Ending the environmental threat that cesspools pose to Hawaii’s drinking and surface waters presents an enormous challenge — even with more than 30 years’ notice.

That’s what state lawmakers learned Wednesday during an informational briefing about a new state Department of Health report describing the scope of the problem and naming areas where priority should be given for removing cesspools.

The Legislature acknowledged the problem last year when it approved Act 125, requiring the elimination of all cesspools by 2050. Lawmakers also offered income tax credits to help with the upgrades.

Roughly 88,000 cesspools are found in Hawaii — more than any other state — and every day they release an estimated 53 million gallons of raw sewage into the ground, representing a significant risk to the environment, either as a threat to drinking water or by seeping into streams and coastal waters, according to the department’s report.

The report identifies 14 priority areas where upgrades are needed, led by Kahaluu on Oahu and Upcountry Maui areas, and estimated it would cost about $1.75 billion, or about $20,000 for each cesspool, to fix the problem.

But it’s unlikely many homeowners with cesspools will be able to afford the upgrades, and county governments may not be in a position to financially support the effort, lawmakers were told Wednesday.

For example, some 300 people from Upcountry Maui attended an informational meeting with the department Tuesday night. Many of them expressed concern about the financial burden of replacing their cesspools.

One of the attendees was state Sen. J. Kalani English (D, Molokai-­Lanai-East Maui), who said Maui property owners who have already researched the cesspool upgrades indicated costs could reach $80,000 per cesspool.

And one person from a large Upcountry family told English he has 27 cesspools. The rancher, who inherited the land with houses for family members, is a multimillionaire on paper but, in reality, can’t afford the price of the upgrades, English said.

English said the Upcountry area has many obstacles to cesspool upgrades, including small lots, impenetrable “blue rock” and the inability to hook up to a sewer system.

Lori Kahikina, Honolulu’s director of environmental services, told lawmakers it’s unlikely the city will be able to expand sewer service to Kahaluu anytime soon unless it is granted a special waiver from its court-ordered consent decree with the federal Environmental Protection Agency.

The $5.5 billion (in 2010 dollars) decree requires the city to, among other things, increase capacity at its Sand Island treatment plant through 2035.

Kahikina said she would be open to requesting the waiver, but she cautioned that costs could go up substantially if sewer transmission lines to the Kailua wastewater treatment plant also have to be upgraded to accommodate increased capacity.

Bill Kucharski, Hawaii County environmental management director, said the Health Department’s report identifies five areas on the Big Island, with about 25,000 cesspools stretching over 200 square miles.

“When you add up what that’s going to run, it comes to approximately $500 million to an island and a county that is not known for its excess cash,” he said. “So this is going to have a very significant impact not only on our people but the economy of the county.”

As part of the cesspool ban, the Legislature provided a temporary income tax credit for the cost of upgrading or converting a qualified cesspool to a septic tank system or an aerobic treatment system, or connecting to a sewer system. Under the law, a taxpayer may apply for a tax credit of up to $10,000 for cesspool upgrades during the next five years.

Kucharski said the residents of Kau and Puna don’t make enough money to be able to use the income tax credits.

“For them, this offering is absolutely and totally useless,” he said.

Kucharski and other officials urged the state to find additional — and less expensive — alternatives to the cesspool upgrades as proposed.