How many EV bays does a 400-bay car park need in 2026?

Key Takeaways

• EV bay requirements are set locally, not globally, and the range across published codes runs from roughly 2% of spaces (Orlando's ordinance) up to 35-50% for clean-air-vehicle-ready spaces under stricter tiers (California CALGreen).
• Multi-family residential codes commonly land around 10% EV-capable, a figure that shows up in both California's CALGreen baseline and Washington State's accessible-parking EV rule.
• "EV-capable," "EV-ready," and "EV charging station installed" are three different, cumulative tiers, not synonyms, and confusing them is the most common way a car park under-provisions.
• For a 400-bay car park, a 10% EV-capable baseline works out to 40 bays with electrical infrastructure roughed in, a meaningfully different (and cheaper) commitment than 40 bays with chargers actually installed on day one.

There's no universal answer to "how many EV bays does a 400-bay car park need," because unlike a fire-safety or structural code, EV charging requirements are set locally and vary by a factor of ten or more between jurisdictions. The right number for a specific car park depends on which code applies to it, and on which of three distinct provisioning tiers that code is actually asking for.

The tiers that get conflated: capable, ready, and installed

"EV-capable" typically means the electrical infrastructure, conduit, panel capacity, is roughed in during construction so a charger can be added later without major rework, but no charger or even a full circuit is installed yet. "EV-ready" usually means a complete circuit exists, wiring and panel capacity provisioned, requiring only the charging unit itself to be installed. "EV charging station installed" means an operational charger is already on site.

New Jersey's rule illustrates the distinction directly: new multi-family developments with 5 or more units must designate 15% of off-street parking as EV "make-ready" spaces (Climate Policy Dashboard, EV infrastructure requirements, retrieved 2026-09-10), specifically the middle tier, not fully installed chargers. Reading a percentage requirement without checking which tier it refers to is the single most common way a project either over-builds (installing chargers where roughed-in capacity would have satisfied the code) or under-builds (assuming "EV-capable" satisfies a rule that actually demands "EV-ready").

The range across published codes

California's CALGreen code sets a straightforward multi-family baseline: 10% of spaces designated EV-capable (UpCodes, EV charging code summary, retrieved 2026-09-10). For nonresidential projects under CALGreen's stricter tiers, the requirement jumps sharply: Tier 1 reserves 35% of spaces for clean-air vehicles, Tier 2 reserves 50%, met through a mix of EV-capable spaces and a power-allocation option (UpCodes, retrieved 2026-09-10).

Washington State's rule ties EV requirements to accessible parking specifically: 10% of accessible spaces must be EV charging stations (fully installed), with an additional 10% of accessible spaces required to be EV-ready (Washington State Legislature, WAC 51-50-0429, retrieved 2026-09-10). Orlando's ordinance sits at the low end of the range: 2% of all new parking spaces equipped with charging stations, with a further 10-20% required to be EV-capable (Climate Policy Dashboard, retrieved 2026-09-10).

Running the range against a 400-bay car park

Applying these benchmarks to a 400-bay facility shows how differently the same car park could be provisioned depending on which code frame it's measured against: a 2% installed-charger minimum is 8 bays; a 10% EV-capable baseline is 40 bays; a 15% make-ready requirement is 60 bays; a 35-50% clean-air-vehicle tier is 140-200 bays. These aren't rounding differences, they're order-of-magnitude differences in both capital cost and how much of the car park needs electrical work at all. Run a specific facility's applicable local requirement and expected EV adoption curve through the EV bay capacity calculator rather than assuming a percentage from a different jurisdiction transfers directly.

Provisioning ahead of the requirement, deliberately

Because "EV-capable" is materially cheaper than "EV-ready," which is in turn cheaper than a fully installed charger, the common and lower-regret strategy is to rough in capacity (conduit, panel headroom) across a wider share of bays than the current code strictly requires, while installing actual chargers only where near-term demand justifies it. This avoids the far more expensive alternative: retrofitting conduit through a fully finished car park once demand for chargers exceeds what was built in. A group EV charging solutions review is a reasonable next step for a facility deciding how much conduit and panel headroom to rough in now against demand that hasn't arrived yet.

Frequently asked questions

Is there one correct number of EV bays for a 400-bay car park?

No. The correct number depends entirely on the local code that applies to that specific car park, and codes range from roughly 2% to 50% of spaces depending on jurisdiction, building type, and which provisioning tier (capable, ready, installed) is being measured.

What's the practical difference between "EV-capable" and "EV-ready"?

EV-capable means the electrical infrastructure is roughed in (conduit, panel capacity) for future installation. EV-ready means a complete circuit already exists, so only the charging unit needs to be added. The cost difference between the two is significant, and codes specify one or the other, not interchangeably.

Is it worth provisioning more bays than the current code requires?

Often yes, for the cheapest tier (EV-capable), since retrofitting conduit through a finished car park later is far more expensive than roughing it in during initial construction. This is a different decision from installing actual chargers ahead of demand, which ties up capital in unused hardware.

The bottom line

"How many EV bays does a 400-bay car park need" isn't answerable without first establishing which jurisdiction's code applies and which of the three provisioning tiers it specifies. Once those two things are known, the number falls out of a published percentage, but skipping that step and applying a benchmark from the wrong jurisdiction or the wrong tier is the most common sizing mistake.

Figures were verified on 10 September 2026 against published US state and municipal EV charging infrastructure codes. Requirements vary by jurisdiction and change over time; confirm the specific code applicable to your project's location before finalising a bay count.