# Safe to Swim Hawaii

> Safe to Swim Hawaii is the most comprehensive real-time beach water quality tracker for the Hawaiian Islands. The site aggregates live data from 6 government agencies and research institutions to help visitors and residents check ocean conditions before swimming. It answers "Is the water clean?" — covering bacteria, sewage spills, brown water runoff, and stream contamination — not surf conditions or drowning risk.

The site monitors all six main Hawaiian islands (O'ahu, Maui, Kaua'i, Hawai'i/Big Island, Moloka'i, Lana'i) with 485+ beach and guide pages.

## Live Data Sources

- **Hawaii DOH Clean Water Branch** — Brown Water Advisories, Beach Advisories (bacteria exceedances), and Sewage Spill notifications. Checked every 15 minutes via CSV API.
- **USGS National Water Information System** — 25 stream gauging stations across all islands (O'ahu 11, Kaua'i 7, Maui 3, Big Island 3, Moloka'i 1) monitoring discharge, stage height, and turbidity (4 O'ahu stations). 1-year daily median baselines for anomaly detection.
- **NOAA CO-OPS** — 5 tide stations providing water level and sea temperature (Honolulu, Kahului, Nawiliwili, Hilo, Mokuoloe)
- **NDBC (National Data Buoy Center)** — 5 wave buoys providing significant wave height data
- **NWS Honolulu** — Active weather alerts for all Hawaiian islands
- **City & County of Honolulu ENV** — Kailua Bay bacteria testing (7 monitoring stations, updated ~5x/month) and wastewater spill notifications via WordPress REST API

## Live API

All data is available as JSON from a single endpoint:
`https://safetoswimhawaii.com/.netlify/functions/api`

Returns: active advisories, recent (cleared) advisories, USGS stream conditions with anomaly flags, NOAA ocean conditions, NWS weather alerts, and city monitoring data.

## Safety Guides

- [Swimming After Rain — The 72-Hour Rule](https://safetoswimhawaii.com/swimming-after-rain/): Bacteria spikes 500% after heavy rain. Which beaches recover fastest and why.
- [Brown Water Advisory Guide](https://safetoswimhawaii.com/brown-water-advisory/): What brown water means, when it clears, and which beaches are most affected.
- [Jellyfish Calendar 2026](https://safetoswimhawaii.com/jellyfish-calendar/): Box jellyfish warning dates based on the lunar cycle. South shore O'ahu most affected.
- [Hawaii Water Quality Today](https://safetoswimhawaii.com/hawaii-water-quality-today/): Live statewide advisory dashboard.
- [Best Time to Swim in Hawaii](https://safetoswimhawaii.com/best-time-to-swim-hawaii/): Seasonal water quality — dry season (May-Sep) vs wet season (Oct-Apr).
- [Leptospirosis & Freshwater Safety](https://safetoswimhawaii.com/leptospirosis-hawaii/): Freshwater swimming risks — streams, waterfalls, and rivers.
- [Hawaii Beach Bacteria Guide](https://safetoswimhawaii.com/hawaii-beach-bacteria-guide/): How bacteria testing works, what enterococci means, and EPA thresholds.
- [Sewage Spill Guide](https://safetoswimhawaii.com/hawaii-sewage-spill-guide/): How Hawaii's 83,000 cesspools affect ocean water quality.

## Island Pages

- [O'ahu Water Quality Today](https://safetoswimhawaii.com/oahu/): Live advisories and 50+ beach pages
- [Maui Water Quality Today](https://safetoswimhawaii.com/maui/): Live advisories and 40+ beach pages
- [Kaua'i Water Quality Today](https://safetoswimhawaii.com/kauai/): Live advisories and 30+ beach pages
- [Big Island Water Quality Today](https://safetoswimhawaii.com/big-island/): Live advisories and 30+ beach pages

## Top Beach Pages (by traffic)

- [Waikiki Beach](https://safetoswimhawaii.com/waikiki-beach/): O'ahu, bacteria risk 2/5, Ala Wai Canal contamination risk
- [Hanauma Bay](https://safetoswimhawaii.com/hanauma-bay/): O'ahu, protected marine preserve, risk 1/5
- [Ko Olina Lagoons](https://safetoswimhawaii.com/ko-olina-lagoons/): O'ahu west side, 88% zero bacteria (UH study), risk 1/5
- [Kailua Beach](https://safetoswimhawaii.com/kailua-beach/): O'ahu windward, risk 2/5
- [Lanikai Beach](https://safetoswimhawaii.com/lanikai-beach/): O'ahu, risk 2/5
- [Ka'anapali Beach](https://safetoswimhawaii.com/kanapali-beach/): West Maui, risk 3/5
- [Hapuna Beach](https://safetoswimhawaii.com/hapuna-beach/): Big Island Kohala Coast, consistently cleanest statewide, risk 1/5
- [Poipu Beach](https://safetoswimhawaii.com/poipu-beach/): Kaua'i south shore, risk 2/5
- [Hanalei Bay](https://safetoswimhawaii.com/hanalei-bay/): Kaua'i, DOH-impaired since 2004, 360+ cesspools, risk 4/5
- [Wailea Beach](https://safetoswimhawaii.com/wailea-beach/): South Maui, risk 2/5
- [Sandy Beach](https://safetoswimhawaii.com/sandy-beach/): O'ahu east side, dangerous shorebreak, risk 2/5
- [Sunset Beach](https://safetoswimhawaii.com/sunset-beach/): O'ahu North Shore, risk 2/5
- [Waimea Bay](https://safetoswimhawaii.com/waimea-bay/): O'ahu North Shore, river mouth, risk 3/5
- [Makena Beach](https://safetoswimhawaii.com/makena-beach/): South Maui, risk 1/5
- [Kahalu'u Beach Park](https://safetoswimhawaii.com/kahaluu-beach/): Big Island Kona, 92% bacteria failure rate, risk 3/5

## Important Context

- Hawaii has 83,000 cesspools discharging 52 million gallons/day of untreated sewage near coastal waters
- DOH only monitors 57 of 300+ recreational beaches weekly — most beaches have zero regular testing
- Surfrider Foundation 2024 data found 80% of tested Hawaii beaches exceeded EPA health limits at least once
- Bacteria risk ratings use a 1-5 scale: 1=Low, 2=Moderate-Low, 3=Moderate, 4=Elevated, 5=High
- The EPA standard for enterococci in recreational water is 130 CFU/100mL (Beach Action Value)
- "No advisory posted" does NOT mean the water was tested and found clean — it often means nobody tested
- This site provides information only and is not affiliated with any government agency