This is the first week of 2026 where every Hawaiian island has at least one active advisory. Last week, the Big Island and Kauaʻi were fully clear. This week, Kauaʻi is back on the board with an island-wide Brown Water Advisory plus the Waimea wastewater spill — still open nine days after a 72,000-gallon discharge reached the Waimea River. On Oʻahu, the persistent North Shore bacteria story has now stretched to 19 days. Maui picked up another Brown Water Advisory spanning the entire Kaʻanapali corridor. The Kona Low aftermath is still playing out — and the wastewater system has not fully recovered.
On April 10, approximately 72,000 gallons of partially treated wastewater overflowed from an effluent tank at the Waimea Wastewater Treatment Plant on Kauaʻiʻs west side. The discharge reached the Waimea River and, based on local reporting and hydrological pattern, likely carried into Kikiaola Small Boat Harbor. The Hawaii Department of Health issued a Sewage Spill advisory shortly after and — as of this report — it remains active.
Nine days is unusually long for a Sewage Spill advisory to stay open. The DOH typically reopens a site once follow-up bacteria testing comes back below the 130 CFU/100mL enterococci threshold. When an advisory persists past a week, it almost always means either (a) the follow-up test came back positive, (b) the DOH is waiting on additional samples, or (c) the plant has not confirmed a full fix to the overflow condition. For swimmers, the practical takeaway is the same: stay out of the water near the Waimea River mouth, Kikiaola Harbor, and along the Waimea shoreline.
The wider context is that west Kauaʻi is a dry, small-population coastline. Kikiaola Harbor is used by fishermen and divers. It is not a tourist swimming zone, but it is a working coastline, and any west-side visitor should route around the Waimea River until the advisory is lifted. Decent alternatives on Kauaʻi this week include Poʻipu Beach on the south shore and Anini Beach on the north shore, which is reef-protected and outside the Waimea spill zone.
We will update this report when the Waimea advisory is lifted. Our Kauaʻi page pulls live DOH status, so if you are planning a trip to west Kauaʻi, check there for current status before heading out.
Last week we flagged the North Shore bacteria situation at 14 days. This week it is 19 days. The same four Beach Advisories issued on March 31 remain active: Haleiwa Beach Park, Puaena Point (adjacent to Haleiwa), Mokuleia, and Kawaihapai (the Dillingham area on the far North Shore).
Nineteen days of sustained elevated bacteria with no resolution is rare. In our experience tracking DOH data, the reasons are usually one of three things. One: the DOH has not re-tested recently enough to lift the advisory (resource-constrained during a busy month). Two: each re-test continues to come back above 130 CFU/100mL, indicating a real persistent contamination source. Three: the original source has cleared but a secondary source — stream discharge, agricultural runoff, a nearby cesspool failure — is now dominant. Given the length of time, option 2 or 3 is the most likely explanation.
Practically: avoid entering the water between Mokuleia and Haleiwa. If you are surfing the North Shore, shift further east toward Pipeline/Ehukai or Turtle Bay, both of which are outside the advisory area. Surfers should still be aware that bacteria can move with currents and that the entire North Shore received the April 10 island-wide Brown Water Advisory recovery period.
Mauiʻs situation has not improved since last week — and in one respect, it has spread. The Brown Water Advisory that initially covered Hanakaoʻo Beach Park now extends from Hanakaoʻo to Wahikuli, covering essentially the entire Kaʻanapali resort corridor from Black Rock down toward Lahaina. A separate advisory covers Puamana Beach Park north of Launiupoko. Between those two, much of the west Maui tourist beach corridor is under some form of BWA.
Where on Maui is still outside the advisories? Wailea, Makena (Big Beach), and Kapalua Bay remain outside the current advisory zones. Wailea and Makena sit on the dry south side with less stream runoff. Kapalua is a sheltered bay, far north of the Kaʻanapali BWA area. These three are the most reliable Maui picks this week, but always check live status on our Maui page before heading out.
