Nation’s Green Leaders: Hawaii, D.C. and Vermont Shine in Environmental Rankings
Sustainability has been a major focus among some states for years. While those efforts are in full bloom in some states, they’re barely a blossom in others.
We evaluated five metrics to rank the greenest states: solar net summer capacity, carbon dioxide releases, electric vehicle (EV) adoption rates, average daily air quality index (AQI) figures and the percentage of public water systems with averages higher than the maximum contaminant levels (MCLs).
In addition to reviewing our findings, stick around for tips on utilizing home insurance to help offset the costs of going green.
Key findings
- Hawaii, the District of Columbia and Vermont are the greenest U.S. states. Hawaii — one of 11 states where 0% of public water systems have averages exceeding maximum contaminant levels (MCLs) — has top-five finishes in four of our five metrics. The District of Columbia has three top-one finishes but is hurt by its solar net summer capacity. Vermont is also tied for No. 1 in our water metric — part of four top-seven finishes.
- West Virginia, Nebraska and Kentucky are the least green states in the U.S. West Virginia is weighed down by three bottom-10 finishes, including having the fourth-worst carbon dioxide (CO2) emissions. Nebraska and Kentucky are also in the bottom 10 three times, led by having the fifth-worst and third-worst solar net summer capacities.
- Nevada has the largest solar net summer capacity by a wide margin. Nevada has a net summer capacity — how much solar power plants can supply at the summer peak — of 193.1 megawatts per 100,000 residents, far ahead of New Mexico at 104.9 — the only other state above 100.0 in this category. The next closest is California at 98.4. For comparison, the U.S. average (among available states) is 46.5.
- The District of Columbia and California have electric vehicle (EV) adoption rates more than double the national average. D.C. and California have EV adoption rates of 9.6% and 9.1% based on registrations, with the U.S. average at 4.3%. Washington joins them in the top three at 7.3%.
- 11 states tie for the highest water quality. The 11 states with 0% of public water systems having averages exceeding MCLs are Arkansas, the District of Columbia, Hawaii, Iowa, Louisiana, Maine, Mississippi, Montana, New Mexico, North Dakota and Vermont.
How did we determine the greenest states?
To determine the greenest states, LendingTree researchers evaluated the following categories and used the following percentage weights:
- Solar net summer capacity from utility and small-scale facilities (megawatts per 100,000 residents) (30% of total calculations)
- Energy-related carbon dioxide (CO2) emissions (metric tons per capita) (25%)
- Electric vehicle adoption rates (25%)
- Average daily air quality index (AQI) score for PM2.5 (fine particulate matter) (10%)
- Percentage of public water systems with averages higher than the maximum contaminant levels (MCLs) (10%)
The date of the latest data available varied by source used. For a full breakdown, see the methodology.
With clean public water, Hawaii is greenest state
By state, Hawaii is the greenest. Notably, it’s one of 11 states where 0% of public water systems exceed the maximum contaminant levels (MCLs). According to the Environmental Protection Agency (EPA), an MCL is the highest level of a contaminant allowed in drinking water. The contaminants analyzed include 29 per- and polyfluoroalkyl substances (PFAS) and lithium.
Overall, Hawaii ranks in the top five in four out of five metrics. Beyond its public water system ranking, Hawaii has the:
- Third-highest air quality index (AQI) score for PM2.5 (fine particulate matter), at 14.1. A score between zero and 50 is considered good air quality.
- Fourth-highest solar net summer capacity (the amount of solar power that can be supplied at the summer peak by power plants), at 94.9 megawatts per 100,000 residents.
- Fifth-highest electric vehicle (EV) adoption rate, at 6.4%.
