Sewage is killing the reefs of Hawaiʻi.
Sure, other factors are at play. There’s overfishing, especially of herbivores. Physical damage from hurricanes. Chemicals in runoff from former plantation fields and lawns, oils from highways and leaking underground tanks and pipes. And, not least, warming ocean temperatures that can result in bleached corals. All contribute to the harm.
The Hawaiʻi Department of Health has estimated that there are around 88,000 cesspools statewide, releasing some 55 million gallons a day (mgd) of untreated sewage to the environment.
If nothing is done to curb the flow of nutrients carried into nearshore waters by means of submarine groundwater flows, Hawaiʻi’s coastal ecosystems as we know them now are pretty well doomed.
They already have been seriously compromised. Last year, Greg Asner and colleagues published a report that found the major factor accounting for a 10-year decline of 45 percent in adult fish biomass along the west coast of Hawaiʻi island was nitrogen coming from land-based sewage disposal.
“Probably the biggest problem in terms of the connection between land and our reefs and our ocean’s health lies in onsite sewage disposal systems,” Asner said last month at a two-day virtual Sustainability Summit sponsored by the County of Hawaiʻi. In west Hawaiʻi island, most sewage disposal is through cesspools, accounting for some 680 million gallons of wastewater released to nearshore waters in 2017. (Not that sewage is the biggest factor in all locations surveyed. The steepest declines in fish biomass were seen in South Kona, Asner said, in areas where there is the least enforcement of fishing regulations.)
During a webinar last December on sewage impacts in Hawaiʻi, Element Environmental’s Daniel Amato noted that Hawaiʻi reefs evolved in a low-nutrient system. The state’s tens of thousands of cesspools are sending raw sewage straight “from your toilet into a hole in your yard. … When you add even small amounts of nutrients [to the ocean], it can really change the reef dynamics. … The reef is covered in these alien seaweeds that fish don’t like eating.”
Cesspools that serve single-family homes, apartment buildings, churches, schools, and businesses are not the only contributor. They are just one class – albeit the largest one – of what are termed onsite sewage disposal systems (OSDS). Other types of OSDS include septic tanks and aerobic systems that discharge to a seepage pit and systems that employ trenches and soil treatment. The total number of OSDS statewide is put at around 110,000.
Municipal wastewater plants that inject treated sewage into deep holes in the ground (such as those in Lahaina, Kihei, and Kahului, Maui) also contribute to the load. To address the inputs from centralized wastewater treatment plants that use injection wells will be challenging and expensive. But the very fact that they are centralized simplifies things.
When it comes to addressing the inputs from tens of thousands of individual cesspools, the problem is far more complicated.
For years, the state has attempted to figure out how best to convert cesspools – basically, brick- or concrete-walled pits that receive untreated sewage – to other systems that remove or reduce nutrients before releasing the effluent to the environment.
In 2015, in recognition of the problem, the Legislature attempted to encourage homeowners with cesspools near drinking water sources, streams, or coasts to hook up to municipal sewer systems or replace them more effective individual wastewater systems by allowing tax credits of up to $10,000 to offset the costs of upgrades, with a total of $5 million a year in tax credits available. In 2018, just 41 taxpayers claimed credits, while in the previous two years, the total was 47. The tax credit program expired at the end of last year, with the tax credits for 2018 and 2017 totaling less than half a million dollars. (The Department of Taxation has released no figures for the tax credit program for 2019 or 2020.)
In 2017, the Legislature mandated that all cesspools would have to be eliminated by 2050 – with certain exceptions (including small lot size, steep terrain, or “accessibility issues”).
That same year, the Department of Health (DOH) noted that replacing each cesspool with an improved treatment method could cost $20,000 or more, with the total cost (in 2017 dollars) of $1.75 billion to replace all 88,000 cesspools. That breaks down to $54.7 million per year, if construction costs were averaged over the entire period from 2018 through 2049, it noted.
In 2018, the Legislature authorized the DOH to establish a Cesspool Conversion Working Group to develop a plan for attaining the goal of eliminating all cesspools by mid-century. “Making sure people understand why cesspools are a problem is a big challenge,” the working groups’ Michael Mezzacapo said at the December webinar.
In a report just released in February, “Cesspool Conversion Finance Research Summary Report,” the average cost is now pegged at $23,000 per cesspool, for a total cost of more than $2 billion.
