We found 25 public water systems in Niagara county (ordered by population size).
| Name | Areas served | Population served | Contaminant count | Violation count |
|---|---|---|---|---|
| Niagara Falls Water Board | Niagara Falls | 50,193 | 26 | 28 |
| North Tonawanda City | North Tonawanda | 31,568 | 31 | 0 |
| Lockport City Wtp | Lockport | 21,165 | 30 | 0 |
| Lockport Wd#3 | Lockport | 20,529 | 30 | 0 |
| Wheatfield Wd | Wheatfield | 18,117 | 32 | 0 |
| Lewiston Water Improvementarea | Lewiston | 16,257 | 31 | 0 |
| Niagara Water Improvement Area | Niagara, Niagara Falls | 8,400 | 0 | 0 |
| Royalton Townwide Water Dist. | Royalton | 7,710 | 0 | 0 |
| Porter Master Improvement Area | Porter, Youngstown | 6,920 | 0 | 0 |
| Newfane Wd#4 | Newfane | 6,180 | 0 | 1 |
| Pendleton Town Wd | Pendleton | 6,050 | 0 | 0 |
| Wilson Town Water District | Wilson | 5,993 | 0 | 0 |
| Cambria Water District | Cambria | 5,400 | 0 | 0 |
| Hartland Wd | Hartland, Royalton | 4,117 | 0 | 0 |
| Newfane Wd No1,2,3 Consol | Newfane | 3,477 | 0 | 1 |
| Lewiston Village | Lewiston | 2,781 | 0 | 0 |
| Somerset Consolidated Wd | Somerset | 2,723 | 0 | 0 |
| YOUNGSTOWN (V) | Youngstown | 2,021 | 0 | 0 |
| Middleport Village | Middleport | 1,917 | 0 | 33 |
| Wilson Village | Wilson | 1,213 | 0 | 0 |
| Barker Village | Barker | 577 | 0 | 0 |
| Carlisle Gardens Lockport Wd#1 | Lockport | 323 | 0 | 0 |
| Lincoln Village Lockport Wd#2 | Lockport | 253 | 0 | 0 |
| Tuscarora Indian School | County of Niagara | 20 | 0 | 0 |
| Niagara County Water District | County of Niagara | 0 | 0 | 0 |