3 greenest states
| Rank | State | Solar net summer capacity (megawatts per 100,000 residents) | CO2 emissions (metric tons per capita) | EV adoption rate | Average daily AQI score for PM2.5 | % of public water facilities with average above MCLs | Score |
|---|---|---|---|---|---|---|---|
| 1 | Hawaii | 94.9 | 12.0 | 6.4% | 14.1 | 0% | 7.9 |
| 2 | District of Columbia | 27.9 | 3.8 | 9.6% | 0% | 8.1 | |
| 3 | Vermont | 50.6 | 8.6 | 5.7% | 18.0 | 0% | 8.3 |
Source: LendingTree analysis of various sources. Notes: The composite uses weighted scoring: Solar capacity (30%), CO2 emissions (25%), EV adoption rates (25%), air quality (10%) and water quality (10%). D.C. didn’t have available air quality data.
The District of Columbia ranks second. It ranks first in CO2 emissions, releasing just 3.8 metric tons per capita (compared to a U.S. average of 14.8). It also ranks first in EV adoption rate, at 9.6%, and is one of the 11 states where 0% of public water systems have contaminants exceeding MCLs.
Vermont finishes third. It’s also tied for No. 1 in our water quality metric. Additionally, it ranks sixth for CO2 emissions (releasing 8.6 metric tons per capita), sixth for EV adoption rate (at 5.7%) and seventh for air quality (at an average daily AQI of 18.0).
All three top-ranking states have good water quality, and LendingTree home insurance expert and licensed insurance agent Rob Bhatt says that can indirectly impact insurance rates.
“Having access to quality water is a great benefit for any homeowner,” he says. “While your region’s water quality doesn’t directly impact your insurance rate, there may be an indirect link between high water quality and low insurance rates. States like Vermont and Hawaii don’t have as much industry and traffic congestion as more densely populated areas, which tend to have lower-quality water. The average cost of home insurance in Hawaii is about a quarter of the national average. Vermont homeowners pay about half the national average for home insurance.”
West Virginia is least green state
Conversely, West Virginia is the least sustainable state. Most notably, it has the fourth-worst carbon dioxide (CO2) emissions, releasing 49.5 metric tons per capita. It also has the:
Seventh-worst solar net summer capacity, at 9.0 megawatts per 100,000 residents.Eighth-worst EV adoption rate, at 1.8%.
3 least green states
| Rank | State | Solar net summer capacity (megawatts per 100,000 residents) | CO2 emissions (metric tons per capita) | EV adoption rate | Average daily AQI score for PM2.5 | % of public water facilities with average above MCLs | Score |
|---|---|---|---|---|---|---|---|
| 1 | West Virginia | 9.0 | 49.5 | 1.8% | 26.6 | 13% | 42.4 |
| 2 | Nebraska | 7.9 | 24.0 | 2.2% | 28.5 | 10% | 41.0 |
| 3 | Kentucky | 5.4 | 24.7 | 2.1% | 29.9 | 4% | 40.9 |
Source: LendingTree analysis of various sources. Note: The composite uses weighted scoring: Solar capacity (30%), CO2 emissions (25%), EV adoption rates (25%), air quality (10%) and water quality (10%).
Nebraska follows, ranking fifth-worst for solar net summer capacity (at 7.9 megawatts per 100,000 residents), 10th-worst for EV adoption rate (at 2.2%) and ninth-worst for CO2 emissions (at 24.0 metric tons per capita).
Kentucky rounds out the bottom three. It ranks third-worst for solar net summer capacity (at 5.4 megawatts per 100,000 residents), seventh-worst for CO2 emissions (at 24.7 metric tons per capita) and ninth-worst for EV adoption rate (at 2.1%).
How do insurance rates factor in? Nebraska and Kentucky have particularly high home insurance rates, but that’s primarily due to the tornado and severe storm risks in these states. Events that cause mass damage tend to cost insurance companies the most.
