Highly dense populations are typically great for self-storage businesses, but costs and crazy zoning requirements have left some of the top metros in the country undersupplied when it comes to self-storage.

In a recent report headed by its Self-Storage Valuation Group, CBRE named New York, San Jose, Los Angeles, San Diego and Baltimore as the undersupplying markets, and used its proprietary economic model to measure existing supply per person compared to four demographic variables—population, percent of renters, average household size and average household income.

“A lot of it has to do with zoning and entitlements,” CBRE EVP of self-storage valuation Chris Sonne (pictured) tells Bisnow. “They’re very hard markets to develop in and there’s not a lot of space in these urban areas. It’s also very expensive to build and a lot of the REITs aren’t into the development side because it’s dilutive to their earnings and can take three to five years before they see quarterly dividends.”

Here are some quick stats on the five most undersupplied metros:

New York

SF Per Person: 3.52 SF

Forecast Demand: 3.24

Variance: -0.29

San Jose

SF Per Person: 4.46 SF

Forecast Demand: 5.17

Variance: 0.71

Los Angeles

SF Per Person: 4.72 SF

Forecast Demand: 6.08

Variance: 1.36

San Diego

SF Per Person: 6.22 SF

Forecast Demand: 7.55

Variance: 1.33

Baltimore

SF Per Person: 4.9 SF

Forecast Demand: 5.43

Variance: 0.53