Last week Kauaʻi had zero advisories. This week it has two: the Waimea sewage spill (covered above) and a fresh island-wide Brown Water Advisory. The island-wide BWA was issued in response to this weekʻs rain and debris conditions and covers stream-mouth zones across the entire island.
Where on Kauaʻi is still a good choice? Poʻipu Beach on the south shore and Anini Beach on the north shore are both outside the Waimea spill zone. Anini in particular sits inside a long reef that breaks down incoming swell and filters runoff — it is the clearest water on Kauaʻi most of the year. Kalapaki Beach near Lihue has a chronic contamination problem from Nawiliwili Stream regardless of advisory status — it has failed 100% of bacteria tests since 2016 — so that is a pass this week and every week.
The Big Islandʻs one active advisory is a Brown Water Advisory in the Ninole area along the Hamakua Coast (the windward, wet side north of Hilo). Ninole is a small community with a black sand beach and a stream mouth — this is a routine post-rain BWA for that specific location. The advisory has been active for 16 days now, which is longer than we would expect, but there is no indication it reflects a wider issue.
This week the hierarchy is clear. Big Island is the cleanest mainstream option — only one active advisory, and that one is in a remote area. Second place goes to Kauaʻiʻs north and south shores specifically (Poʻipu and Anini), if you avoid the west side. Third is Mauiʻs south side (Wailea, Makena, Kapalua), keeping well clear of Kaʻanapali and Kihei. Oʻahu requires the most care this week — the North Shore bacteria problem is persistent, and the island-wide BWA from April 10 has not been formally lifted. Stick to Waikiki (check our Waikiki brown water advisory today page if heavy rain has hit), Ala Moana, and reef-protected spots like Hanauma Bay and Ko Olina.
If you are mid-trip and already at a specific beach, check our guide to beaches less affected by Brown Water Advisories. It names the reef-protected and sheltered beaches on each island that tend to stay lower-risk during advisory cycles. We launched that guide this week specifically because “where CAN I swim right now” is the most common question we receive after a BWA hits.
Regardless of where you are headed: wait at least 72 hours after heavy rain before entering the ocean. That rule applies even when no advisory is posted. The DOH only monitors 57 of 300+ Hawaiian beaches — the absence of an advisory does not mean the absence of contamination. Stay out of brown or murky water. If a stream or river is flowing into the ocean at your beach, consider moving down the coast. Read our full Swimming After Rain guide for the detail.
Hawaiiʻs water quality follows a seasonal pattern. The wet season runs roughly October through April, peaking from December through March. April is usually the tail of that cycle. This April has been rougher than usual because of the early-April Kona Low storm system that saturated catchments across all four major islands. Normally by late April, stream flow has dropped, cesspools have drained, and the DOH is closing out lingering advisories faster than new ones appear. That has not happened this year.
The deeper structural issue is that Hawaii has an estimated 88,000 cesspools statewide — more than any other U.S. state — and when heavy rain saturates the ground above them, they leach nitrogen, phosphorus, and fecal bacteria into streams that feed the coast. State law requires all cesspools to be replaced by 2050, but progress is slow. Big rain events like the April Kona Low reveal the systemʻs fragility: one storm saturates the cesspool-heavy coastlines, and it takes weeks for the ocean to clear.
If you are reading this trying to plan an April or early-May Hawaii trip: the water is still swimmable in most places, most days. Just choose your beach with the data in front of you, and always verify live status before heading out. Our Hawaiiʻs Worst Beaches for Bacteria page maintains a year-round list of the chronically contaminated spots so you know which ones to avoid regardless of what week it is.
⚠️ 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 information in this report is based on publicly available data from the DOH, USGS, NOAA, NDBC, and NWS. Conditions change rapidly. Data in this report reflects conditions observed during the week of April 19, 2026 and may not reflect current conditions.
Always verify current water quality conditions with the Hawaii Department of Health Clean Water Branch before entering the water. This report is for informational purposes only and should not be the sole basis for any swimming decisions.
When in doubt, don't go out.