Full rankings
Most green/least green states
| Rank | State | Solar net summer capacity (megawatts per 100,000 residents) | CO2 emissions (metric tons per capita) | EV adoption rate | Average daily AQI score for PM2.5 | % of public water facilities with average above MCLs | Score |
|---|---|---|---|---|---|---|---|
| 1 | Hawaii | 94.9 | 12.0 | 6.4% | 14.1 | 0% | 7.9 |
| 2 | District of Columbia | 27.9 | 3.8 | 9.6% | 0% | 8.1 | |
| 3 | Vermont | 50.6 | 8.6 | 5.7% | 18.0 | 0% | 8.3 |
| 4 | Maine | 92.4 | 10.5 | 3.9% | 18.7 | 0% | 10.7 |
| 5 | California | 98.4 | 8.3 | 9.1% | 40.5 | 17% | 11.1 |
| 6 | Massachusetts | 60.9 | 8.0 | 5.6% | 24.1 | 20% | 12.1 |
| 7 | Nevada | 193.1 | 12.5 | 5.0% | 26.3 | 6% | 12.8 |
| 8 | Oregon | 34.5 | 9.1 | 6.5% | 20.3 | 9% | 13.9 |
| 9 | Virginia | 52.4 | 11.3 | 4.4% | 19.8 | 6% | 15.5 |
| 10 | Maryland | 27.9 | 8.5 | 5.4% | 12.3 | 31% | 15.7 |
| 11 | Colorado | 56.7 | 14.7 | 5.2% | 23.7 | 5% | 16.2 |
| 12 | New York | 26.4 | 7.9 | 4.7% | 19.1 | 10% | 16.3 |
| 13 | Rhode Island | 79.6 | 9.7 | 3.8% | 22.3 | 27% | 16.7 |
| 14 | Arizona | 94.6 | 11.4 | 4.5% | 45.4 | 15% | 18.1 |
| 15 | New Jersey | 38.3 | 9.6 | 4.8% | 25.4 | 46% | 18.2 |
| 16 | Utah | 80.2 | 18.6 | 4.4% | 29.4 | 2% | 18.3 |
| 17 | New Mexico | 104.9 | 21.7 | 3.0% | 26.5 | 0% | 19.6 |
| 18 | Washington | 8.6 | 9.5 | 7.3% | 21.1 | 10% | 20.5 |
| 18 | Florida | 54.4 | 10.4 | 3.9% | 31.6 | 37% | 20.5 |
| 18 | Connecticut | 37.5 | 10.1 | 4.3% | 26.1 | 48% | 20.5 |
| 21 | North Carolina | 67.0 | 10.9 | 3.4% | 35.4 | 18% | 21.8 |
| 22 | Idaho | 34.0 | 10.8 | 2.9% | 32.8 | 5% | 23.9 |
| 23 | New Hampshire | 18.4 | 9.6 | 3.9% | 21.5 | 24% | 24.5 |
| 24 | Georgia | 41.8 | 11.5 | 3.0% | 44.8 | 11% | 25.3 |
| 25 | Wisconsin | 35.8 | 15.7 | 2.9% | 23.8 | 8% | 25.5 |
| 25 | North Dakota | 72.7 | 1.3% | 15.4 | 0% | 25.5 | |
| 27 | Texas | 67.7 | 22.4 | 2.8% | 32.9 | 3% | 25.9 |
| 27 | Illinois | 20.8 | 14.5 | 4.2% | 31.1 | 3% | 25.9 |
| 29 | Minnesota | 27.3 | 14.6 | 3.5% | 28.4 | 8% | 26.5 |
| 30 | Delaware | 22.8 | 12.9 | 3.8% | 24.8 | 45% | 27.7 |
| 31 | Alabama | 21.5 | 1.7% | 31.0 | 11% | 28.0 | |
| 32 | Arkansas | 42.7 | 20.5 | 1.7% | 31.0 | 0% | 28.8 |
| 33 | Michigan | 12.5 | 14.7 | 2.7% | 19.4 | 1% | 29.5 |
| 34 | Pennsylvania | 13.0 | 16.4 | 3.5% | 17.8 | 18% | 29.7 |
| 35 | Montana | 21.7 | 25.8 | 2.8% | 22.9 | 0% | 31.3 |
| 36 | South Carolina | 36.8 | 13.4 | 2.2% | 37.8 | 30% | 31.8 |
| 37 | Indiana | 27.7 | 24.4 | 2.6% | 25.9 | 4% | 32.3 |
| 38 | Ohio | 24.1 | 16.5 | 2.7% | 36.0 | 8% | 32.8 |
| 39 | Wyoming | 44.8 | 94.3 | 1.6% | 7.5 | 10% | 32.9 |
| 40 | Iowa | 19.6 | 22.9 | 2.3% | 27.0 | 0% | 34.2 |
| 41 | Tennessee | 9.1 | 13.3 | 2.4% | 31.4 | 7% | 34.3 |
| 42 | Missouri | 9.2 | 19.0 | 2.7% | 31.5 | 6% | 34.7 |
