Most apartment buildings in the United States are required by their zoning code to provide a minimum number of parking spaces, usually expressed as a ratio: one space per unit, one and a half, two. The requirement is rarely controversial when it is adopted. Residents own cars, the street should not fill up, and the developer is the one paying. But the developer is not the one paying. The tenants are, through rent, for as long as the building stands. This article works out how much.
The answer depends almost entirely on one question: where does the parking go? A space on an asphalt lot costs a few thousand dollars. The same space inside a concrete structure costs several times that, and below ground it costs several times more again. A parking ratio that is harmless on a large suburban site becomes one of the largest single costs in the building once the site is small enough that the cars have to be stacked.
Parking requirement
+$3.24M
+$183/month
What a parking space costs to build
A parking space is not just the painted rectangle. It is the rectangle plus its share of the drive aisle, ramps, entries, lighting, drainage, ventilation, fire protection and structure, which is why a space in a garage occupies roughly 300 to 350 square feet of built area. We do not have a verified public source for construction cost per space in this article, so the figures below are assumptions we chose to be plausible, and we present them as ranges rather than point estimates. An editor should replace them with cited figures before publication; the arithmetic that follows does not change.
Assumed construction cost per parking space by type (illustrative ranges)
See the numbers
| Category ($ per space) | Low end of assumed range | High end of assumed range |
|---|---|---|
| Surface lot | $4,000 | $10,000 |
| Tuck-under / podium | $15,000 | $30,000 |
| Above-ground structure | $20,000 | $40,000 |
| Underground | $35,000 | $75,000 |
For the calculations in this article we assume a single figure from each range: $6,000 per surface space, $22,000 per tuck-under or podium space, $27,000 per space in an above-ground structure and $50,000 per underground space. The important thing is not the exact figures but their ratios. A structured space costs roughly four to five times a surface space; an underground space costs roughly eight times.
From construction cost to rent
Parking is a capital cost, so it enters rent the way every capital cost does: the money that built it was borrowed or invested, and it must be serviced every month. We use the same method as every rent-impact figure on Housing Unpacked, described in full on our Methodology page and adjustable in the Rent Impact tool.
Annual debt service = Cost × 0.65 × 0.075848 (65% loan-to-cost, 6.5%, 30-year amortization)
Annual equity return = Cost × 0.35 × 0.08 (35% equity at an 8% cash yield)
Blended charge = Cost × 0.077301 per year
Rent impact = Cost × 0.077301 ÷ 0.95 ÷ units ÷ 12The 0.95 grosses the figure up for a 5 percent vacancy allowance. On 120 units, every $1 million of capital adds $56.51 to monthly rent per unit.
Apply that to one space per unit on a 120-unit building and the type of parking makes the difference between a rounding error and a car payment.
| Parking type | Assumed cost per space | Capital for 120 spaces | Rent impact per unit per month |
|---|---|---|---|
| Surface lot | $6,000 | $720,000 | $40.68 |
| Tuck-under / podium | $22,000 | $2,640,000 | $149.18 |
| Above-ground structure | $27,000 | $3,240,000 | $183.08 |
| Underground | $50,000 | $6,000,000 | $339.04 |
The surface figure, $41 a month, is why parking minimums attract little attention in places where land is cheap. The structured figure, $183, is why they attract a great deal of it in places where land is not. And the underground figure, $339 a month for one space per unit, is a large part of why apartments on expensive urban sites are so much more expensive to build than the buildings themselves would suggest.
What the requirement itself costs
The table above answers what parking costs. It does not answer what the requirement costs, which is a different and harder question. A developer on a site with room for surface parking would probably build some parking without being told to, because tenants in most markets expect it and will pay for it. The cost of the mandate is the difference between what is required and what would have been built anyway. Nobody can observe the second number directly, so we model a case.
Parking structure: 120 spaces (one per unit) at $27,000 per space
- $3.2M
- 120
- $27,000
- $263.6K
Estimated rent impact
+$183/month per unit
Illustrative. Assumes the site cannot accommodate the required spaces at grade, so every required space is built in an above-ground structure. Change the cost, unit count or financing terms to see the effect.
