Coastal Chemistry Corner: It’s Time to Stop Dumping Sewage in the Ocean

Coastal Chemistry Corner: It’s Time to Stop Dumping Sewage in the Ocean

It seems like a no-brainer. 

While it is already illegal to pollute the ocean—in technical terms, state and federal law broadly prohibits “discharg[ing] any pollutant into state waters”^[1] without a permit—the rules are set to expand in 2027 to require a permit for discharges of both treated and raw sewage into water bodies. But what counts as a “pollutant”? And what does “discharge into state waters” even mean? 

“Pollutant” is defined very broadly in the law and encompasses everything from radioactive waste to sewage, dirt, and even heat. 

What “discharge into state waters” means, however, has been the subject of long-standing legal battles over the scope of the U.S. Clean Water Act. It was at the heart of the matter in a recent U.S. Supreme Court ruling^[2] that led the court to establish the concept of “functionally equivalent direct discharge”, a technical phrase for recognizing the basic fact that pollution travels through groundwater and reaches the ocean. Importantly, the ruling affirmed that the Clean Water Act applies beyond situations where a pipe spills directly into the ocean. 

Although the details are still being worked out to determine exactly where and how to draw the line from a regulatory standpoint^[3], the vast majority of sewage in West Hawaiʻi is untreated before being discharged to the environment, and is therefore already classified as a pollutant. Because our island landscapes are highly permeable, much of this waste rapidly drains to the ocean without a chance to be broken down by microbes and bacteria. 

Decades of research have documented the tight connection between sewage disposal, groundwater contamination, and harm to coral reefs in West Hawaiʻi (Gove et al. 2023, for example). Despite this clear diagnosis, the typical avenue for generating clean-up plans has thus far been avoided because the problem seems intractable, stemming from too many unregulated individual wastewater systems that have historically not required discharge permits.

Now, prompted by these mandates at the state and federal level, regulators are beginning to develop a system for discharge permits that will encompass the tens of thousands of wastewater point sources across the state. A vast majority of these are the legacy cesspools on Hawaiʻi Island, which are already widely known and discussed as sources of groundwater contamination. Typically overlooked, but just as problematic, are the growing number of conventional septic systems with leach fields that are highly prone to failure in lava rock.

Although the Supreme Court took great care to ensure that their ruling would not suddenly require that every homeowner in the country with a septic tank apply for a permit, they also made it abundantly clear that states have broad responsibility and authority to mitigate harms arising from discharges to groundwater. By 2027, all wastewater systems, regardless of their level of treatment technology, will require discharge permits if they are close enough to the shoreline or causing enough environmental damage to meet the “functional equivalency” benchmark.

^[1] HRS §342D-50

^[2] County of Maui v. Hawaii Wildlife Fund, 590 U.S. (2020)

^[3] EPA Draft Guidance Regarding NPDES Permitting of Certain Discharges through Groundwater to Surface Waters https://www.epa.gov/npdes/releases-point-source-groundwater

n.b. vessel sewage discharges are handled in a separate section of the Clean Water Act