| 43 | South Dakota | 23.2 | 16.9 | 1.6% | 33.1 | 5% | 35.3 |
| 44 | Mississippi | 26.3 | 21.4 | 1.2% | 34.8 | 0% | 35.4 |
| 45 | Kansas | 4.7 | 20.3 | 2.6% | 22.3 | 6% | 36.0 |
| 46 | Oklahoma | 7.4 | 22.0 | 2.6% | 34.3 | 5% | 38.6 |
| 47 | Alaska | 3.7 | 53.0 | 2.5% | 16.5 | 9% | 40.0 |
| 48 | Louisiana | 18.6 | 40.8 | 1.4% | 47.5 | 0% | 40.2 |
| 49 | Kentucky | 5.4 | 24.7 | 2.1% | 29.9 | 4% | 40.9 |
| 50 | Nebraska | 7.9 | 24.0 | 2.2% | 28.5 | 10% | 41.0 |
| 51 | West Virginia | 9.0 | 49.5 | 1.8% | 26.6 | 13% | 42.4 |
Source: LendingTree analysis of various sources. Notes: The composite uses weighted scoring: Solar capacity (30%), CO2 emissions (25%), EV adoption rates (25%), air quality (10%) and water quality (10%). North Dakota and Alabama didn’t have available solar capacity data, while D.C. didn’t have available air quality data.
Nevada could take biggest advantage of ample sunshine
It’s not the Sunshine State, but Nevada could harness enough solar power to give Florida a run for its money.
Nevada has a net summer capacity of 193.1 megawatts per 100,000 residents. New Mexico is the only other state above 100.0, at 104.9.
Note: Because energy demand is often highest in the summer, when temperatures are at their highest, tracking summer capacity gauges whether solar power can meet peak demand. Additionally, because the days are longer and the sun is higher in the sky, tracking allows for an accurate assessment of how much electricity a solar energy system can produce during this period.
Top 3: Solar net summer capacity (megawatts per 100,000 residents) by state
| Rank | State | Solar net summer capacity |
|---|---|---|
| 1 | Nevada | 193.1 |
| 2 | New Mexico | 104.9 |
| 3 | California | 98.4 |
Source: LendingTree analysis of U.S. Energy Information Administration (EIA) data.
Following that, California could harvest 98.4 megawatts per 100,00 residents. The U.S. average (incorporating states with available data) is 46.5.
Between July 2023 and 2024, South Dakota saw the biggest increase in solar net summer capacity, increasing 7,258.6% (not a typo) from 0.3 to 23.2 megawatts per 100,000 residents. That’s followed by West Virginia — jumping 405.1% from 1.8 to 9.0 — and Louisiana — jumping 162.1% from 7.1 to 18.6.
An area’s power sources only have a minimal impact on homeowners insurance, but Bhatt says your risk of fire or damage is lower with solar power. “Natural gas is flammable, which makes it a little riskier than electricity,” he says. “However, you’ll pay about the same for home insurance whether you have electricity or natural gas. On the other hand, you’ll pay more if your home is heated by burning wood or oil, or your application may be denied.”
