Hawaii has four different types of swim advisories, and they mean very different things. A Beach Advisory is not the same as a Brown Water Advisory. A Sewage Spill is not the same as a Permit Exceedance. This guide explains each one, what the bacteria numbers actually mean, and the biggest misconception of all — that no advisory means the water was tested and found clean.
All swim advisories in Hawaii are issued by the Hawaii Department of Health (DOH) Clean Water Branch (CWB). They are the state agency responsible for monitoring recreational water quality. Each advisory type has a different trigger, different meaning, and different duration.
What triggers it: A water sample collected at a specific beach exceeds the enterococci bacteria threshold of 130 CFU per 100 milliliters. The DOH collects these samples at approximately 57 beaches across the state on a roughly weekly schedule.
What it means: The bacteria level in the tested sample was high enough to pose an elevated risk of illness to swimmers. This is based on a single sample, not an average — Hawaii uses the EPA’s Statistical Threshold Value (STV) for single-sample assessments. Common sources include sewage from cesspools, animal waste, and stormwater runoff.
How long it lasts: The advisory remains in effect until a follow-up sample tests below the threshold. This typically takes 3–7 days, but chronically impaired beaches (like Kalapaki Beach on Kauaʻi) can have advisories that last weeks or recur immediately after being lifted.
What you should do: Avoid swimming at that specific beach until the advisory is lifted. Note that the advisory applies to the tested location only — a beach 500 meters away may have completely different conditions, though contamination often affects a broader area than the single test point.
What triggers it: Heavy rainfall causes visible brown-colored runoff to flow into coastal waters through streams, rivers, and storm drains. The DOH issues these based on rainfall reports, visual confirmation, and reports from the public. These are often island-wide or cover large coastal areas.
What it means: Stormwater has washed sediment, bacteria, chemicals, and debris from land into the ocean. The brown color you see is primarily dirt and sediment, but it carries invisible contaminants including fecal bacteria from Hawaii’s roughly 88,000 cesspools, animal waste, pesticides, fertilizers, and urban pollution. Brown water advisories are the most common type of advisory in Hawaii, especially during the wet season (November–March).
How long it lasts: Typically 2–5 days after rain stops, depending on rainfall intensity and how quickly the runoff clears. The DOH lifts the advisory based on visual assessment and reports from field staff. Importantly, the DOH pauses bacteria testing during brown water advisories because high sediment loads make lab analysis unreliable. This creates an information gap during the highest-risk period.
What you should do: Stay out of the water at all affected beaches. Follow the 72-hour rule — wait at least 72 hours after rain stops and brown water clears before swimming. If you can still see any brown tint in the water, the clock has not started yet.
What triggers it: A wastewater collection or treatment system experiences a failure that results in raw or partially treated sewage being released into the environment. This can be a broken pipe, pump station failure, manhole overflow, or treatment plant malfunction. Municipal wastewater utilities are required by law to report these spills to the DOH.
What it means: Raw or undertreated human sewage has entered the waterway or coastal area. This is typically the most dangerous type of contamination because the sewage concentration is high and includes human pathogens that are directly infectious. The affected area depends on where the spill occurred and how much sewage was released — from a small localized area for a minor pipe break to an entire bay for a major pump station failure.
How long it lasts: The advisory remains until the spill is contained, the area is flushed by tides and currents, and follow-up bacteria testing confirms levels are back below the threshold. Duration varies widely — a small spill in open water may clear in 1–2 days, while a major spill in an enclosed bay can keep an advisory active for a week or more.
What you should do: Avoid all water contact in the specified area. Sewage spills are the one type of advisory where you should not rely solely on visual appearance — the water may look clear while still containing dangerous levels of pathogens. Wait for the DOH to officially lift the advisory. Oʻahu’s aging sewer infrastructure means these spills occur several times per year, often after heavy rain when the system is overwhelmed.
What triggers it: A permitted wastewater treatment facility discharges effluent that exceeds the limits set in its operating permit. This is different from a spill — the facility is still operating, but its discharge does not meet the required standards for one or more parameters (typically bacteria, nutrients, or suspended solids).
What it means: Treated wastewater that does not fully meet quality standards is being discharged, usually through an ocean outfall pipe. The contamination level is generally lower than a raw sewage spill because the water has been at least partially treated, but it still contains elevated levels of bacteria and nutrients that can affect nearby coastal waters. This most commonly affects beaches near wastewater treatment plant outfall locations.
How long it lasts: Until the facility resolves the issue and returns to compliance. This can be hours (for a temporary equipment malfunction) to weeks (for chronic capacity or infrastructure problems).
What you should do: Avoid swimming near the affected discharge point. The area of impact depends on ocean currents and the volume of discharge. If you see a Permit Exceedance advisory, check which facility is affected and stay away from beaches in the immediate vicinity of its outfall.
When the DOH tests beach water, they measure the concentration of enterococci bacteria in colony-forming units per 100 milliliters of water (CFU/100mL). Enterococci are not themselves the pathogen that makes you sick — they are indicator bacteria. Their presence in water indicates fecal contamination from humans or animals, which means other disease-causing organisms (viruses, pathogenic bacteria, parasites) are also likely present.
