The most common rental property mistake isn’t overpaying. It’s underestimating expenses. On paper, rent minus the mortgage payment looks like profit. In practice, vacancies, repairs, replacements, management and turnover take a big bite, often around half of the rent before the mortgage is paid.
This guide lists the costs new investors miss, gives typical budgeting ranges, and shows how a “$640 a month profit” can turn into a loss.
The expenses to budget for
| Expense | Typical budget | Notes |
|---|---|---|
| Vacancy | 5%–8% of rent | One empty month a year is 8.3% |
| Repairs and maintenance | 5%–10% of rent | Higher for older homes |
| Capital expenditures (CapEx) | 5%–10% of rent | Roof, HVAC, water heater, appliances, flooring |
| Property management | 8%–12% of collected rent | Plus leasing and renewal fees |
| Property taxes | Your local tax bill | May rise when the property is reassessed after a sale |
| Insurance | A landlord policy | Usually costs more than a homeowners policy |
| Utilities you pay | Varies | Water, sewer and trash are often the owner’s cost |
| HOA dues | Varies | Also count in lenders’ DSCR calculations |
| Lawn, snow and pest control | Varies | Often the owner’s job for single-family rentals |
| Turnover | Varies | Cleaning, paint, repairs and lost rent each time a tenant leaves |
| Legal and admin | Varies | Eviction costs, rental licenses, accounting and software |
These are rules of thumb, not guarantees. Use your own quotes and local knowledge when you have them.
Vacancy
Even good properties sit empty between tenants. Budget at least a few weeks a year, and more in slow markets or for seasonal rentals. While a unit is empty, you still pay utilities, lawn care and the mortgage.
Repairs vs. capital expenditures
Repairs are the small, frequent fixes: a leaking faucet or a broken dishwasher. Capital expenditures are the big, infrequent replacements: a roof, a furnace or a water heater. CapEx is the cost most often left out, because it doesn’t show up every month. Setting money aside monthly keeps a $10,000 roof from wiping out several years of cash flow.
A simple way to size your CapEx reserve is to list each big component, estimate its replacement cost and remaining life, and divide. A $12,000 roof with 10 years of life left works out to $100 a month.
Management
Budget for management even if you manage the property yourself. Your time has value, and you may hire a manager later. Managers typically charge a percentage of collected rent, plus a leasing fee (often half to a full month’s rent) when they place a new tenant.
Taxes and insurance
Property taxes are often reassessed after a sale, so the seller’s tax bill can understate yours. A landlord policy covers the building and your liability, but not your tenants’ belongings, so ask tenants to carry renters insurance.
The 50% rule
A quick screening rule says operating expenses, meaning everything except the mortgage payment, average about 50% of rent over time. It’s crude, and new or low-maintenance properties can do better. But it’s a useful reality check when a listing claims expenses of 25%.
A worked example: the $640 “profit”
A single-family rental brings in $2,000 a month. The mortgage payment is $1,000 for principal and interest, property taxes are $250 and insurance is $110.
The naive math: $2,000 − $1,360 = $640 a month of profit.
A realistic budget:
| Line | Monthly |
|---|---|
| Rent | $2,000 |
| Vacancy (8%) | −$160 |
| Repairs (8%) | −$160 |
| CapEx reserve (7%) | −$140 |
| Management (10%) | −$200 |
| Property taxes | −$250 |
| Insurance | −$110 |
| Water, sewer and trash | −$60 |
| Lawn care | −$40 |
| Net operating income (NOI) | $880 |
| Mortgage (principal and interest) | −$1,000 |
| Cash flow | −$120 |
Operating expenses total $1,120, or 56% of rent, close to the 50% rule. The “profit” was really a $120 monthly loss once realistic costs were counted.
That doesn’t automatically make it a bad investment. Paying down the loan, appreciation and tax benefits add to your return. But you should know the true cash flow before you buy, and keep reserves to cover it.
How to protect your cash flow
- Get real numbers. Ask the seller for utility bills and repair records, and get insurance and tax estimates before you make an offer.
- Inspect the big-ticket items. A roof, HVAC system or sewer line near the end of its life belongs in your offer price.
- Keep reserves. Many investors keep three to six months of expenses per property, and DSCR lenders often require reserves too.
- Screen tenants carefully. Turnover and evictions are among the most expensive events a landlord faces.
- Review every year. Compare actual costs with your budget, then adjust rents and reserves.
Taxes: many expenses are deductible
Most of these costs, including mortgage interest, property taxes, insurance, repairs, management and utilities, are deductible against rental income. You can also depreciate the building (not the land) over 27.5 years for residential rental property. Improvements are generally capitalized and depreciated rather than deducted at once. IRS Publication 527 explains the rules.
Run your own numbers in the rental property calculator. It includes vacancy, maintenance, CapEx and management, and shows your cap rate, cash-on-cash return and DSCR. For deals you’ll renovate and refinance, use the BRRRR calculator. To see how the return measures differ, read cap rate vs. cash-on-cash return.
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