Full rankings
Solar net summer capacity (megawatts per 100,000 residents) by state
| Rank | State | Solar net summer capacity |
|---|---|---|
| 1 | Nevada | 193.1 |
| 2 | New Mexico | 104.9 |
| 3 | California | 98.4 |
| 4 | Hawaii | 94.9 |
| 5 | Arizona | 94.6 |
| 6 | Maine | 92.4 |
| 7 | Utah | 80.2 |
| 8 | Rhode Island | 79.6 |
| 9 | Texas | 67.7 |
| 10 | North Carolina | 67.0 |
| 11 | Massachusetts | 60.9 |
| 12 | Colorado | 56.7 |
| 13 | Florida | 54.4 |
| 14 | Virginia | 52.4 |
| 15 | Vermont | 50.6 |
| 16 | Wyoming | 44.8 |
| 17 | Arkansas | 42.7 |
| 18 | Georgia | 41.8 |
| 19 | New Jersey | 38.3 |
| 20 | Connecticut | 37.5 |
| 21 | South Carolina | 36.8 |
| 22 | Wisconsin | 35.8 |
| 23 | Oregon | 34.5 |
| 24 | Idaho | 34.0 |
| 25 | District of Columbia | 27.9 |
| 25 | Maryland | 27.9 |
| 27 | Indiana | 27.7 |
| 28 | Minnesota | 27.3 |
| 29 | New York | 26.4 |
| 30 | Mississippi | 26.3 |
| 31 | Ohio | 24.1 |
| 32 | South Dakota | 23.2 |
| 33 | Delaware | 22.8 |
| 34 | Montana | 21.7 |
| 35 | Illinois | 20.8 |
| 36 | Iowa | 19.6 |
| 37 | Louisiana | 18.6 |
| 38 | New Hampshire | 18.4 |
| 39 | Pennsylvania | 13.0 |
| 40 | Michigan | 12.5 |
| 41 | Missouri | 9.2 |
| 42 | Tennessee | 9.1 |
| 43 | West Virginia | 9.0 |
| 44 | Washington | 8.6 |
| 45 | Nebraska | 7.9 |
| 46 | Oklahoma | 7.4 |
| 47 | Kentucky | 5.4 |
| 48 | Kansas | 4.7 |
| 49 | Alaska | 3.7 |
Source: LendingTree analysis of U.S. Energy Information Administration (EIA) data. Note: North Dakota and Alabama didn’t have available solar capacity data.
District of Columbia, California dominate EV adoption
When it comes to going electric, the District of Columbia has the highest EV adoption rate (the percentage of EV registrations among light-duty vehicle registrations), at 9.6%. California follows at 9.1%. Both states have more than double the national average adoption rate of 4.3%.
The District of Columbia and California are well set up for EV adoption. A LendingTree study on EV infrastructure found that the District of Columbia has the most public electric vehicle charging ports per 10,000 drivers and California has the most electric vehicle laws and incentives.
Washington ranks third at 7.3%.
Top 3: Electric vehicle (EV) adoption rate by state
| Rank | State | EV registrations | Light-duty vehicle registrations | EV adoption rate |
|---|---|---|---|---|
| 1 | District of Columbia | 29,900 | 3,12,100 | 9.6% |
| 2 | California | 33,70,500 | 3,68,50,300 | 9.1% |
| 3 | Washington | 5,00,500 | 68,16,100 | 7.3% |
Source: LendingTree analysis of U.S. Department of Energy Alternative Fuels Data Center data.
Installing an EV charging station at your home usually only has a minimum impact on your homeowners insurance, Bhatt says, but a charging station is another fixture that adds to the amount of dwelling coverage you need.
“If you insure your home for $250,000, you may have to increase your coverage to $260,000 after you install a charging station,” he says. “In most cases, this only adds a few extra bucks to your monthly insurance payment. However, it’s important to make sure a licensed professional installs your charger and that your home’s electrical system is up to current codes. If this requires you to update your home’s electrical system, your insurance company may give you a discount after you complete the upgrades.”
