What is a good cash flow rental?

The short answer

A good cash flow rental produces positive cash flow after realistic operating expenses, debt service, and reserves, and it still produces acceptable cash flow when one or two assumptions get worse.

That is intentionally more demanding than “the rent is higher than the mortgage.” The mortgage is only one cost. Vacancy, taxes, insurance, management, maintenance, capex, and turnover all compete for the same rent dollar.

There is no universal dollar amount that makes a rental good. A $100 monthly cash flow result can be strong in one market and dangerously thin in another. The number matters only in relation to the price, the risk, the financing, and the reserves behind it.

The benchmarks investors actually use

Monthly cash flow per unit

A common starting screen is $100 to $200 per unit per month after all operating expenses and debt service. Some investors target more, especially for older properties or lower-priced markets. Others accept less in expensive markets where appreciation is part of the thesis.

Treat the range as a convention, not a standard. A single-family rental with $100 of monthly cash flow has very little room for a vacancy or a repair. A 20-unit property with $100 per door has more diversification, but it also has more systems, common areas, and management complexity.

Cash-on-cash return

Cash-on-cash return divides annual pre-tax cash flow by the cash invested. Many leveraged investors look for a return in the high single digits or low double digits, but that is not a rule. The comparison should be with the return available on another property with similar risk, not with a number pulled from a social media post.

A high cash-on-cash return can come from a low down payment, optimistic rent, understated expenses, or a property with real operating risk. A lower return can be reasonable if the property is stable, well located, and financed conservatively.

DSCR

DSCR compares NOI with annual debt service. A DSCR of 1.00 means the property exactly covers its mortgage from operations. Below 1.00, the property needs outside cash to pay the loan.

A cushion above 1.00 is generally safer because NOI can fall. Lenders may require a certain DSCR for a particular loan product, but the requirement is not the same as a good investment threshold. A property can satisfy a lender and still be too thin for your risk tolerance.

The 1% rule and the 50% rule

Two old screening heuristics come up often:

• 1% rule: monthly rent should be at least 1% of the purchase price. A $250,000 property would need $2,500 monthly rent. In many markets, that is rare.
• 50% rule: operating expenses will consume roughly half of gross rent, leaving the other half for debt service and cash flow. It is a quick check, not an underwriting standard.

Both rules are useful for filtering a long list. Neither replaces a line-item cash flow model. Taxes, insurance, HOA dues, and capex can vary too much by property and market.

What a good cash flow number should include

Before you compare a property with a benchmark, make sure the cash flow number is complete. A good cash flow rental should account for:

• Realistic rent. Use rent comps and current lease terms, not a speculative post-renovation rent.
• Vacancy and credit loss. Include turnover, lease-up, and collection loss. Do not assume 100% occupancy.
• Property taxes. Use the reassessed amount after sale if local rules allow it, not only the seller’s current bill.
• Landlord insurance. Verify the actual quote. Replacement-cost insurance has become more expensive in many markets.
• HOA dues and special assessments. Read the HOA documents and reserve study if available.
• Property management. Include a market fee even if you plan to self-manage.
• Maintenance and repairs. Use a percentage of rent or a property-specific estimate.
• Capex reserve. Roofs, HVAC, water heaters, and exterior work are predictable over time even when the timing is not.
• Utilities and services. Count only what the owner pays.
• Debt service. Principal, interest, and mortgage insurance.
• Reserves. Cash set aside for vacancies, repairs, and capital events.

A cash flow estimate that omits management, maintenance, or capex is not a lower-cost property. It is an incomplete model.

Why positive cash flow is not enough

Consider a $300,000 rental with $2,600 monthly rent, 5% vacancy, $3,600 annual taxes, $1,800 annual insurance, and 18% combined management, maintenance, and capex. With 25% down and a 7% 30-year loan, the property produces about $55 per month and $661 per year in pre-tax cash flow. The cash-on-cash return is about 0.88%, and the DSCR is about 1.04.

That is positive cash flow. It is also a thin deal.

