Backflow Laws: Hawaii
Hawaii Backflow Prevention Laws, Regulations, and Compliance Requirements
Hawaii's backflow prevention requirements are governed by Hawaii Administrative Rules Title 11, Chapter 21 — Backflow and Cross-Connection Control — administered by the Hawaii State Department of Health (DOH). Hawaii is unique nationally in operating as an island state with county-level water systems and PAMCA-based tester training. This guide covers Hawaii DOH regulations, the Honolulu Board of Water Supply's program (the largest in the state), and the County of Hawaii Department of Water Supply requirements.
Hawaii State Regulatory Framework
Hawaii’s backflow prevention requirements are established in Hawaii Administrative Rules (HAR) Title 11, Chapter 21 — Backflow and Cross-Connection Control — administered by the Hawaii State Department of Health (DOH) Safe Drinking Water Branch. Additional governing rules are found in HAR Title 11, Chapter 20 (Public Water Systems). Hawaii holds EPA primacy under the federal Safe Drinking Water Act.
Hawaii DOH requires all community water systems to implement cross-connection control programs aligned with Chapter 21 standards. All major water purveyors in the state are required to implement annual backflow prevention assembly (BFPA) testing programs affecting agricultural, commercial, industrial water users and high-rise and multi-family residential developments.
Hawaii's County-Based Water System Structure
Unlike most U.S. states where municipalities or water districts serve specific areas within a broader state program, Hawaii’s four counties each have county-level water systems or departments as the primary water purveyors. The City and County of Honolulu (Oahu) is served by the Board of Water Supply (BWS). The County of Hawaii (Big Island) is served by the Department of Water Supply (DWS). Maui County and Kauai County each have their own county water departments. All operate under Hawaii DOH Chapter 21 requirements.
Tester Certification in Hawaii
Hawaii has a distinctive tester certification structure built around the Plumbing and Mechanical Contractors Association of Hawaii (PAMCA), Local 675. BWS has historically offered tester training in coordination with PAMCA; however, BWS suspended offering its own tester training course as of 2024. Current tester training and certification is obtained through the PAMCA Training Workshop at (808) 456-0585.
Each tester must obtain a Certificate of Competence from either PAMCA, USC-FCCCHR (University of Southern California Foundation for Cross-Connection Control and Hydraulic Research), or the California-Nevada Section of AWWA (CA-NV AWWA). Certification is valid for three years. Recertification after three years can be obtained through ABPA (American Backflow Prevention Association) re-certification. For Oahu: testers must be on BWS’s approved list to file results with BWS.
Hawaii's PAMCA-Centered Training Is Unique Nationally
Most U.S. states accept ASSE 5110 or ABPA as the primary tester credentials. Hawaii built its tester training program around PAMCA Local 675’s training facility, which was modeled after USC-FCCCHR. With BWS suspending its own training offerings in 2024, new testers must go through PAMCA workshops at (808) 456-0585 or through USC-FCCCHR/CA-NV AWWA directly. This local training structure makes Hawaii’s certification pathway distinct from mainland standards.
Major Water Purveyors in Hawaii
Board of Water Supply (BWS) — Honolulu, Oahu
The Honolulu Board of Water Supply (BWS) is Hawaii’s largest water utility, serving approximately 400,000 accounts across Oahu. BWS established its cross-connection control program in the early 1970s and operates one of the most comprehensive programs in the state. The program is administered by the BWS Cross-Connection Control Section (CCCS), managing and overseeing over 9,000 private- and government-owned backflow prevention assemblies across the island. CCCS can be reached at (808) 748-5470, cccs@hbws.org.
BWS’s testing program operates under BWS Rules and Regulations Section 2-213, Cross-Connection Control and Backflow Prevention, and Hawaii DOH Title 11, Chapter 21. Annual testing is required for all covered assemblies. Upon installation, a certified tester fills out a Backflow Prevention Installation and Test form (provided during building permit processing). After testing, the assembly owner must sign the form, keep a copy, and mail, fax, or email the completed form to BWS CCCS.