This would represent a financial hardship for households with annual incomes below $126,000, the report found. “Historically, affordability for water and wastewater service has been benchmarked as a percentage of median household income,” it notes, with the U.S. Environmental Protection Agency setting affordability for these services at a rate of less than 2 percent of household income.
“Approximately 97 percent of all residents with cesspools have an income less than $126,000 and thus would be financially burdened by the cost to convert,” the report states. “If a $10,000 rebate were provided to each household, approximately 85 percent would be financially burdened.”
Hawaiʻi County has more than 48,000 cesspools, more than any other county in the state. It also has a higher percentage of households – 71 percent – that are not connected to centralized wastewater treatment plants. More than 9,000 of the cesspools are in areas where drinking water sources are vulnerable to contamination; almost 16,000 are in areas where they may impact sensitive waters, including coastal environments, including some of the most popular beaches and surf spots in Kona and Hilo.
And it also has “the greatest affordability challenges,” the report notes, with a high percentage of the households now served by cesspools being unable to afford conversion costs without experiencing financial hardships.
Kauaʻi County has just over 12,000 cesspools, with 54 percent of all households on the island unconnected to sewage treatment plants. Again, 95 percent of those households would experience financial hardship if required to upgrade to an approved wastewater disposal system.
Just 22 percent of Maui County households use cesspools (around 14,000 in total), but the financial challenges of paying for upgrades would hit them hard as well. On Molokaʻi, 100 percent of the households relying now on cesspools would be unable to pay for them without undue hardship; on Maui island, that figure is 98 percent. (The report did not include figures for the island of Lanaʻi.)
The City and County of Honolulu has the lowest percentage of households served by cesspools – just 3 percent. Still, there are nearly 11,000 cesspools. Honolulu households have a higher income on average compared to other counties, yet many of those households now on cesspools would nonetheless face hardship if required to upgrade.
Now that the $10,000 tax credit is off the table, it is not clear what financial assistance will be available to homeowners served by cesspools.
There may, however, be new sewage treatment options that cost less than the estimated average of $23,000 per household. The study notes that some alternative sewage treatment technologies can cost as little as $9,000. Mezzacapo said the cesspool working group is evaluating waterless options, small-scale treatment facilities and “all of the available technologies” and their respective costs.
Amato added that there has been a lot of energy and money spent, including by the Bill and Melinda Gates Foundation, to reinvent the residential toilet. “Some have literally no waste; they make clean water; they don’t put wastewater into the ground; the solids can be used as fertilizer … I think that we should keep an eye on these technologies as they become more and more available,” Amato said.
This year Senate Bill 369 and a companion, House Bill 112, were introduced, establishing a “time of transfer wastewater inspection program” within the Department of Health. Anytime a residential property unconnected to a sewer system would be sold, a DOH inspector would determine whether the wastewater system required upgrades. If the system failed inspection, it would need to be replaced or repaired within one year, either by the seller or buyer.
The House measured died without a hearing. The Senate committees on Agriculture and the Environment and Ways and Means held hearings in February. Testifying in favor of the measure was the Department of Health, which noted that both the U.S. Environmental Protection Agency and the National Oceanic and Atmospheric Administration have advised that the state needs to develop an individual wastewater system inspection program if Hawaiʻi ‘s coastal nonpoint pollution control program is to be approved. If not, the DOH warned, the state could lose $1.1 million in federal funds. “This measure would be a starting point for developing an inspection program that is needed to satisfy federal requirements and it would also decrease the number of failing systems, thereby having a beneficial impact on water quality,” the department stated in its written testimony.
A number of nonprofits and individuals also testified in support. The only opposition was from the Hawaiʻi Association of Realtors.
Ken Hiraki, the association’s director of government affairs, said his group “supports the goal of protecting Hawaiʻi’s drinking water, streams, ground water, and ocean resources. However, it could be years or a property owner may never sell their property. As such, point of sale requirements are not a practical solution to address the issue of individual wastewater system repair.”
The Senate passed out the bill and forwarded it to the House for consideration. House leadership referred it to four committees; no hearing had been held on it by press time. The bill is unlikely to pass this year.
In addition to finding ways to get homeowners to convert their cesspools, Mezzacapo said it’s also important to get different levels of government to work in concert to prevent sewage discharges into the ocean.
Suppose someone wants to create a subdivision and have a high density of septic systems adjacent to the coast, in an area that the DOH has concerns about. “Is that the best thing to do? That takes planning between the two entities” — the county and the DOH — “and it takes outreach to homeowners,” he said.
— Patricia Tummons, with additional reporting by Teresa Dawson