If vacancy rises from 5% to 10%, with the same rent and operating expenses, annual cash flow falls by $1,560. The result becomes roughly −$899 per year, or −$75 per month. A property that looked barely positive is now negative after one assumption change.

That is why the headline number is not the whole answer. The margin of safety is.

A practical scorecard

Use a simple scorecard before you fall in love with a deal:

Question	What good looks like	Why it matters
Does it cash flow after all expenses?	Positive after management, maintenance, capex, and debt service	A positive number before reserves is not spendable cash
Is there a cushion?	A stress case with higher vacancy and expenses still works, or the shortfall is manageable	One surprise should not break the plan
Does NOI cover debt service?	DSCR above 1.00 with room to spare	Cash flow depends on the loan as well as the property
Does the return justify the risk?	Cash-on-cash return is competitive with alternatives of similar risk	A low return for high risk is not a good deal
Is the property in a durable market?	Supported by employment, population, and rent demand	Cash flow can disappear if the tenant pool shrinks
Are the expenses complete?	Taxes, insurance, HOA, management, maintenance, capex, and reserves are all included	The most common error is an optimistic expense list
Is the financing sustainable?	Payment is manageable if rates or insurance change	A deal that only works at the lowest available payment is fragile

The scorecard is not a scoring system. It is a checklist for the questions that a single cash flow number can hide.

Stress-test the deal

A base case is necessary. A stress case is what tells you whether the base case is robust.

Try these changes one at a time, then together:

1. Increase vacancy by 5 percentage points.
2. Reduce rent by 5% to 10%.
3. Increase property taxes by 10% to 20%.
4. Increase insurance by 10% to 20%.
5. Add a management fee if you planned to self-manage.
6. Increase the interest rate by 1 percentage point.
7. Add a capital expense such as a roof or HVAC replacement.
8. Hold the property vacant for one to two months between tenants.

The question is not whether the property survives every possible disaster. It is whether the cash flow you are relying on has a reasonable margin for normal operating variance.

If the deal only works when everything goes right, it is not a good cash flow rental. It is a bet on a perfect outcome.

Cash flow versus total return

Cash flow is one part of a rental return. A complete view also considers:

• Principal paydown. The tenant’s rent retires debt and builds equity.
• Appreciation. The property may increase in value, but it is not guaranteed and is not spendable until sale or refinance.
• Tax treatment. Depreciation and deductible expenses can affect after-tax returns, but they do not pay the mortgage.
• Sale or refinance proceeds. Transaction costs, taxes, and loan terms can change the outcome.

Some investors accept low or negative cash flow because they expect appreciation or principal paydown to compensate. That can be a legitimate strategy, but it is not the same as buying a cash-flowing rental. It requires reserves to cover the shortfall and a clear thesis for the exit.

How to evaluate a cash flow rental

1. Estimate rent from comps. Use current leases and recent comparable rentals, not the listing’s pro forma.
2. Verify the expenses. Get tax bills, insurance quotes, HOA documents, and a property inspection.
3. Build NOI. Subtract vacancy and operating expenses from gross scheduled income.
4. Add the financing. Calculate the loan payment, including PMI if applicable.
5. Calculate cash flow, cash-on-cash, and DSCR. Use the cash invested, not the purchase price, as the denominator for cash-on-cash.
6. Stress the assumptions. Change vacancy, rent, taxes, insurance, and the interest rate.
7. Check the reserves. Make sure you have cash outside the deal for vacancies and capital events.
8. Compare on a consistent basis. Use the same expense and vacancy assumptions for every property.

The rental cash flow calculator runs these steps and shows the break-even rent, cash-on-cash return, DSCR, sensitivity table, and five-year projection. If you want the property-level yield before financing, start with the cap rate calculator.

The bottom line

A good cash flow rental is not defined by a single monthly number. It is a property that produces positive cash flow after realistic expenses, has a cushion for normal surprises, covers its debt service with room to spare, and offers a return that compensates you for the risk.

Use benchmarks as a first filter, then underwrite the specific deal. The best cash flow number is the one that still looks reasonable after you stress it.