Clean Water Now - Improve Wastewater Treatment at Sand Island

The Hawaiʻi Department of Health has released a draft Clean Water Act permit for the Sand Island Wastewater Treatment Facility in Honolulu. The draft permit rubberstamps extremely high limits on bacteria and allows for the continued pollution of Mamala bay putting public and environmental health at risk. The public comment period runs from March 15 to April 15.

Link to the permit notice

Up to 90 million gallons of treated wastewater are discharged into the ocean at Mamala Bay each day from the Sand Island Wastewater Treatment Plant, just offshore from Oʻahu’s iconic South Shore. While this wastewater is “treated,” the facility is not yet operating at full secondary treatment, and the current permit allows extremely high levels of bacteria — far above what is considered safe for waters where people swim, surf, and play. High bacteria levels can make people sick, and monitoring shows repeated violations, including a sample of 78,622 enterococcus in July 2025.

This pollution doesn’t stay offshore. Research in Mamala Bay shows that wastewater discharged from the outfall can move back toward shore under certain conditions, including to Waikīkī, Ala Moana, and other South Shore beaches. At the same time, the system relies on a “mixing zone,” which allows pollution to exceed safety standards near the discharge point based on the assumption it will be diluted. But dilution does not remove pollution — and when contamination can travel, it creates real risks to public health. The fact that the discharge is out in the Bay doesn’t excuse this approach — residents and visitors should still be able to engage in primary recreation there, like canoeing, without the high risk of getting sick from sewage-borne illnesses.

This issue has been recognized for decades, with federal enforcement and a 2010 consent decree requiring long-term upgrades. But full compliance is not required until 2038, and water quality impacts are happening now.

With increasing climate-driven flooding, aging infrastructure, and growing urban population placing immense stress on a failing system, the public should not have to wait on a decades-long consent decree for clean water.

Our goal is to ensure the NPDES permit truly safeguards public and environmental health now by lowering allowable bacteria limits (enterococcus), challenging reliance on the mixing zone, and strengthening pretreatment and source control. This is a public health issue driven by system-wide infrastructure failure.

We can’t wait for clean water — we need it now.