Wondering if that Mason duplex will actually cash flow, or just tie up your capital? You are not alone. Small multifamily in Ingham County can be a smart hold, but the numbers need to work on day one. In this guide, you will learn how to analyze a Mason duplex using cap rate, NOI, cash‑on‑cash return, and DSCR, plus how to plug in local costs like taxes, insurance, and utilities. Let’s dive in.

What cash flow analysis means

Cash flow analysis helps you decide what to offer and whether a duplex fits your goals. You estimate income, subtract realistic expenses, factor in financing, then measure returns. The goal is to protect your downside and buy with confidence.

Key metrics and formulas

• Gross Scheduled Rent (GSR): total annual rent if both units are rented at market rates.
• Effective Gross Income (EGI) = GSR − Vacancy Loss + Other Income.
• Net Operating Income (NOI) = EGI − Operating Expenses.
• Cap Rate = NOI ÷ Purchase Price. Shows income yield independent of financing.
• Cash‑on‑Cash (CoC) = Annual Cash Flow After Debt Service ÷ Cash Invested.
• Debt Service Coverage Ratio (DSCR) = NOI ÷ Annual Debt Service. Many lenders look for DSCR above roughly 1.2 to 1.25 on investment loans.
• Break‑even Ratio = (Operating Expenses + Debt Service + Vacancy Loss) ÷ GSR.

How to use cap rate and CoC together

• Use cap rate to compare what the property produces at today’s price, without a mortgage. It helps you judge value versus recent duplex sales in Mason and nearby Ingham County.
• Use cash‑on‑cash to measure your personal return after loan payments and cash invested. Your target can vary by strategy. Many buy‑and‑hold investors accept a lower CoC if they see solid upside, while cash flow investors often set a firm minimum.
• DSCR adds a lender view. If DSCR is thin, you may face tougher loan terms. If it is strong, you have more flexibility.

Gather Mason‑specific inputs

Local inputs make or break your underwriting. Start with real numbers, then tighten your assumptions during due diligence.

Rents and recent rental comps

Pull 3 to 5 comps for similar duplex units in Mason city limits or close‑in areas with a similar commute to Lansing. Match bedroom and bath count, square footage, and condition. Adjust for utilities included, parking, in‑unit laundry, and updates. Try to use leases or listings from the last 6 to 12 months.

Vacancy rate

Check recent data from the American Community Survey and local property managers for small‑multifamily vacancy. If you cannot source it, a starting range of 5 to 10 percent is common for similar Midwest markets near a college hub. Run sensitivity tests up to 10 to 15 percent to see your downside.

Property taxes in Michigan

In Ingham County, verify the parcel’s taxable value and current millage through the county or city assessor. Michigan tax math is straightforward once you have those two items.

• Tax formula: Taxable Value × Millage Rate ÷ 1,000.
• Be aware of the difference between taxable value and state equalized value. Confirm the current year bill and note any changes that may occur after a transfer.

Insurance for a duplex

Request quotes from agents who write landlord policies in Mason. Ask for replacement cost, liability limits, loss of rental income, and Ordinance and Law coverage. Premiums vary based on age, claims history, and coverage limits, so get two or three quotes before finalizing your numbers.

Utilities and municipal fees

Confirm who pays for water, sewer, trash, gas, and electric. Many smaller Michigan duplexes have the landlord paying water and sewer. Ask for 12 months of bills or the seller’s utility history to input realistic costs. If common area electric or heat exists, budget for it.

Local demand context

Consider proximity to Lansing and Michigan State University as broad demand drivers, along with commute patterns and local employers. Note neutral school district information, such as location within Mason Public Schools boundaries, as part of tenant demand research.

Property records, zoning, and environmental checks

Review the deed and any encumbrances through the Ingham County Register of Deeds. Confirm zoning and permitted uses with the City of Mason Building and Zoning Department. Check FEMA flood maps. For homes built before 1978, follow federal lead‑based paint disclosure rules and consider radon testing.

Build your operating budget

Your operating budget should reflect how the duplex will really function under your ownership, not just a best‑case scenario.

