Cesspool Conversion in Hawaii: What Act 125 Means for Oahu Homeowners

Hawaii has more cesspools than any other state, and they release untreated wastewater into the ground — and eventually into groundwater and coastal waters. In 2017 the legislature passed Act 125, which requires every cesspool in the state to be upgraded, converted or connected to a sewer system by 2050.

Do you have a cesspool?

Most homes in urban Honolulu are on city sewer, but many properties in rural and outer areas of Oahu — parts of the North Shore, Windward coast and Central Oahu among them — still use cesspools. Your property records, a previous inspection report or a quick check by a pro can tell you what you have.

What are the options?

If a public sewer line is available nearby, connecting to it is usually the most straightforward route. Where sewer isn't available, the common upgrades are a septic system with a leach field or an aerobic treatment unit, which treats wastewater more thoroughly and can suit smaller lots. Soil, lot size and site conditions decide what will work.

Why plan before 2050

A home sale, a failing cesspool or new sewer access nearby can all bring the decision forward. Conversion projects require design, permits and qualified contractors, and demand will only climb as the deadline approaches. Planning early gives you time to budget and to look into any state or county assistance programs that may be available.

Start with an inspection

A camera inspection of your lines and an assessment of your current system is the first step. Tell us about your property through the form below and we'll connect you with a local pro who can explain your options.