Conversely, Mississippi (1.2%), North Dakota (1.3%) and Louisiana (1.4%) have the lowest adoption rates by state.
Full rankings
Electric vehicle (EV) adoption rate by state
| Rank | State | EV registrations | Light-duty vehicle registrations | EV adoption rate |
|---|---|---|---|---|
| 1 | District of Columbia | 29,900 | 3,12,100 | 9.6% |
| 2 | California | 33,70,500 | 3,68,50,300 | 9.1% |
| 3 | Washington | 5,00,500 | 68,16,100 | 7.3% |
| 4 | Oregon | 2,50,100 | 38,32,700 | 6.5% |
| 5 | Hawaii | 69,300 | 10,80,100 | 6.4% |
| 6 | Vermont | 33,800 | 5,93,100 | 5.7% |
| 7 | Massachusetts | 3,04,900 | 54,91,100 | 5.6% |
| 8 | Maryland | 2,72,100 | 50,60,000 | 5.4% |
| 9 | Colorado | 2,80,300 | 54,41,800 | 5.2% |
| 10 | Nevada | 1,27,600 | 25,56,100 | 5.0% |
| 11 | New Jersey | 3,49,900 | 73,24,100 | 4.8% |
| 12 | New York | 5,37,600 | 1,13,18,600 | 4.7% |
| 13 | Arizona | 2,91,100 | 65,29,000 | 4.5% |
| 14 | Utah | 1,36,200 | 30,76,200 | 4.4% |
| 14 | Virginia | 3,41,100 | 77,23,500 | 4.4% |
| 16 | Connecticut | 1,25,300 | 29,45,700 | 4.3% |
| 17 | Illinois | 4,18,400 | 1,00,43,200 | 4.2% |
| 18 | Maine | 48,600 | 12,36,000 | 3.9% |
| 18 | Florida | 7,26,700 | 1,85,83,200 | 3.9% |
| 18 | New Hampshire | 53,300 | 13,83,700 | 3.9% |
| 21 | Delaware | 35,100 | 9,14,700 | 3.8% |
| 21 | Rhode Island | 33,600 | 8,77,600 | 3.8% |
| 23 | Pennsylvania | 3,54,500 | 1,02,11,000 | 3.5% |
| 23 | Minnesota | 1,77,700 | 51,18,500 | 3.5% |
| 25 | North Carolina | 3,04,500 | 90,85,500 | 3.4% |
| 26 | New Mexico | 59,500 | 19,52,400 | 3.0% |
| 26 | Georgia | 2,90,400 | 96,42,400 | 3.0% |
| 28 | Wisconsin | 1,61,000 | 55,29,000 | 2.9% |
| 28 | Idaho | 56,800 | 19,74,600 | 2.9% |
| 30 | Texas | 7,30,500 | 2,57,96,600 | 2.8% |
| 30 | Montana | 28,200 | 10,21,700 | 2.8% |
| 32 | Missouri | 1,54,700 | 56,26,000 | 2.7% |
| 32 | Michigan | 2,27,500 | 85,25,400 | 2.7% |
| 32 | Ohio | 2,74,200 | 1,03,17,300 | 2.7% |
| 35 | Oklahoma | 1,12,200 | 42,87,900 | 2.6% |
| 35 | Kansas | 67,300 | 26,21,100 | 2.6% |
| 35 | Indiana | 1,58,100 | 61,72,100 | 2.6% |
| 38 | Alaska | 14,200 | 5,59,800 | 2.5% |
| 39 | Tennessee | 1,57,500 | 65,38,800 | 2.4% |
| 40 | Iowa | 72,300 | 31,53,300 | 2.3% |
| 41 | South Carolina | 1,13,000 | 50,42,400 | 2.2% |
| 41 | Nebraska | 43,300 | 19,71,200 | 2.2% |
| 43 | Kentucky | 84,300 | 40,39,700 | 2.1% |
| 44 | West Virginia | 27,000 | 15,10,900 | 1.8% |
| 45 | Arkansas | 47,300 | 27,08,300 | 1.7% |
| 45 | Alabama | 82,100 | 48,35,900 | 1.7% |
| 47 | South Dakota | 14,900 | 9,18,000 | 1.6% |
| 47 | Wyoming | 10,300 | 6,52,900 | 1.6% |
| 49 | Louisiana | 52,400 | 37,74,200 | 1.4% |
| 50 | North Dakota | 10,000 | 7,97,400 | 1.3% |
| 51 | Mississippi | 33,800 | 27,23,300 | 1.2% |
Source: LendingTree analysis of U.S. Department of Energy Alternative Fuels Data Center data.
