Water Quality: Honolulu, HI
15 water systems • 961,760 people served
Some ConcernsWater Quality Summary
Honolulu is served by 15 public water systems with a combined service population of 961,760 people, and has 13 EPA Safe Drinking Water Act violations on record. Critically, 1 of those are health-based violation, meaning one or more contaminants were detected above EPA-established safe levels — a serious public health concern. Honolulu's violation count is 129% above the national average for Hawaii. Contaminants associated with violations include E. coli.
Contaminants Found
Causes gastrointestinal illness; certain strains (e.g., O157:H7) can cause severe kidney failure and death.
Common source: Fecal contamination from humans or animals entering the water supply
EPA limit: Zero (no E. coli permitted in drinking water)
Water Systems Serving Honolulu
| System Name | PWSID | Source | Population | Violations |
|---|---|---|---|---|
| HNL-WINDWARD-PEARL HARBOR | HI0000331 | Groundwater | 631,389 | 0 |
| WAIPAHU-EWA-WAIANAE | HI0000335 | Groundwater | 217,479 | 0 |
| MILILANI | HI0000367 | Groundwater | 50,573 | 0 |
| WAHIAWA | HI0000333 | Groundwater | 23,348 | 0 |
| WAIPIO HEIGHTS | HI0000334 | Groundwater | 11,516 | 0 |
| WAIALUA-HALEIWA | HI0000332 | Groundwater | 9,996 | 0 |
| WAIALEE-SUNSET BEACH | HI0000366 | Groundwater | 4,916 | 0 |
| KAMEHAMEHA SCHOOLS | HI0000319 | Groundwater | 4,000 | 0 |
| THE QUEEN'S MEDICAL CENTER | HI0000312 | Groundwater | 3,440 | 6 |
| KAHUKU | HI0000365 | Groundwater | 2,730 | 1 |
| DILLINGHAM AIRFIELD | HI0000338 | Groundwater | 1,800 | 0 |
| WAIAHOLE | HI0000368 | Groundwater | 300 | 2 |
| PUNALU'U | HI0000114 | Groundwater | 200 | 1 |
| WOODLANDS AT NUUANU | HI0000372 | Groundwater | 48 | 0 |
| POAMOHO | HI0000371 | Groundwater | 25 | 3 |
Concerned About Your Water?
A home water filter can remove common contaminants. NSF-certified filters are tested against EPA standards.
Consider a reverse osmosis system for comprehensive filtration or a carbon filter for basic improvement.
Other Cities in Hawaii
Data Sources
Drinking water violation data from the EPA Safe Drinking Water Information System (SDWIS). Data includes all recorded violations for active community water systems.