Question 1

Is it safe to swim in Hawaii today?

Accepted Answer

It depends on the exact beach, current DOH advisories, recent rain, water color, posted signs, and ocean conditions. Hawaii's Department of Health monitors selected beaches for bacteria and issues advisories when results exceed recreational thresholds. Some shorelines have higher bacteria risk from streams, cesspools, harbors, and urban runoff, while dry open-ocean beaches are usually lower-risk. Check the live water-quality status for the specific beach before entering the water.

Question 2

What is a brown water advisory in Hawaii?

Accepted Answer

A brown water advisory is issued by the Hawaii Department of Health when heavy rain causes runoff that turns coastal waters brown. The discolored water can contain elevated levels of bacteria, chemicals, and debris from streets, farms, and cesspools. The DOH recommends staying out of the water for 48 to 72 hours after a brown water advisory is issued, even after the water appears to clear.

Question 3

Which Hawaii beaches have the worst water quality?

Accepted Answer

Beaches near stream mouths, harbors, canals, and cesspool-heavy watersheds tend to need the most caution. Examples include Kalapaki Beach/Nawiliwili Bay on Kauai, where the mapped Surfrider BWTF station has recorded repeated exceedances; Hanalei Bay near the river mouth, which has long-running impaired-water context; Hanakaoo Beach on Maui, which has recurring advisory history; and Kahalu'u Beach Park in Kona, where wastewater influence has been documented. Open-ocean leeward beaches such as Hapuna and Makena are usually lower-runoff choices, but they still need current-condition checks.

Question 4

Which Hawaiian island has the cleanest beaches?

Accepted Answer

The Big Island's Kohala Coast is usually one of Hawaii's lowest-runoff resort areas because it is dry, has few stream mouths, and has strong open-ocean circulation. Hapuna Beach, Mauna Kea Beach, and Mauna Lani are good examples of lower-bacteria-risk geography. On Maui, the Wailea-Makena coast is similarly lower-runoff than many windward or stream-adjacent areas. On Kauai, the south shore around Poipu is usually the lower-caution side, especially compared with rainier north and east shore stream mouths.

Question 5

Can you swim in Hawaii after it rains?

Accepted Answer

The Hawaii Department of Health recommends avoiding brown or murky water and often waiting at least 72 hours after heavy rain. Rain can move bacteria, sediment, trash, and chemicals from cesspools, roads, farms, streams, canals, and storm drains into the ocean. Some beaches recover faster than others: dry leeward beaches with no stream mouths, such as Ko Olina, Wailea, and Hapuna, are usually less affected than windward or stream-adjacent beaches such as Kailua, Hanalei Bay, or Waikiki near the Ala Wai Canal.

Question 6

Are Hawaii beaches tested for bacteria?

Accepted Answer

The Hawaii DOH Clean Water Branch tests about 57 beaches statewide, a fraction of the 300+ swimmable beaches across the islands. Surfrider Foundation supplements this with volunteer testing at additional sites. Many popular beaches have no regular testing at all. This site aggregates data from DOH, Surfrider, USGS stream monitoring (25 stations), NOAA ocean conditions, and city-level testing to provide broader coverage than any single source.

Question 7

What does a beach advisory mean in Hawaii?

Accepted Answer

Hawaii issues three types of water quality advisories. A brown water advisory means rain runoff has discolored coastal waters — these are the most common and affect wide areas after storms. A beach advisory means DOH tested a specific beach and found bacteria (enterococci) above 130 CFU per 100mL, the EPA threshold. A sewage spill notification means a confirmed wastewater discharge has reached or may reach the ocean. Brown water advisories clear when rain stops. Bacteria advisories require follow-up testing to confirm levels have dropped.

Question 8

Is Waikiki Beach water clean?

Accepted Answer

Waikiki Beach water quality varies by location and weather. The central beach area generally passes weekly bacteria tests. However, the Ala Wai Canal — a 75-acre drainage canal that collects runoff from a 19-square-mile watershed — empties near the west end of Waikiki. After rain, bacteria levels near the canal can spike significantly. The east end of Waikiki near Diamond Head and the Duke Kahanamoku Beach area tend to have better water quality than the sections closest to the Ala Wai.

Hawaii Beach Water Quality Today