Expense categories to include

• Property taxes: use the latest bill or estimate with taxable value and millage.
• Insurance (landlord policy): update with quotes during due diligence.
• Utilities paid by owner: water, sewer, trash, common electric, and any shared gas.
• Repairs and maintenance: budget by unit or as a percent of EGI. A practical range is $500 to $1,500 per unit per year, or 5 to 10 percent of EGI depending on age and condition.
• Capital expenditures reserve: set aside for roof, HVAC, windows, and major items. Many investors reserve $250 to $1,000 per unit per year.
• Property management: 8 to 12 percent of collected rents for third‑party management. If self‑managing, you can lower the percentage but still value your time.
• Turnover and leasing: advertising, screening, rekeying, and cleaning. Budget a per‑turn cost and annualize based on expected turnover.
• Legal, accounting, and licenses: include rental licensing if required, bookkeeping, and attorney costs.
• Lawn care and snow removal: estimate per season or by contract.
• Miscellaneous: pest control, inspections, and HOA if applicable.

Typical expense ratios

Small duplexes often land in the 35 to 50 percent operating expense range as a share of EGI, but the real drivers are taxes, utilities, and management. Always defer to local bills and the seller’s history once you have them.

Step‑by‑step underwriting workflow

1. Gather property basics: unit mix, square footage, lot size, year built, assessed and taxable values, current rents and lease expirations, and payment history.
2. Pull 3 to 5 rental comps in Mason or nearby, then set market rent per unit and adjust for features.
3. Compute GSR from market rent or sustainable current rent.
4. Apply a vacancy assumption to get EGI, then add any other income like laundry or pet fees.
5. Build your operating budget with taxes, insurance, utilities, repairs, CapEx reserve, management, and other costs.
6. Calculate NOI = EGI − Operating Expenses.
7. Compute cap rate = NOI ÷ Purchase Price and compare to local duplex sales.
8. Add financing terms: down payment, rate, amortization, and loan fees to compute annual debt service.
9. Calculate annual cash flow after debt service and cash‑on‑cash return.
10. Run sensitivity tests for lower rents, higher vacancy, and rate shifts. Stress test to a tough but plausible case.
11. Inspect and verify: order an inspection, confirm taxes and insurance quotes, and price any deferred maintenance.
12. Decide your offer or pass based on targets for cap rate, CoC, and DSCR, along with risk.

Hypothetical Mason duplex example

The following numbers are for illustration only. Replace them with verified figures from your subject property.

• Property: 2‑unit duplex. Hypothetical purchase price: $180,000.
• Market rent: Unit A $900 per month, Unit B $850 per month. GSR = $21,000 per year.
• Vacancy: 7 percent. Vacancy loss = $1,470. Other income: laundry $300 per year.
• EGI = $21,000 − $1,470 + $300 = $19,830.
• Operating expenses (annual, hypothetical):
  • Property taxes: $2,400
  • Insurance: $900
  • Water/sewer and common electric: $1,200
  • Repairs and maintenance: $1,500
  • Property management at 8 percent: $1,586
  • CapEx reserve: $1,000
  • Miscellaneous: $500
  • Total operating expenses: $9,086
• NOI = $19,830 − $9,086 = $10,744.
• Cap rate = $10,744 ÷ $180,000 = 5.97 percent.
• Financing (hypothetical): 25 percent down ($45,000), loan amount $135,000, 6.5 percent interest, 30‑year amortization. Annual debt service ≈ $10,306.
• Annual cash flow after debt service = $10,744 − $10,306 = $438.
• Cash invested: $45,000 down payment + $4,000 closing costs and immediate repairs = $49,000.
• Cash‑on‑cash return = $438 ÷ $49,000 = 0.9 percent.

Interpretation: a cap rate around 6 percent with sub‑1 percent CoC is likely too tight for many investors unless there is a clear path to better rents or lower expenses.

Sensitivity checks to try

• 5 percent rent increase: modest rent growth can lift GSR and NOI and may double or triple CoC from a low base.
• 20 percent down instead of 25 percent: lowers cash invested but may raise annual debt service and reduce DSCR.
• Seller credit of $5,000 for repairs: reduces out‑of‑pocket cash and can improve CoC.
• Vacancy at 10 percent: shows whether the deal still supports the loan if leasing slows.