BWS requires that assemblies be approved and listed by USC-FCCCHR. Their Approved List of Reduced Pressure Backflow Prevention Assemblies (updated March 4, 2024) is available from BWS. All assemblies must be installed above ground and in locations safe from flooding or submergence, unless BWS approves an exception in writing.
Facilities requiring BWS backflow assemblies include commercial, manufacturing, and industrial developments; medical facilities; hotels; high-rise buildings; shopping centers; schools; parks; golf courses; farms; potable and non-potable irrigation systems; make-up lines to chill water/condenser water air conditioning systems; booster pumps; trap primers; water features; swimming pool recirculation systems; boilers; and chemical injection systems.
County of Hawaii Department of Water Supply (DWS)
The County of Hawaii (Big Island) Department of Water Supply administers backflow prevention requirements under Hawaii DOH Chapter 21 and the DWS Rules and Regulations. The DWS requires backflow prevention assemblies for all agricultural activities; properties with auxiliary water sources (reclaimed water, swimming pools, catchment tanks, ponds); and residential facilities with any potential hazard (irrigation with chemical injection, auxiliary water supplies, industrial equipment). Annual testing is required. All installations must be approved by DWS’s Cross-Connection Control Section at (808) 961-8670.
Maui County and Kauai County Water Systems
Maui County’s Department of Water Supply and Kauai County’s Department of Water serve their respective islands. Both operate under Hawaii DOH Chapter 21 requirements. Agricultural users are a significant category for backflow compliance on both islands — all farms connected to a public water system in any way must have an approved, maintained, and annually tested backflow preventer. Property owners on Maui and Kauai should confirm program requirements directly with their county water department.
Agricultural Users Are Not Exempt in Hawaii
A common misconception in Hawaii is that agricultural water customers receiving agricultural rates are exempt from backflow prevention requirements. This is incorrect. All farms in Hawaii connected to a public water system in any way are required to have an approved, maintained, and annually tested backflow preventer, regardless of their rate category. The installation of a backflow prevention assembly does not automatically constitute approval for agricultural rates — the two issues are entirely separate. Confirm with your county water department what assembly type is required for your agricultural use.
Property Owner Compliance Summary for Hawaii
Installation: Install a USC-FCCCHR approved assembly above ground. Any connections to auxiliary water sources, agricultural uses, or high-hazard facilities require an RPZ. Coordinate with your county water system’s Cross-Connection Control Section before installation.
Testing: Annual testing by a tester with a Certificate of Competence from PAMCA, USC-FCCCHR, or CA-NV AWWA. Tester must be on BWS’s approved list for Oahu properties.
Filing: Complete the Installation and Test form, sign as assembly owner, and submit to BWS CCCS (Oahu) or the appropriate county DWS.
Farms: All Hawaii farms on public water must have approved, maintained, annually tested backflow preventers.
Records: Retain all test reports and maintenance records.
Find a Certified Backflow Tester in Hawaii
For Oahu properties, contact BWS CCCS at (808) 748-5470 or cccs@hbws.org for the current approved tester list. For Big Island, contact DWS at (808) 961-8670. New tester certification: contact PAMCA Training Workshop at (808) 456-0585. Visit getyourbackflowtested.com/backflow-testing-near-me/hawaii-backflow-testing for the directory.
Hawaii Regulatory Reference Links
| Resource / Agency | URL / Link Target |
|---|---|
Hawaii DOH Safe Drinking Water Branch | |
HAR Title 11, Chapter 21 — Backflow and Cross-Connection Control | |
BWS — Cross-Connection Control | |
BWS — Testing Program | |
BWS — Chapter II (Cross-Connection Rules) | |
County of Hawaii DWS — Backflow Prevention | |
PAMCA Training Workshop — (808) 456-0585 | |
UH CTAHR — Backflow Prevention for Farms in Hawaii |