Millions of U.S. Rental Units Are Sitting Empty. Not All of That Is the Market's Doing.

The U.S. rental market has loosened. The Census Bureau put the national rental vacancy rate at 7.3% in the second quarter of 2026, which works out to roughly 3.5 million vacant units across a rental stock of about 48 million. This spring, two in five Zillow listings offered concessions such as free rent or waived fees. Much of that slack has a plain explanation: a record run of apartment completions added supply faster than renters could absorb it.

Not every empty unit is a supply story, though. Some vacancy comes from how units get leased. Asking rents are set too high and adjusted too slowly, inquiries go unanswered, and independent listings can’t compete with professionally managed ones. Unlike new supply, that portion is within an owner’s control, and industry research suggests it is not small. A 2024 secret-shopper study by real estate analyst Mike DelPrete found that 47% of online inquiries in residential real estate got no answer at all. The ones that did get a reply waited more than eight hours on average.

Evgeny Pisarev, founder of Nmbr, sees those failures from the leasing side. Nmbr is one of a number of platforms that automate parts of the leasing process for landlords, from pricing recommendations to follow-up with prospective tenants. Pisarev ranks the operational causes of extended vacancy in a clear order: pricing first, communication speed second, listing quality third. A fourth category, market mismatch, describes a well-priced, well-presented unit that doesn’t fit its area’s renter profile. In his view, it is the hardest to fix and the least common.

Why Pricing Delays Cost Landlords Weeks

The most common reason a unit sits empty, by Pisarev’s account, is mispricing, and more specifically the attachment landlords bring to their asking rent. He describes a San Francisco unit that had rented for $4,000 a month. When the lease ended, the owner listed it at $6,000 and drew no takers. Comparable listings nearby pointed to a lower price. The owner cut the rent, but not far enough.

Testing a higher price is reasonable, Pisarev says. The mistake is how long owners wait to read the result. Early inquiry volume shows how quickly a unit will lease at its current price, and in his view the first 72 hours provide enough of that signal. “Three days is enough to understand how fast it will be rented out,” he says. Most owners, he says, take three to four weeks to act on that information, if they act at all. “In reality, better to make a decision on day three because the information is enough.”

A softer market makes that delay more expensive. With concessions now widespread, a unit priced above its comparables competes not only with lower asking rents but with free months offered down the street.

The Communication Breakdown That Loses Tenants

Pricing determines whether a unit attracts interest. What happens after the inquiry determines whether that interest becomes a lease.

Renters expect fast answers. In Zillow research, 45% of renters who contacted a property manager expected a response within a few hours, and 77% expected one within a day. Missing that window has a measurable cost. According to Pisarev, the drop-off after a single unanswered call can reach 80%, while repeated attempts across calls and messages can bring it down to around 30%.

Keeping up that kind of follow-up by hand is difficult for individual landlords, and even for agents juggling several listings. The burden lies less in any one message than in the tracking around it: who responded, when they can view the unit, which prospects are pre-qualified, and when to try again. A growing number of leasing platforms now automate some or all of that outreach. Even so, Pisarev says, no system reaches every prospect. The difference that matters is between persistent, multi-channel follow-up and a single phone call.

Speed matters at the showing stage too. “If you offer them a visit in seven days, they will not remember what property it was,” Pisarev says. A delayed showing gives a prospective tenant time to commit elsewhere, or simply to forget the listing.

Individual Landlords Competing Against Corporate Operations

The third cause, listing quality, falls hardest on independent owners. Nearly half of U.S. rental units sit in properties of one to four units, a segment where individual landlords are common. Corporate operators typically invest in professional photography, polished descriptions, and consistent listing standards. On listing platforms, an independent owner’s unit appears right beside theirs, and weaker presentation shows immediately.

The larger obstacle, Pisarev says, is that many owners don’t treat any of this as urgent. “People are very diverse in their habits, more diverse than we can imagine,” he says. That unpredictability cuts both ways: tenants who inquire and never answer follow-up, and owners who set up a listing and then don’t manage it.

What the Vacancy Numbers Actually Reflect

Not all of the national figure is reducible, and vacancy varies widely by market. The Census Bureau put Florida’s statewide rental vacancy rate at 10.2% in 2025, against a national rate of 7.2%. New York City’s most recent housing survey found overall rental vacancy below 2%. Market conditions, seasonal patterns, and housing quality all drive those differences, and no amount of faster follow-up fills a unit the market has no tenant for.

Pisarev doesn’t argue otherwise. “It couldn’t be zero – it’s a market, it’s normal, some part of units is free,” he says. But the share of vacancy caused by slow pricing decisions, slow communication, and weak listings can be reduced. In a market where supply has outrun demand, it is the share owners can actually change.

The shift is clearest against recent history. In 2021 and 2022, national vacancy fell to some of its lowest levels in decades. Back then, a unit could be priced high, listed with phone photos, and answered whenever convenient, and it would still lease. With vacancy now well above those lows, the market has stopped absorbing operational mistakes. For small landlords, the cost of a slow decision or an unanswered inquiry is now measured in months of lost rent rather than days.

About the Expert: Evgeny Pisarev is founder of Nmbr, a platform that automates parts of the rental leasing process for landlords, including pricing recommendations and follow-up with prospective tenants.

This article is based on information provided by the expert source cited above. It is intended for general informational purposes only and does not constitute legal, financial, or real estate advice. Readers should conduct their own research and consult qualified professionals before making any real estate or financial decisions.