State Well Water Guide
Hawaii Private Well Water Guide
About 18% of Hawaiians use private wells, primarily on the Big Island's rural communities, parts of Maui and Oahu outside municipal service areas, and agricultural properties. Hawaii's unique volcanic geology creates a distinctive groundwater picture: the primary aquifer systems are young basaltic lava flows that act as highly permeable conduits. Agricultural contamination from former sugar and pineapple plantations — particularly DBCP (dibromochloropropane) and EDB (ethylene dibromide) from pineapple production — is a legacy contamination issue. Naturally elevated iron and manganese in basalt aquifers, and PFAS from Pearl Harbor/Hickam AFB, are additional concerns. DOH regulates well construction.
Testing Guidance
Hawaii DOH recommends annual testing for coliform bacteria and nitrates. All well owners should test for DBCP and EDB given Hawaii's history of pineapple production and the pesticides' widespread use. Oahu and Maui well owners should test for PFAS given Pearl Harbor/Hickam and other military installations. Big Island volcanic area well owners should test for iron, manganese, and pH from fresh basalt leaching.
What to Test For in Hawaii
Total coliform bacteria and E. coli — annual minimum
DBCP and EDB — legacy agricultural pesticides from pineapple and sugarcane production; widespread in Hawaii aquifers
PFAS — near Pearl Harbor/Joint Base Pearl Harbor-Hickam, Kaneohe Marine Corps Air Station, and Schofield Barracks
Nitrates — agricultural areas, particularly former pineapple and sugarcane lands
Iron and manganese — basalt aquifer wells, especially on the Big Island
Volatile organic compounds — near military and industrial sites
pH — fresh basalt rock can make water slightly acidic
Common Contamination Risks in Hawaii
DBCP and EDB pesticide contamination — Hawaii's pineapple and sugarcane industries used these pesticides heavily before their banning in the 1970s-1980s; both remain in Hawaii groundwater decades later and are human carcinogens
PFAS from military installations — Pearl Harbor/Hickam, Kaneohe MCAS, Barber's Point, and other installations have significant PFAS contamination histories
Agricultural chemical contamination — Hawaii's intensive tropical agriculture has used numerous pesticides that persist in the basaltic aquifer system
Iron and manganese from fresh basalt — young volcanic rocks on the Big Island can leach metals into groundwater
Bacterial contamination from agricultural runoff — Hawaii's warm, wet climate accelerates bacterial growth
Contaminant Guides Relevant to HI Wells
PFAS
Synthetic Chemicals
EPA limit: 4 ppt
Lead
Heavy Metals
EPA limit: 15 ppb (action level)
Nitrates
Agricultural Chemicals
EPA limit: 10 mg/L
DBPs
Disinfection Byproducts
EPA limit: 80 µg/L (TTHMs) / 60 µg/L (HAA5)
Arsenic
Heavy Metals
EPA limit: 10 ppb
Hard Water
Minerals
EPA limit: No federal limit
Chlorine
Disinfection Chemicals
EPA limit: 4 mg/L (MRDL)
Microplastics
Emerging Contaminants
EPA limit: No federal limit
Bacteria
Microbial Contamination
EPA limit: Zero E. coli / < 1 coliform per 100 mL
Fluoride
Minerals
EPA limit: 4 mg/L (MCL) / 2 mg/L (Secondary MCL)
Chromium-6
Heavy Metals
EPA limit: 100 ppb (total chromium)
Copper
Heavy Metals
EPA limit: 1.3 mg/L (action level)
Radon
Radioactive Contaminants
EPA limit: No finalized MCL
Iron & Manganese
Minerals
EPA limit: 0.3 mg/L iron / 0.05 mg/L manganese (aesthetic SMCLs)
Atrazine
Agricultural Chemicals
EPA limit: 3 ppb (0.003 mg/L)
Uranium
Radioactive Contaminants
EPA limit: 30 µg/L (30 ppb)
Perchlorate
Industrial Chemicals
EPA limit: 0.056 mg/L (56 ppb)
VOCs
Industrial Chemicals
EPA limit: Varies by compound: benzene 5 ppb; TCE 5 ppb; PCE 5 ppb; vinyl chloride 2 ppb
Radium
Radioactive Contaminants
EPA limit: 5 pCi/L (combined Ra-226 + Ra-228)
Crypto & Giardia
Microbial Contamination
EPA limit: Zero (treatment technique standard)
Hydrogen Sulfide
Naturally Occurring Compounds
EPA limit: No MCL; Secondary MCL (aesthetic) of 0.05 mg/L
Selenium
Minerals
EPA limit: 50 ppb (0.05 mg/L)
Cadmium
Heavy Metals
EPA limit: 5 ppb (0.005 mg/L)
Mercury
Heavy Metals
EPA limit: 2 ppb (0.002 mg/L)
Barium
Heavy Metals
EPA limit: 2 mg/L
Find a Certified Lab in Hawaii
Use the Hawaii state-certified laboratory program to find accredited labs for private well testing. Always verify current certification before submitting samples.
HI Certified Lab Directory ↗Hawaii Well Water FAQs
Related Pages
Data Sources & Provenance
All data on this page is sourced from official U.S. government or public datasets.
Quick Reference
State program
HI Certified Labs ↗EPA guidance
EPA Private Wells Program ↗State lab directory
HI Certified Labs ↗Minimum Annual Tests
Plus state-specific contaminants listed above
Other State Guides