Cesspool conversion FAQ

Yes. Hawaiʻi law (Act 125 (2017), HRS §342D-72) requires every cesspool in the state to be upgraded to an approved system, converted, or connected to a sewer before January 1, 2050. New cesspools have been banned since 2016.

The Department of Health may grant limited exemptions in difficult situations, such as very small lots, steep terrain, poor soils, or access problems.

Not under current law — 2050 applies everywhere. In 2022 the State’s Cesspool Conversion Working Group recommended earlier deadlines for the highest-priority areas (2030 for Priority 1 and 2035 for Priority 2), and bills to change the deadlines are introduced most years. None has passed so far, but the rules could change.

The State’s Hawaiʻi Cesspool Prioritization Tool, developed by the University of Hawaiʻi Water Resources Research Center with the Department of Health, ranks areas by how much risk their cesspools pose to drinking water, streams, and coastal waters.

On Hawaiʻi Island, Priority 1 areas include Kailua-Kona, Hōlualoa, and Kawaihae–Waikoloa. Priority 2 includes Keaukaha–Panaʻewa, Villa Franca–Kaikoʻo, University–Houselots, Kaumalumalu–Keauhou, and Kealakehe. Most of Puna, Kaʻū, Hāmākua, and Hilo is Priority 3.

Check My Property shows the priority area for your address as soon as you enter it. For the places on the island where cesspools are doing the most harm, see Why Hawaiʻi Island (ainaforce.com/hawaii-island).

Not under current state law. Proposals to require conversion or disclosure at sale have been introduced in recent sessions but have not passed. Buyers, lenders, and inspectors may still ask about the cesspool, so knowing your options can help.

It depends heavily on the property. The State’s working group found past conversions ranged from $9,000 to more than $60,000, averaging about $23,000 (in 2020 dollars). Hawaiʻi County’s Department of Environmental Management has estimated $30,000 to $70,000 for an on-site conversion today.

Soil, slope, lot size, access for equipment, the number of bedrooms, and distance to water all affect the system and the cost. That is why we start with the property.

As of October 2026:

• In 2026 the Legislature created a Cesspool Conversion Revolving Loan Fund (Act 204) for low-interest and forgivable loans, run by the Hawaiʻi Green Infrastructure Authority. It is still being set up and is not accepting applications yet.

• The State’s earlier cesspool tax credit expired in 2020, and the Department of Health’s pilot grant program ended in 2024.

• Some owner-occupants may qualify for USDA Rural Development home repair loans and grants, depending on income, age, and location.

ʻĀina Force tracks these programs and is working with local government. When you add your property, we’ll help you understand which options may apply. Funding and eligibility are never guaranteed.

Usually a septic system or an aerobic treatment unit with a disposal field, or a sewer connection where sewer lines are available. The right system depends on soil, slope, groundwater, lot size, and Department of Health requirements, which is why a property review and engineering come first.

About 48,600 — more than half of the about 83,000 in the state. Together they release about 29 million gallons of untreated wastewater into the ground every day.

We help homeowners navigate the whole conversion — property review, funding guidance, and coordinating information, introductions, documentation, and communication with the professionals involved. Engineering, permitting, installation, and inspections are performed under separate agreements by appropriately licensed independent engineers and contractors.

Checking your property is free and there is no obligation. We’re accepting Hawaiʻi Island properties into our early pilot now.