20 Questions

Questions to Ask When Buying a Duplex

Critical questions to ask when buying a duplex about rental income, tenant history, property condition, expenses, zoning, and investment returns to make an informed purchase decision.

1

What is the current rental income for each unit, and is it market rate?

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Why this works

Assesses cash flow potential and whether rents can be increased.

2

Who are the current tenants, and what are the lease terms?

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Why this works

Reveals tenant quality, lease duration, and whether you'll inherit problem renters.

3

What is the tenant history—turnover rate, payment issues, evictions?

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Why this works

Surfaces red flags about tenant management challenges.

4

What major repairs or maintenance has been done in the last 5 years?

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Why this works

Identifies recent upgrades and deferred maintenance you'll inherit.

5

When were the roof, HVAC, plumbing, and electrical systems last updated?

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Why this works

Critical systems have expensive replacement timelines—know what's coming.

6

What are the average monthly and annual operating expenses?

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Why this works

Includes utilities, insurance, property taxes, HOA fees, maintenance, and management.

7

Are utilities separately metered, or does the owner pay some utilities?

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Why this works

Separate meters reduce landlord costs and tenant disputes.

8

What is included in the HOA or condo fees, if applicable?

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Why this works

Fees impact profitability—understand what's covered and if increases are planned.

9

Are there any pending special assessments or known upcoming expenses?

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Why this works

Surprises like roof replacements or sewer repairs can devastate cash flow.

10

What is the property's zoning, and can it remain a duplex?

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Why this works

Zoning changes could affect your ability to rent or sell as a duplex.

11

What is the property's rental history, vacancy rate, and average time to lease?

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Why this works

Reveals demand and how quickly you can fill vacancies.

12

Are there any code violations, liens, or legal issues with the property?

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Why this works

Legal and compliance issues can be costly to resolve.

13

What appliances, fixtures, and systems are included in the sale?

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Why this works

Clarifies what stays and what you'll need to replace or provide.

14

Has the property been inspected, and can I see the inspection report?

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Why this works

Reveals known issues and gives leverage for negotiations.

15

What property management company do you use, if any, and what do they charge?

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Why this works

Management costs impact profitability—get recommendations or plan for self-management.

16

What is the property tax assessment, and has it been appealed recently?

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Why this works

Taxes directly affect cash flow—know if reassessment will increase them.

17

What insurance coverage does the property currently have, and what does it cost?

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Why this works

Landlord insurance is typically higher than homeowner—budget accordingly.

18

Why is the seller selling, and how long has it been on the market?

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Why this works

Motivation and time on market reveal negotiating leverage.

19

What is the cap rate and cash-on-cash return based on current numbers?

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Why this works

Key investment metrics that show profitability and ROI.

20

Can I speak with current tenants before purchasing?

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Why this works

Tenants can reveal property issues and landlord relationships the seller won't disclose.

Evaluating a Duplex as an Investment

Expert tips and techniques for getting the most out of these questions.

Best Practices

Run the Numbers Conservatively

Budget for vacancies, repairs, and unexpected expenses—optimistic projections lead to negative cash flow.

Get a Professional Inspection

Never skip inspection—duplexes have twice the systems that can fail.

Review Actual Financial Records

Ask for tax returns, rent rolls, and expense statements—don't rely on verbal claims.

Key Financial Metrics to Calculate

Investment Calculations

1
Gross rental income (both units)
2
Net operating income (income minus all expenses)
3
Cap rate (NOI / purchase price)
4
Cash-on-cash return (annual cash flow / cash invested)
5
1% rule (monthly rent should be at least 1% of purchase price)
6
Debt service coverage ratio

Common Pitfalls

Underestimating Expenses

Factor in vacancies, repairs, management, insurance, and capital expenditures—not just mortgage and taxes.

Ignoring Tenant Quality

Problem tenants destroy cash flow and peace of mind—thoroughly vet current occupants.

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