Water quality highest in 11 states
When it comes to water quality, 11 states tie for the highest: Arkansas, the District of Columbia, Hawaii, Iowa, Louisiana, Maine, Mississippi, Montana, New Mexico, North Dakota and Vermont.
Across the U.S., the percentage of public water facilities above MCLs is 11%. With these 11 states having 0% of water facilities above MCLs, none (or few) have higher levels of 29 per- and polyfluoroalkyl substances (PFAS) and lithium than what’s allowed.
Top: % of public water facilities with maximum contaminant levels above U.S. average by state
| Rank | State | % of public water facilities above maximum contaminant levels | Difference from U.S. average (percentage points) |
|---|---|---|---|
| 1 | Arkansas | 0% | -11 |
| 1 | District of Columbia | 0% | -11 |
| 1 | Hawaii | 0% | -11 |
| 1 | Iowa | 0% | -11 |
| 1 | Louisiana | 0% | -11 |
| 1 | Maine | 0% | -11 |
| 1 | Mississippi | 0% | -11 |
| 1 | Montana | 0% | -11 |
| 1 | New Mexico | 0% | -11 |
| 1 | North Dakota | 0% | -11 |
| 1 | Vermont | 0% | -11 |
Source: LendingTree analysis of Environmental Protection Agency (EPA) Regulated Contaminant Summary data.
Meanwhile, Connecticut has the worst water quality, with 48% of public water facilities above maximum contaminant levels. That’s 37 percentage points above the U.S. average of 11%. That’s followed by New Jersey (at 46%, or 35 points above the U.S. average) and Delaware (at 45%, or 34 percentage points above average).
That means residents in these states have higher exposure to dangerous chemicals. PFAS — known as “forever chemicals” — are linked to developmental issues in pregnancy, cancer, liver problems, immune problems, thyroid problems and more, according to the California State Water Resources Control Board. Not much is known about the adverse effects of lithium in drinking water, but by studying lithium exposure in medication, we know overexposure can cause thyroid or kidney problems.
Full rankings
% of public water facilities with maximum contaminant levels above U.S. average by state
| Rank | State | % of public water facilities above maximum contaminant levels | Difference from U.S. average (percentage points) |
|---|---|---|---|
| 1 | Arkansas | 0% | -11 |
| 1 | District of Columbia | 0% | -11 |
| 1 | Hawaii | 0% | -11 |
| 1 | Iowa | 0% | -11 |
| 1 | Louisiana | 0% | -11 |
| 1 | Maine | 0% | -11 |
| 1 | Mississippi | 0% | -11 |
| 1 | Montana | 0% | -11 |
| 1 | New Mexico | 0% | -11 |
| 1 | North Dakota | 0% | -11 |
| 1 | Vermont | 0% | -11 |
| 12 | Michigan | 1% | -10 |
| 13 | Utah | 2% | -9 |
| 14 | Illinois | 3% | -8 |
| 14 | Texas | 3% | -8 |
| 16 | Indiana | 4% | -7 |
| 16 | Kentucky | 4% | -7 |
| 18 | Colorado | 5% | -6 |
| 18 | Idaho | 5% | -6 |
| 18 | Oklahoma | 5% | -6 |
| 18 | South Dakota | 5% | -6 |
| 22 | Kansas | 6% | -5 |
| 22 | Missouri | 6% | -5 |
| 22 | Nevada | 6% | -5 |
| 22 | Virginia | 6% | -5 |
| 26 | Tennessee | 7% | -4 |
| 27 | Minnesota | 8% | -3 |
| 27 | Ohio | 8% | -3 |
| 27 | Wisconsin | 8% | -3 |
| 30 | Alaska | 9% | -2 |
| 30 | Oregon | 9% | -2 |
| 32 | Nebraska | 10% | -1 |
| 32 | New York | 10% | -1 |
| 32 | Washington | 10% | -1 |
| 32 | Wyoming | 10% | -1 |
| 36 | Alabama | 11% | 0 |
| 36 | Georgia | 11% | 0 |
| 38 | West Virginia | 13% | 2 |
| 39 | Arizona | 15% | 4 |
