Hawaii Water Fluoride: Updated Statistics

Hawaii has long stood out in national comparisons of water fluoridation, with some of the lowest fluoridation rates in the United States. This article compiles key data points and trends from the past two decades to provide a clear statistical overview of how limited fluoridation continues to impact oral health statewide.

While most U.S. states maintain higher coverage rates, Hawaii’s unique geographical and political landscape has contributed to consistently low levels of community water fluoridation. Below, we examine core statistics regarding coverage, tooth decay prevalence, costs, and regional comparisons, presenting the data in a concise format for ease of reference.

Key Statistics Snapshot

Here are a few immediate figures that illuminate Hawaii’s fluoridation status and oral health challenges:

• 8.5% of Hawaii residents served by community water systems receive fluoridated water.
• 70.6% of third graders in Hawaii experience tooth decay—the highest rate in the nation.
• 47% of Hawaiian adults have lost at least one tooth due to decay.
• Hawaii’s Medicaid dental costs for children exceed $12 million annually.

These numbers provide only a glimpse. Further sections break down additional data on fluoride coverage, oral health impacts, and comparative state statistics, offering a broad foundation for understanding this issue.

Historical and Current Coverage Levels

Data on fluoridation coverage in Hawaii highlight a longstanding pattern of minimal adoption across community water systems.

• As of 2025, 8.5% of the population served by community water systems receives fluoridated water.
• This coverage percentage has remained stagnant since at least 2020, showing no measurable increase.
• In contrast, the average U.S. fluoridation rate is approximately 72.3%.
• Military installations (federal systems) make up nearly all fluoridated sources in Hawaii, serving 11.7% of residents.

Coverage data underscores how Hawaii’s overall fluoridation rates lag well behind other states. The table below illustrates Hawaii’s coverage trends over selected years, reflecting minimal movement despite national norms.

Although external factors like geology and a decentralized water system pose challenges, the consistency of these figures is notable when viewed alongside rising oral health costs.

Oral Health Impacts

Hawaii’s low fluoridation rates coincide with pronounced issues in oral health among both children and adults.

• 70.6% of third graders in Hawaii experience tooth decay, the highest third-grade rate in the nation.
• Among low-income Head Start children aged 3–5, 61% have untreated cavities.
• 47% of adults in Hawaii have lost at least one tooth to decay.
• Research suggests states with higher fluoridation see up to 30% lower decay rates in children overall.

Tooth decay disparities extend across multiple demographics in the islands. Studies estimate a potential 25% reduction in childhood caries if fluoride were widely adopted, confirming a pattern observed nationwide.

This pattern of extensive decay and tooth loss significantly increases the social and financial burdens on communities, as shown in the next section on costs.

Cost and Resource Implications

The financial toll of inadequate fluoridation can be observed in treatment costs, emergency room visits, and disparities in how preventive care is delivered.

• Hawaii’s annual Medicaid dental costs for children exceed $12 million.
• Emergency room visits for preventable dental conditions rose by 22% since 2015.
• Non-fluoridated communities rely on topical fluoride treatments that cost around $55 per child annually.
• By comparison, community water fluoridation can cost as little as $0.50 per person each year.

High treatment expenses, combined with the need for intensive restorative care, disproportionately affect vulnerable populations. The following table highlights approximate cost disparities and usage patterns.

This cost discrepancy and higher incidence of tooth decay illustrate why so many compare Hawaii’s outcomes to states with broader fluoridation coverage.

Regional Fluoridation Comparisons

Data from Western states offers an important benchmark for Hawaii’s comparatively low coverage rates and higher rates of decay.

• California mandates fluoridation in large water systems, reaching 92.0% coverage.
• Washington reports 63.0% coverage.
• Oregon, requiring local voter approval, stands at 33.0% coverage.
• Nevada’s municipal initiatives reach 47.0% coverage.

Hawaii’s 8.5% rate is markedly lower than all of these. The table below demonstrates how these coverage levels correlate with third-grade decay rates.

While economic and demographic factors also play a role, the stark contrast in coverage and decay rates remains noteworthy in regional comparisons.

Key Statistics Summary

Below are several of the most critical data points from this article:

• Only 8.5% of Hawaii’s community water system users receive fluoridated water.
• 70.6% of third graders in Hawaii have tooth decay, the nation’s highest rate.
• 61% of low-income Head Start children have untreated cavities.
• Annual Medicaid dental costs for children in Hawaii exceed $12 million.

Across multiple age groups, Hawaii shows consistently higher tooth decay rates compared to more fully fluoridated states. Although other factors contribute to oral health outcomes, the data suggest fluoridation coverage remains a key metric affecting dental health trends statewide.