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Water quality can vary significantly based on city size. Explore the best-performing water systems across different population categories, from small towns to major metropolitan areas.
Larger cities often have more resources for advanced treatment facilities, but smaller communities may have cleaner source water. Both can achieve excellent water quality with proper management and investment.
Cities serving 500,000+ residents
| Rank | City | State | Score | Grade | Population |
|---|---|---|---|---|---|
| 1 | San Diego | California | 96/100 | A+ | 1,386,932 |
| 2 | Detroit | Michigan | 95/100 | A+ | 4,000,000 |
| 3 | Kansas City | Missouri | 95/100 | A+ | 630,000 |
| #4 | St Louis | Missouri | 95/100 | A+ | 1,100,000 |
| #5 | Charlotte | North Carolina | 95/100 | A+ | 1,100,000 |
| #6 | Omaha | Nebraska | 95/100 | A+ | 500,000 |
| #7 | Albuquerque | New Mexico | 95/100 | A+ | 680,000 |
| #8 | Las Vegas | Nevada | 95/100 | A+ | 2,300,000 |
| #9 | New York | New York | 95/100 | A+ | 9,800,000 |
| #10 | Rochester | New York | 95/100 | A+ | 540,000 |
Cities serving 100,000-500,000 residents
| Rank | City | State | Score | Grade | Population |
|---|---|---|---|---|---|
| 1 | Anaheim | California | 98/100 | A+ | 346,824 |
| 2 | Naperville | Illinois | 97/100 | A+ | 149,013 |
| 3 | Inglewood | California | 96/100 | A+ | 109,398 |
| #4 | Simi Valley | California | 96/100 | A+ | 126,181 |
| #5 | Lakeland | Florida | 96/100 | A+ | 112,641 |
| #6 | Peoria | Illinois | 96/100 | A+ | 113,150 |
| #7 | Lowell | Massachusetts | 96/100 | A+ | 115,554 |
| #8 | Montgomery | Alabama | 95/100 | A+ | 200,603 |
| #9 | Chandler | Arizona | 95/100 | A+ | 275,987 |
| #10 | Grand Rapids | Michigan | 95/100 | A+ | 300,000 |
Cities serving 50,000-100,000 residents
| Rank | City | State | Score | Grade | Population |
|---|---|---|---|---|---|
| 1 | Palm Desert | California | 97/100 | A+ | 51,988 |
| 2 | San Clemente | California | 97/100 | A+ | 65,040 |
| 3 | West Haven | Connecticut | 97/100 | A+ | 54,666 |
| #4 | Greenwood | Indiana | 97/100 | A+ | 63,830 |
| #5 | Hanford | California | 96/100 | A+ | 57,232 |
| #6 | Lodi | California | 96/100 | A+ | 67,539 |
| #7 | Monterey Park | California | 96/100 | A+ | 60,105 |
| #8 | Santa Barbara | California | 96/100 | A+ | 88,665 |
| #9 | Longmont | Colorado | 96/100 | A+ | 98,885 |
| #10 | Miami Beach | Florida | 96/100 | A+ | 92,307 |
Cities serving 10,000-50,000 residents
| Rank | City | State | Score | Grade | Population |
|---|---|---|---|---|---|
| 1 | Payson | Arizona | 98/100 | A+ | 15,929 |
| 2 | Romeoville | Illinois | 98/100 | A+ | 39,983 |
| 3 | Cumberland | Maryland | 98/100 | A+ | 19,495 |
| #4 | Pine Bluff | Arkansas | 97/100 | A+ | 41,253 |
| #5 | Salina | Kansas | 97/100 | A+ | 46,994 |
| #6 | Radcliff | Kentucky | 97/100 | A+ | 24,046 |
| #7 | Prichard | Alabama | 96/100 | A+ | 19,322 |
| #8 | Dunedin | Florida | 96/100 | A+ | 36,068 |
| #9 | Statesboro | Georgia | 96/100 | A+ | 33,438 |
| #10 | Mason City | Iowa | 96/100 | A+ | 27,338 |
Communities serving fewer than 10,000 residents
| Rank | City | State | Score | Grade | Population |
|---|---|---|---|---|---|
| 1 | El Paso | Texas | 97/100 | A+ | 1,821 |
| 2 | Portland | Oregon | 95/100 | A+ | 21 |
| 3 | Salem | Oregon | 95/100 | A+ | 30 |
| #4 | Erie | Pennsylvania | 95/100 | A+ | 380 |
| #5 | Memphis | Tennessee | 95/100 | A+ | 27 |
| #6 | Sitka | Alaska | 93/100 | A | 8,458 |
| #7 | Presque Isle | Maine | 89/100 | A- | 8,797 |
| #8 | Ketchikan | Alaska | 88/100 | A- | 8,192 |
| #9 | Vail | Colorado | 87/100 | A- | 5,305 |
| #10 | Elsmere | Delaware | 87/100 | A- | 5,814 |
Large metropolitan areas benefit from significant infrastructure investment and professional management. Many have upgraded to advanced treatment technologies and maintain extensive monitoring programs.
Mid-size cities often strike a balance between resources and complexity. Many have modernized systems while maintaining the agility to address issues quickly without bureaucratic delays.
Small communities frequently draw from pristine groundwater sources that require minimal treatment. Those with protected aquifers often have some of the purest tap water in the country.
City size alone does not determine water quality. What matters most is source water quality, treatment effectiveness, infrastructure maintenance, and regulatory compliance - factors that well-managed systems of any size can achieve.