Trying to assess value of rental park


I am trying to put a value on a park with 1 house, 20 spaces of which 18 are rentals and 1 is vacant.

I have all the financials, but they include all rental income and I have been advised to ignore rentals and just look at lot rent.

How should I convert?

Rent income: $69000

Advertising $400

Insurance $1800

Parts and Supplies $5300

Repairs $5300

Taxes $1900

Gas and Electric $2400

Water and Sewer $11600

Mngmnt cost $2400

NOI $38K

My plan is to sell all the homes to the renters and submeter the water.

Avg lot rent in the area is $160 monthly without water or $175 with water. The 1 lot rented is at $160 and includes water.

Over the last year it averaged 76% full.

The house rents for $450 and I can value it apart from the park at $23K

To put a value on the park do I assume all MH rented at market rates? Then I need to somehow decrease repairs and parts and supplies as well to get a pro-forma NOI? If I do not decrease Parts and Repairs the NOI will be negative.