Millions of homes and condominiums across the country are in high danger zones for environmental hazards.

According to the Environmental Hazards Housing Risk Index, produced by ATTOM Data Solutions, 17.3 million single family homes and condos with a combined estimated market value of $4.9 trillion are in zip codes with high or very high risk for at least one of four environmental hazards: Superfunds, brownfields, polluters or poor air quality.

The 17.3 million single family homes and condos in high-risk zip codes represent 25 percent of the 68.1 million single family homes and condos in the 8,642 zip codes analyzed, according to ATTOM, which manages one of the country’s largest property databases with data on 150 million residential and commercial properties.

Researchers calculated a risk index for each of the four environmental hazards for each of the 8,642 zip codes, and then divided the indexes into five categories of risk: Very Low, Low, Moderate, High and Very High.

Of the 8,642 zip codes analyzed, 6,238 with 50.8 million single family homes and condos (75 percent) worth a combined $16.9 trillion did not have a High or Very High risk index for any of the four environmental hazards.


“Home values are higher and long-term home price appreciation is stronger in zip codes without a high risk for any of the four environmental hazards analyzed,” said Daren Blomquist, senior vice president at ATTOM Data Solutions. “Corresponding to that is a higher share of homes still seriously underwater in the zip codes with a high risk of at least one environmental hazard, indicating those areas have not regained as much of the home value lost during the downturn.

Blomquist said that conversely, home price appreciation over the past five years was actually stronger in the higher-risk zip codes, which he said could reflect the “strong influence of investors” during this recent housing recovery. “Environmental hazards likely impact owner-occupants more directly than investors, making the latter more willing to purchase in higher-risk areas. The higher share of cash sales we’re seeing in high-risk zip codes for environmental hazards also suggests that this is the case,” he added.

Top 10 Environmental Risk Zip Codes

A total environmental hazard index combining the four individual hazard indexes was also calculated for each of the 8,642 zip codes nationwide.

Zip codes with the 10 highest Total Environmental Hazard Index values were in Denver; San Bernardino, California; Curtis Bay, Maryland (in the Baltimore metro area); Santa Fe Springs, California (in the Los Angeles metro area); Fresno, California; Niagara Falls, New York; Saint Louis; Mira Loma, California (in the Riverside-San Bernardino metro area); Hamburg, Pennsylvania (in the Reading metro area); and Tampa, Florida.


Zip CodeCityStateOverall Risk Index2016 Median Sales Prices5-Year HPAHome Seller Pct GainPct Seriously UnderwaterForeclosure Rate
92408San BernardinoCA400$197,500105.7%36.2%13.3%0.6%
21226Curtis BayMD380$153,8222.5%3.4%14.4%0.7%
90670Santa Fe SpringsCA356$435,00052.6%36.4%3.4%0.5%
14303Niagara FallsNY294$27,750-0.9%13.3%10.8%0.2%
63133Saint LouisMO291$17,000-2.9%-55.0%45.4%0.2%
91752Mira LomaCA291$425,00070.3%54.5%3.4%0.3%



For the report, ATTOM Data Solutions analyzed 8,642 U.S. zip codes with sufficient housing trend data for the following four environmental hazards: poor air quality, superfund sites, polluters, brownfields and former drug labs.

A housing risk index was calculated for each of the four types of hazards in each of the 8,642 zip codes. The maximum index value for each index was 250 and the minimum value was 0.

A combined environmental hazard index comprised of these four factors and with a maximum possible score of 1,000 was assigned to each zip code. The highest actual score for any zip code was 455. Each individual natural hazard index accounted for 25 percent of the combined index.

Irvine, Calif- based ATTOM Data Solutions, in addition to being curator of the ATTOM Data Warehouse, publishes searchable consumer real estate websites including, and

Source: Environmental Hazards Housing Risk Index