited month to month tenants. I didnt put them on a lease since i wanted the flexibility to replace one of them and the other one is in the process of trying to buy a place. However i jacked up their rents and they have been paying the new rents.

Since i haven't owned this long enough to put it on my taxes, what is the best way to prove the other two units are leased and use the income as part of qualifying? Do underwriters accept written letters from the tenants?

Thank you