Shortening a deadline on something important is effective in getting the attention of the target audience, especially when allotting ample time hasn’t been doing the job.

This is why the recommendation by a state task force to lop well over a decade off the time many homeowners have to shut down their cesspools is the correct course to take. And the fact that the group is proposing tax incentives to help cover the costs of converting to wastewater treatment boosts the chances that moving up the date will actually work.

The nearly 5-year-old Cesspool Conversion Working Group has advanced that strategy to the Legislature in its latest report, which lawmakers should heed when they convene Jan. 18.

A total of roughly 83,000 homeowner cesspools serve residences in Hawaii. In 2005, the U.S. Environmental Protection Agency banned the use of large-capacity cesspools, including those serving multiple residences.

Most Hawaii cesspools serve only single-family residences and are not regulated by the EPA. Even so, as recently as 2021, the EPA slapped the state with nearly $222,000 in fines for operating seven large-capacity cesspools on Kauai.

It also was still a shameful delay that the state did not make its own substantial move to curb the problem until 2015 when construction of new cesspools was banned.

And it wasn’t until 2017 that the Legislature initially set the date at 2050 for the conversion of cesspools, in order to remove the risk of sewage leaching into groundwater, streams or the ocean.

The following year, lawmakers established the working group, whose latest report for the 2023 session recommends moving up the deadline to 2035 for 12,367 cesspools.

The 13,821 cesspools that pose an even greater environmental hazard must be shut down by 2030, if the proposal is accepted, as it should be.

The state had set the deadline far forward, at 2050, in large part because the homeowner expense of upgrading to conventional sewage treatment is so great.

According to the report, the average cost to convert to an onsite wastewater treatment system is $24,000 — or $210 per month, assuming monthly financing arrangements can be made.

The working group calculated that for those with incomes under $126,000 annually, that cost would amount to 2% of income and thus would pose a financial burden. And about 97% of all Hawaii residents with cesspools fall into that income category, the report states.

To ease the burden, the group recommends that state and county officials develop incentive programs, a mix of financial grants, tax credits and low-interest loans. Making these available in conjunction with a shorter deadline would make earlier conversion more feasible and likely.

Federal aid also should be sought by local government to help pay for the total upgrade costs, with estimates ranging between $880 million and $5.3 billion.

It is clearly worth the investment, given the risks to the environment and public health. According to the EPA’s report on “Cesspools in Hawaii” (epa.gov/uic/cesspools-hawaii), “discharge of raw, untreated sewage to a cesspool can contaminate oceans, streams and groundwater by releasing disease-causing pathogens and nitrates,” the latter causing damage to coral reefs and other aquatic ecosystems.

When endorsing the original deadline set in 2017 through Act 125, Sierra Club of Hawaii provided testimony with more details about the health hazards: Bacteria and viruses can cause gastroenteritis, Hepatitis A, conjunctivitis, leptospirosis, salmonellosis and cholera, among other ailments.

If this sounds scary, it should. Cesspools are a scourge, one to be excised without further delay.