Hawaii uses the EPA’s 2012 recreational water quality criteria. The key number is 130 CFU/100mL — the Statistical Threshold Value (STV) for enterococci in marine waters. When a single beach sample exceeds this number, the DOH posts a Beach Advisory. The 130 CFU threshold is based on epidemiological studies that found a statistically significant increase in gastrointestinal illness among swimmers when enterococci exceeded this level. Specifically, it corresponds to an estimated illness rate of approximately 36 per 1,000 swimmers.
Bacteria levels in ocean water can change dramatically within hours depending on tides, currents, wind, sunlight, and rain. A sample taken Monday morning may show 40 CFU, but by Monday afternoon after a rain squall, the same spot could be at 500 CFU. The weekly testing schedule means you are always looking at data that is days old. Our site uses historical test data and geographic risk factors to estimate current conditions between official test dates.
In addition to the single-sample STV of 130, the EPA also sets a geometric mean criterion of 35 CFU/100mL calculated over a 30-day rolling window. If a beach’s geometric mean exceeds 35, it indicates a persistent contamination problem. Beaches that chronically exceed this threshold, like Hanalei Bay, get placed on the DOH’s impaired waters list under the federal Clean Water Act. Being “impaired” requires the state to develop a plan to address the contamination source, though progress on these plans has been slow.
This is the single most important thing to understand about Hawaii’s advisory system: the absence of an advisory does not mean the water was tested and found to be clean.
There are three common reasons a beach may show “no advisory”:
1. The beach is not monitored at all. The DOH regularly tests approximately 57 beaches across the state. Hawaii has over 250 swimmable beaches. That means roughly 80% of beaches are never tested and will never show an advisory regardless of actual conditions. If your beach is not on the monitoring list, “no advisory” is meaningless.
2. Testing has not happened recently. Even monitored beaches are only tested weekly. A beach that tested clean on Monday could be contaminated by Thursday’s rain and not show an advisory until the following Monday’s test results come back on Tuesday or Wednesday. That is a 5–6 day gap where conditions may have changed but the advisory system has not caught up.
3. Testing was paused during a brown water event. When the DOH issues a brown water advisory, they pause bacteria testing because the sediment makes lab analysis unreliable. So during the period of highest actual risk — right after a big storm — there is no bacteria data at all. The brown water advisory may be lifted based on visual assessment before bacteria levels have actually returned to normal.
Treat “no advisory” as neutral information, not positive information. It means there is no currently reported problem — but it does not mean the water was recently tested and confirmed clean. During and after rain, use the 72-hour rule regardless of advisory status. During dry weather at monitored beaches, no advisory is more reassuring.
The DOH CWB website is the official source for all advisory types. It shows a map of active advisories, historical test results, and advisory details. The site updates when new advisories are issued or lifted. You can filter by island and advisory type. The interface can be difficult to navigate on mobile devices, and it does not show historical risk patterns or beaches that are not officially monitored.
Safe to Swim Hawaii pulls data from the DOH API every 15 minutes and combines it with historical bacteria testing data, geographic risk analysis, and stream proximity data for over 100 beaches across all islands. When you look up a beach on our site, you see any active DOH advisory AND a historical risk rating based on years of test data, which helps fill in the gaps when no recent test is available. We also show advisories for nearby beaches, which the DOH site does not do.
On Safe to Swim Hawaii, active advisories appear at the top of each beach page as a red alert banner with the advisory type, affected location, and when it was posted. If there are no active advisories, you see a green “No Active DOH Alerts” banner. Below that, the historical risk rating (A+ through F) shows how the beach has performed over time based on bacteria testing data. A beach can show “no active alerts” while still having a D or F historical grade — meaning it frequently has problems even if nothing is flagged right now.
No data source can tell you what conditions look like right now at the beach. Before entering the water, always do a visual check. If the water has any brown tint, visible sediment plumes, debris, or if you can see brown water flowing from a stream or storm drain into the ocean nearby, stay out — regardless of what any advisory says or does not say. Clear, blue water is your green light. Brown or murky water is your red light.
Bacteria test failed. Avoid this specific beach. Check our site for nearby alternatives that may be unaffected. Wait for the advisory to be lifted before returning.
Visible runoff contamination. Avoid all affected beaches. Wait 72+ hours after rain stops AND brown water clears. Consider switching to a leeward beach that may not be affected.
Raw sewage in the water. Do not swim anywhere near the affected area. Water may look clear but still be contaminated. Wait for the DOH to officially lift the advisory.
Treatment plant over limit. Avoid beaches near the outfall point. Impact area depends on currents and discharge volume. Less severe than a raw sewage spill but still indicates elevated contamination.
No currently reported problem — but this does NOT mean the water was tested and found clean. If it rained recently, follow the 72-hour rule regardless. Check historical risk ratings on our site. Do a visual inspection before entering the water.
100+ beaches and 25+ hotels across all islands
Free alerts when water quality changes at your beach — brown water advisories, bacteria warnings, and all-clear notices.
No spam. Just safety alerts for your trip.
⚠️ Important Disclaimer
Safe to Swim Hawaii is an independent passion project — it is not affiliated with the Hawaii Department of Health or any government agency. Water quality ratings on this site are estimates based on publicly available testing data and geographic analysis. They are not real-time measurements and may not reflect current conditions. “No DOH Alerts” means no advisory is currently posted — it does not mean the water was tested and found safe. DOH only monitors a fraction of Hawaii’s beaches, and some areas have no regular testing at all.
Always verify current water quality conditions with the Hawaii Department of Health Clean Water Branch before entering the water.
When in doubt, don’t go out.