Change the variables
See the assumptions
- 65% of the cost is financed with debt (loan-to-cost)
- 6.5% interest rate, amortized over 30 years
- 8% annual cash-on-cash return required on the 35% equity share
- 5% vacancy and collection loss
- Costs are spread across every unit and expressed per month
| Debt | $2,106,000 |
|---|---|
| Equity | $1,134,000 |
| Annual debt service | $159,736 |
| Annual return on equity | $90,720 |
| Required net operating income | $250,456 |
| Required revenue (after vacancy) | $263,638 |
| Per unit, per year | $2,197 |
| Per unit, per month | $183 |
Now consider a constrained infill site. We assume the developer, left to choose, would provide one surface space per unit, 120 spaces, because that is what the site can fit at grade and what the market expects. We assume the zoning code instead requires 1.5 spaces per unit, 180 spaces, and that the only way to fit 180 on the site is to put all of them in a structure. The requirement does two things at once: it adds 60 spaces, and it forces all 180 into the expensive format.
Cost of a 1.5-space requirement on a constrained site
Difference+$233.94 / month
Rent impact per unit under the modeled financing assumptions. The $4,140,000 difference in capital is the cost of the requirement, not of parking as such.
The two effects can be separated. The 60 additional spaces alone, at $27,000 each, are $1,620,000 of capital and $91.54 a month. The remaining $142 a month is the cost of moving the first 120 spaces from asphalt into concrete. This is the part of the story that parking debates usually miss: on a tight site, the marginal space is not the only expensive one. The requirement can change the construction type for every space, and sometimes for the building above them.
The operating cost of parking
Structures also cost money to run: lighting, sweeping, gates, ventilation, periodic sealing and eventual restoration of the deck. We have not included these in the figures above. If we assume $300 per space per year for a 180-space structure, that is $54,000 a year and, grossed up for vacancy, another $39.47 a month per unit. Readers who want the full picture should add it; we left it out of the headline figures so that they can be reproduced from the capital cost alone.
Who pays, and who could
In the model above, the parking is paid for by every tenant through rent, whether or not they own a car. That is the default outcome when parking is bundled with the apartment, and it is the outcome a minimum-parking requirement makes almost certain, since a developer required to build a space for every unit has little reason to price it separately.
The alternative is to unbundle: rent the apartment at one price and the space at another. If the 120 structured spaces in our first example could be leased separately for $183 a month each, the apartments would carry none of the cost, and tenants without cars would pay $183 less. Whether that works depends on whether tenants will actually pay $183 for a space, which depends on how scarce street parking is and how much the neighbors object to cars spilling onto it. In markets where a space rents for far less than it costs to build, unbundling only redistributes the shortfall; it does not eliminate it. The capital is spent either way.
This is the fair case for parking requirements, and it should be stated plainly. Cars parked on the street impose a real cost on neighbors, and a building that provides too little parking exports that cost. A minimum ratio is a blunt way of preventing the export. The question the numbers pose is whether the cost of the blunt instrument, on the order of $90 to $230 a month per apartment in the constrained case above, is proportionate to the harm it prevents, and whether a price on street parking or a lower ratio with unbundled spaces would prevent the same harm more cheaply. Those are questions for the community that owns the streets. The arithmetic only tells them what they are deciding.
Why the number is larger on expensive land
One more effect deserves mention because it is often the largest of all, and we have not modeled it. Parking occupies land. On a small site, a requirement of 1.5 spaces per unit may mean that the number of units that can fit shrinks, because the ground floor is a garage rather than apartments, or because the structure has to be sized for a ratio that only a smaller building can satisfy. When that happens the cost of the requirement is not only the concrete but the units that were never built, and every fixed cost of the project, land above all, is spread across fewer homes. That effect is site-specific and cannot be reduced to a per-space figure. It is discussed in the context of floor area ratio and density in Why Can’t Developers Build Cheaper Apartments?, which runs on Reference Project B, a building that already has its parking in a structure, and so measures the saving from removing spaces rather than the cost of adding them.
Reference Project A (the garden project): an illustrative 120-unit three-storey wood-frame project with 180 surface parking spaces; total development cost $24,265,760 ($202,215 per unit); operating expenses $7,122 per unit per year; required rent $1,995.93 per unit per month, derived in Why a New Apartment Costs $2,000 a Month. Why this project: it parks its cars on asphalt, so the cost of moving them into a structure can be added and measured rather than assumed away. Both reference projects are defined side by side on our Methodology page.