| 40 | California | 17% | 6 |
| 41 | North Carolina | 18% | 7 |
| 41 | Pennsylvania | 18% | 7 |
| 43 | Massachusetts | 20% | 9 |
| 44 | New Hampshire | 24% | 13 |
| 45 | Rhode Island | 27% | 16 |
| 46 | South Carolina | 30% | 19 |
| 47 | Maryland | 31% | 20 |
| 48 | Florida | 37% | 26 |
| 49 | Delaware | 45% | 34 |
| 50 | New Jersey | 46% | 35 |
| 51 | Connecticut | 48% | 37 |
Source: LendingTree analysis of Environmental Protection Agency (EPA) Regulated Contaminant Summary data.
Using home insurance to help go green: Top expert tips
Protecting the environment is a noble goal. However, going green isn’t a top priority for insurers. That said, Bhatt says some insurance companies offer discounts for sustainable homes.
“In some parts of the country, you can get a home insurance discount for upgrading to wind- and hail-resistant windows and roofs,” Bhatt says. “The windows, in particular, can make your home a little more energy-efficient. However, these types of upgrades do more to protect you from the environment than they do to protect the environment.”
There are other financial benefits of making your home more eco-friendly, too.
“Installing solar panels, for example, can reduce your energy costs and increase the resale value of your home,” he says. “Weather-proofing your home and replacing old appliances with energy-efficient new ones provide additional ways to save on energy costs while lowering your carbon footprint.”
Methodology
LendingTree researchers analyzed various sources to create a composite ranking of the greenest U.S. states.
The categories evaluated (based on the latest available data), as well as their percentage weight, were:
- Solar net summer capacity from utility and small-scale facilities (megawatts per 100,000 residents) (30%)
- Energy-related carbon dioxide (CO2) emissions (metric tons per capita) (25%)
- Electric vehicle adoption rates (25%)
- Average daily air quality index (AQI) score for PM2.5 (10%)
- Percentage of public water systems with averages higher than the maximum contaminant levels (MCLs) (10%)
Researchers analyzed July 2024 U.S. Energy Information Administration (EIA) data on solar net summer capacity in each state. We divided each state’s capacity (in megawatts) by its population and multiplied that figure by 100,000. Data for Alabama and North Dakota wasn’t available. Additionally, we utilized 2021 EIA data on per capita energy-related CO2 emissions in each state.
Researchers used 2023 U.S. Department of Energy Alternative Fuels Data Center data to create an electric vehicle adoption rate in each state. We added a state’s electric, plug-in hybrid and hybrid electric vehicle registrations and divided them by the state’s total light-duty vehicle registrations.
Using AirNow, researchers averaged daily air quality index (AQI) scores for fine particulate matter (PM2.5). The average for each state was calculated using all available reporting areas on Sept. 25, 2024. Data for the District of Columbia wasn’t available.
Finally, we used Environmental Protection Agency (EPA) Regulated Containment Summary data as of July 11, 2024, on the percentage of public water systems with averages exceeding the maximum contaminant levels (MCLs).
Population data is from the U.S. Census Bureau Vintage 2023 (covering 2020 to 2023) annual estimates.