Is Honomu, HI Tap Water Safe to Drink?
Graded A — but Copper was detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
93/100
waterverge.com Honomu, HI — Water Quality Report
Honomu's drinking water received a grade of A (93 out of 100), indicating excellent water quality. The city's 1 water system serves approximately 645 residents using groundwater.
Lead levels were measured at 0.0 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
No violations are on record for this water system.
What to know about Honomu's water
Honomu ranks #31 out of 66 cities in Hawaii for water quality, placing it mid-range in the state.
Honomu relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff.
As a small community water system, Honomu may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Honomu has a clean compliance record with no violations on file, reflecting strong operational practices.
Water quality score
See methodology →Is Honomu, HI water safe to drink?
Based on EPA testing data, Honomu's tap water is generally safe to drink. The water system earned a grade of A (93/100), meeting federal drinking water standards across key contaminant categories. The city's 1 water system serves approximately 645 residents using groundwater (wells).
Recent water quality updates for Honomu
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Honomu's water quality assessment. Grade: A (93/100).
Key contaminant findings
Based on the most recent EPA sampling data for Honomu's water supply.
Well within EPA limits.
Exceeds EPA action level. Copper can leach from household plumbing — flush taps for 30 seconds before drinking.
Where does Honomu's water come from?
Honomu's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 645 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Wailuku River At Piihonua (river), Honolii Stream Nr Papaikou (river).
What Honomu residents can do
Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violations & advisories
Recommended water filters
Based on contaminants detected in Honomu's water supply, we recommend the following filter types.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 0.0 | 15 | ppb | Inorganic | Safe |
| Copper (90th percentile) CopperInorganic A metal that enters drinking water mainly through corrosion of copper plumbing. Small amounts are essential for health, but excess levels are harmful. Health EffectsGastrointestinal distress (nausea, vomiting, diarrhea) at short-term high levels; liver and kidney damage from long-term exposure. EPA Limit1.3 mg/L action level Common SourcesCorrosion of copper household plumbing, erosion of natural deposits. | 1.70 | 1.3 | mg/L | Inorganic | Over Limit |
Lead level trend (90th percentile)
Copper level trend (90th percentile)
See how Honomu compares by contaminant
Explore where Honomu ranks among all Hawaii cities for specific contaminants.
Water source & infrastructure
Where Honomu's water comes from
Honomu's drinking water is drawn from underground aquifers through wells.
Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals.
Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds.
The system is operated by local government ownership and serves approximately 645 people through 1 water system.
Water bodies near Honomu
Honomu is located near 2 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Honomu
| System Name | PWSID | Population | Source |
|---|---|---|---|
| HONOMU | HI0000105 | 645 | GW |
How Honomu compares
Full Hawaii rankings →Honomu's score of 93/100 is on par with the average of 92/100 among major Hawaii cities. It outscores 7 of 10 nearby cities.
Nearby cities
View Hawaii rankings →About Honomu, HI
Wikipedia →Hilo is the largest settlement in and the county seat of Hawaiʻi County, Hawaii, United States, which encompasses the Island of Hawaiʻi, and is a census-designated place (CDP). The population was 44,186 according to the 2020 census. It is the fourth-largest settlement in the state of Hawaiʻi, the largest settlement in the state outside of Oahu, and the largest settlement in the state outside of the Greater Honolulu Area.
Learn more about your water
Guides and resources related to Honomu's water quality findings.
Explore water quality across Hawaii
Frequently asked questions
Is Honomu, HI tap water safe to drink?
Honomu's water quality earned a grade of A (93/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #31 out of 66 cities tested in Hawaii.
What contaminants are in Honomu's water?
Lead was measured at 0.0 ppb (90th percentile). No violations on record.
How is Honomu's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Honomu?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Honomu's water come from?
Honomu's water is sourced from Groundwater. The city has 1 water system serving approximately 645 residents.
Is Honomu's groundwater at risk of contamination?
Honomu uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. Current testing shows the groundwater meets EPA standards. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.
How does Honomu's water compare to other cities?
Honomu ranks #31 out of 66 cities in Hawaii (better than 53% of state cities) and #1040 out of 15744 cities nationally (93th percentile). The grade of A reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Honomu's small water system affect quality?
Honomu's system serves approximately 645 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has maintained a clean compliance record.