Is Mahanalua Nui, HI Tap Water Safe to Drink?
Graded A+ with no contaminants above EPA limits. Here's everything we tested and how Mahanalua Nui ranks. What to do next ↓
97/100
waterverge.com Mahanalua Nui, HI — Water Quality Report
Mahanalua Nui's drinking water received a grade of A+ (97 out of 100), indicating excellent water quality. The city's 1 water system serves approximately 606 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 Mahanalua Nui's water
Mahanalua Nui ranks #11 out of 66 cities in Hawaii for water quality, placing it above average in the state.
Mahanalua Nui 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, Mahanalua Nui may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Mahanalua Nui has a clean compliance record with no violations on file, reflecting strong operational practices.
Water quality score
See methodology →Is Mahanalua Nui, HI water safe to drink?
Based on EPA testing data, Mahanalua Nui's tap water is generally safe to drink. The water system earned a grade of A+ (97/100), meeting federal drinking water standards across key contaminant categories. The city's 1 water system serves approximately 606 residents using groundwater (wells).
Recent water quality updates for Mahanalua Nui
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Mahanalua Nui's water quality assessment. Grade: A+ (97/100).
Federal disaster declaration (FEMA DR-4604). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-3529). Hurricane event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Mahanalua Nui's water supply.
Well within EPA limits.
Flood & environmental risk
Maui County has experienced 9 federally declared disasters since 1968. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies. Local water sources include Wailuku River At Kepaniwai Park, Maui, Wailuku River At Iao Valley Road, Maui, S Waiehu Str Us Of Ditch At Alt. 315 Ft, Maui, Waihee Rv Abv Waihee Dtch Intk Nr Waihee, Maui, Kahakuloa Stream Near Honokohau, Maui.
Where does Mahanalua Nui's water come from?
Mahanalua Nui's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 606 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 Kepaniwai Park, Maui (river), Wailuku River At Iao Valley Road, Maui (river), S Waiehu Str Us Of Ditch At Alt. 315 Ft, Maui (river), Waihee Rv Abv Waihee Dtch Intk Nr Waihee, Maui (river), Kahakuloa Stream Near Honokohau, Maui (river).
What Mahanalua Nui 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.
Mahanalua Nui's area has a history of flooding. After severe weather, watch for boil water advisories from your local utility.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violations & advisories
Flood & disaster history
Maui County has experienced 9 federally declared disasters since 1968. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
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 |
Lead level trend (90th percentile)
See how Mahanalua Nui compares by contaminant
Explore where Mahanalua Nui ranks among all Hawaii cities for specific contaminants.
Water source & infrastructure
Where Mahanalua Nui's water comes from
Mahanalua Nui'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 private ownership and serves approximately 606 people through 1 water system.
Water bodies near Mahanalua Nui
Mahanalua Nui is located near 5 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Mahanalua Nui
| System Name | PWSID | Population | Source |
|---|---|---|---|
| MAHANALUA NUI SUBDIVISON | HI0000251 | 606 | GW |
How Mahanalua Nui compares
Full Hawaii rankings →Mahanalua Nui's score of 97/100 is on par with the average of 92/100 among major Hawaii cities. It outscores 9 of 10 nearby cities.
Nearby cities
View Hawaii rankings →About Mahanalua Nui, HI
Wikipedia →Kahului is an unincorporated community and a census-designated place in Maui County in the U.S. state of Hawaii. It hosts the county's main airport, a deep-draft harbor, light industrial areas, and commercial shopping centers. The population was 28,219 at the 2020 census. Kahului is part of the Kahului-Wailuku-Lahaina Metropolitan Statistical Area which comprises all of Maui County, including nearby Wailuku and the West Maui town of Lahaina.
Learn more about your water
Guides and resources related to Mahanalua Nui's water quality findings.
Explore water quality across Maui
Frequently asked questions
Is Mahanalua Nui, HI tap water safe to drink?
Mahanalua Nui's water quality earned a grade of A+ (97/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #11 out of 66 cities tested in Hawaii.
What contaminants are in Mahanalua Nui's water?
Lead was measured at 0.0 ppb (90th percentile). No violations on record.
How is Mahanalua Nui'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 Mahanalua Nui?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Mahanalua Nui's water come from?
Mahanalua Nui's water is sourced from Groundwater. The city has 1 water system serving approximately 606 residents.
Is Mahanalua Nui's groundwater at risk of contamination?
Mahanalua Nui 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 Mahanalua Nui's water compare to other cities?
Mahanalua Nui ranks #11 out of 66 cities in Hawaii (better than 83% of state cities) and #116 out of 15744 cities nationally (99th percentile). The grade of A+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Mahanalua Nui's small water system affect quality?
Mahanalua Nui's system serves approximately 606 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.