Cost per space: we assume $6,000 for a surface space, $22,000 for a tuck-under or podium space, $27,000 for a space in an above-ground structure, and $50,000 for an underground space. The chart shows the assumed ranges from which these figures were taken ($4,000 to $10,000; $15,000 to $30,000; $20,000 to $40,000; $35,000 to $75,000). These are assumptions, not measured costs, and vary widely by site and market.
Financing: we assume 65 percent loan-to-cost at 6.5 percent with 30-year amortization (mortgage constant 0.075848), 35 percent equity at an 8 percent cash-on-cash yield, and a 5 percent vacancy allowance. Blended annual capital charge 0.077301 per dollar of cost. These are the default assumptions of the Rent Impact tool.
Requirement case: we assume the market choice would be one surface space per unit (120 spaces, $720,000) and the requirement is 1.5 spaces per unit (180 spaces), all of which must be structured ($4,860,000) because the site cannot fit 180 spaces at grade.
Parking operating cost, where mentioned: we assume $300 per space per year; this is excluded from the headline figures.
No parking revenue is assumed; all parking cost is carried by apartment rent unless stated otherwise.
All rent impacts use the shared rent-math method: capital cost × (0.65 × 0.075848 + 0.35 × 0.08) ÷ (1 − 0.05) ÷ 120 units ÷ 12 months. On this project that is $56.51 per month per $1 million of capital. Figures are computed without intermediate rounding and displayed to the cent in tables and to the dollar in prose.
Worked examples: 120 surface spaces, $720,000 × 0.077301 = $55,657 per year ÷ 0.95 ÷ 1,440 = $40.68 per month. 120 structured spaces, $3,240,000 → $250,455 per year → $183.08 per month. 180 structured spaces, $4,860,000 → $375,683 per year → $274.62 per month. The before/after difference, $4,140,000 → $233.94 per month, of which 60 additional spaces ($1,620,000) account for $91.54 and the change of format for the first 120 spaces ($2,520,000) accounts for $142.40.
The model treats parking as a pure cost with no revenue and no effect on the number of units, on the building type, or on land value. Each of those simplifications understates the cost of a requirement on constrained sites and overstates it where parking can be leased separately at a price near its cost.
The per-space costs are stated assumptions rather than observations. They are chosen to reflect the ordering that every developer encounters — surface is cheapest, podium costs more, structured more again, underground most of all — and not to report the price of any particular garage, and no external cost survey was used to set them. Parking construction cost is one of the most locally variable numbers in development, moving with soil conditions, water table, code, and local trade pricing. A reader pricing a real site should get a local estimate and substitute it for ours before reaching a conclusion about that site.
If tenants will pay for parking separately at a price near its cost, the rent impact on the apartments falls toward zero and the cost is borne by the drivers who use the spaces. This is most plausible where street parking is scarce and priced.
If the site has room for the required ratio at grade, the requirement costs $41 a month per space per unit rather than $183 or more, and the argument for and against it is correspondingly smaller.
If financing terms differ from our defaults, every figure scales with the blended capital charge. At a 5.5 percent loan rate the structured-parking impact of $183 becomes about $171; at 7.5 percent, about $196.
If a parking requirement reduces the number of units that fit on a site, the true cost per remaining unit is higher than anything modeled here, because fixed costs are spread across fewer homes.
If a lender or investor would not fund a building without parking regardless of the code, the mandate adds nothing beyond what the market would have required. This is common in car-dependent suburbs and rare in transit-served neighborhoods.
What this means
A parking space is a room with a concrete floor and no tenant, and it is paid for the same way every other room is: through rent, for decades. On a site where cars can sit on asphalt, the cost is small, about $41 a month per space under our assumptions. On a site where they must be stacked, one space per unit adds about $183 a month, and a 1.5-space requirement that forces everything into a structure adds about $234 a month compared with what the market would have built. Below ground, the figures roughly double.
None of this makes parking requirements wrong. It makes them expensive, and it makes the expense specific. A community that requires 1.5 structured spaces per apartment is deciding that preventing spillover onto its streets is worth roughly $234 a month to each household that will live in the building, most of whom have not moved there yet. That may be the right call. It is a call that ought to be made knowing the number.