Standardized underwriting checklist

Use this checklist before you write an offer. Save documents, screenshots, and notes in one folder per property.

Property identification and legal

• Parcel ID, address, and legal description
• Deed and chain of title
• Seller disclosures and contact info
• Zoning classification and permitted uses
• Easements, encroachments, or liens

Financial and rent information

• Current rent roll with lease dates and security deposits
• Proof of rent collection, last 12 months
• Comparable rents, 3 to 5 items with details
• Historical operating statements, 12 to 24 months if available
• Current occupancy and lease types

Taxes and insurance

• Latest tax bill and taxable value
• Tax calculation worksheet using millage
• Two or more landlord insurance quotes with coverage notes
• Any assessments or special districts

Utilities and municipal fees

• 12 months of electric, gas, water, sewer, and trash bills
• Utility responsibility map by party
• Garbage removal contract or cost
• Any local rental licensing or inspection fees

Physical condition and maintenance

• Seller’s condition disclosures and current photos
• Full inspection report
• Lead‑based paint disclosure if built before 1978
• Age and service records for HVAC, roof, plumbing, and electrical
• Deferred maintenance list with contractor bids
• Pest or termite reports if available
• Environmental flags: floodplain check and radon test recommendation

Operating expense line items

• Property taxes, annual
• Insurance premium, annual
• Owner‑paid utilities, annual
• Management fee, percent or dollar amount
• Repairs and maintenance, annual
• CapEx reserve, annual
• Turnover and leasing costs, annualized
• Legal, accounting, licensing fees
• HOA fees if applicable

Financing and transaction costs

• Pre‑approval and lender terms: rate, points, amortization, DSCR requirements
• Estimated buyer closing costs
• Loan fees and any mortgage insurance
• Down payment and post‑closing liquid reserves

Underwriting calculations and scenarios

• GSR and vacancy assumption
• EGI and operating expenses
• NOI and cap rate
• Annual debt service and cash flow after debt service
• Cash‑on‑cash return and DSCR
• Sensitivity scenarios: rent down 5 to 10 percent, vacancy up to worst‑case
• Offer target and maximum price based on thresholds

Other due diligence

• Local crime and general neighborhood data from public sources
• Neutral school district information, such as boundaries and transportation
• Michigan landlord‑tenant rules and any local rental ordinances
• Permit history and any open permits
• Closing, inspection, and repair timeline
• Exit plan: hold period, target exit cap rate, rent growth expectation

Next steps

If you like the numbers, verify taxes, insurance, and utilities, then confirm condition with a strong inspection. Tighten your rent comps, update your budget, and re‑run cash‑on‑cash and DSCR before you commit. If you want a second set of eyes on underwriting or help sourcing duplex opportunities in Mason and the Greater Lansing area, connect with Josh Nelson for CPA‑level analysis and investor‑minded representation.

FAQs

What is the difference between cap rate and cash‑on‑cash on a duplex?

• Cap rate measures the property’s income yield before financing, while cash‑on‑cash measures your personal return after loan payments and cash invested. Use both.

What vacancy rate should I use when underwriting a Mason duplex?

• Start with locally sourced data when possible. If you do not have it yet, model 5 to 10 percent vacancy and stress test to 10 to 15 percent.

How do I estimate property taxes in Ingham County if I do not have the bill?

• Look up the parcel’s taxable value and current millage, then use Tax = Taxable Value × Millage ÷ 1,000. Confirm the latest year’s bill during due diligence.

How should I handle utilities in my cash flow model for a Mason duplex?

• Verify who pays each utility and request 12 months of bills. Include owner‑paid water, sewer, trash, and common area electric in operating expenses.

What DSCR do lenders typically want on a small multifamily in Michigan?

• Many lenders look for a DSCR above about 1.2 to 1.25. Stronger DSCR can lead to smoother financing and better terms.

What if the seller’s rent roll or income claims seem unreliable?

• Ask for leases and bank deposit history to verify collections. If uncertain, underwrite to more conservative rents or request a seller concession before moving forward.