Is it part of your income plan to tap it?
I wouldn't count it as part of the 4% WR, because it's already generating an income (the rents), so double counting the equity doesn't help you.
I would do your personal gross expenses minus SS/pension/rents to get your net expenses, and then 4% rule what's needed for that (multiply by 25) and only count your investment portfolio that you're planning on tapping for that 4% withdrawal.
Otherwise you could count the equity at 4%, under the assumption you're going to sell and invest the 4%, but then not count the rent received as reducing your expenses.