On their website it states regarding rehabs that projects that will require to comply with IZ are:rehabilitation projects that are expanding an existing building by 50 percent or more and adding10 or more units.Just reading this, its unclear whether you have to have affordable units only if you expand a building by 50% or if you expand a building by 50% and in doing so add 10 or more units.

I would guesstimate anywhere from $50-75 per month per unit.

The property is in Maple Valley, so no the situation of all the new rules that are been imposed for Seattle now.

@Jason ChenYou should not rule out all of Citrus Heights.

I did read the EPA guideline which says that if your first test comes close to four there is a 50% chance that your yearly limit is under 4.0.  

Here are the key data points:Park info  Located in Alabama61 lots25 owner occupied homes18 park owned homes (14 currently rented; 4 currently being repaired and should be rented soon)18 vacant lotsAvg lot rent - $160 (unknown what the market rate is but it doesn't sound like there has been a rent increase in at least a year, maybe more)Avg POH rent - $400Expense ratio - seller claims 26% but I'm estimating 35% for the lots and 50% for the POH'sCity water - individually meteredSeptic - good condition (allegedly); a couple were pumped last year, none this year (no lagoon thank heavens)Seller claims gross income $130k, expenses $30k, and NOI $100kI calculated gross income of ~$135k, expenses of $60k (55% on POH and 35% on lot rentals), and NOI of $75kOther infoMom & pop seller, but park is listed with a brokerPark has been on the market for > 3 years (recent price reduction)Greater metro area stats look goodPopulation = 115kMedian home price = $105kUnemployment < 8%Household income > $40kHousing vacancy ~ 15%Closest Walmart is 7 miles awayFreeway is 1.5 miles awayNumbersMy valuation is coming out about $80k-$100k under the seller's asking priceWith conventional financing I'd be hoping for a purchase price of $500k, $100k down @ 6% over 20 years (not sure if this is plausible or not)Assuming that financing, I'm expecting net cash flow of $40k (after debt service)Upside potential is in raising rent and filling the 18 vacant lotsFollowing the same assumptions above, raising rent $50 (if the market supports it) would change NOI to ~$90k and net cash flow of just over $50kFilling the vacant lots could potentially increase gross rent up to somewhere between $150k-$200k, depending on what the appropriate occupancy rate is for the areaWithout verifying any of the above information (haven't offered anything yet so there's a lot of DD left to do), the deal seems to make sense. 

I've worked for a company that put in about 50 mid range boilers over the course of a few short years and spent about 50% of my time just trying to get them to limp along in the winter.

One of the rules of successful selling is that the price has to be transparent.

Potential Positive Changes:Add cheap home to empty spot, estimated $750 per month rentMonetize the Large Metal Shop Building through Rent, maybe $200-$400 per monthMonetize the RV spot, $50-$200 per month. 

I paid the $50 for the nationwide search and had a terrible experience.