Published September 29, 2026
What Act 125 Requires
A cesspool is an unlined underground pit, most often a buried concrete cylinder or a rock-lined shaft, that collects a home’s raw sewage and lets it seep straight into the surrounding soil and groundwater with no treatment step in between. Act 125, passed by the state legislature in 2017, requires that every cesspool in Hawaii be upgraded, converted to another wastewater system, or connected to a sewer line before January 1, 2050. According to the Hawaii Department of Health (health.hawaii.gov), the law applies statewide and covers every cesspool regardless of size, with the narrow exception of a property that has been granted an exemption by the state health director after documenting that conversion is not feasible. There is no carve-out for the age of the system or how well it has performed. If a property still uses a cesspool, the deadline applies to it.
Which Cesspools the State Prioritizes First
The 2050 deadline is the same for every cesspool in the state, but the Department of Health has ranked cesspools by the risk they pose, and that ranking decides which properties get pushed toward conversion first and which ones qualify for assistance sooner. Priority level 1 covers cesspools the department considers a significant risk to drinking water, to human health, or to sensitive coastal and stream waters. Priority level 2 covers cesspools with the potential to affect a drinking water source. Priority level 3 covers cesspools with the potential to affect other sensitive waters. Priority level 4 is every cesspool the department has not yet placed in one of the first three tiers. A homeowner in a lower tier still faces the same statutory deadline. The ranking mainly determines the order in which state assistance programs reach different properties, not whether the law applies.
Your Three Conversion Options
Every path to compliance runs through one of three systems, and the Department of Health’s own guidance for cesspool owners names all three.
| Option | What it is | Best fit |
|---|---|---|
| Septic tank system | A buried tank that separates solids from liquid, with bacteria digesting part of the solids, before the liquid moves to a drain field | Most lots with enough space and soil suited to a drain field |
| Aerobic treatment unit (ATU) | A tank that adds oxygen to speed up the bacteria breaking down waste, producing a more finished effluent before it reaches the soil | Smaller lots or soil that a conventional drain field will not accept |
| Sewer connection | A pipe that carries wastewater off the property to a treatment plant, removing the household from the conversion question entirely | Properties near an existing line, where extending it is practical |
A septic tank system separates solids from liquid inside a buried tank, where bacteria digest part of the solid load, and sends the remaining liquid out to a drain field, the buried network of perforated pipe and gravel that lets soil filter it the rest of the way. An aerobic treatment unit, or ATU, adds oxygen to wastewater inside the tank, which speeds up the bacteria breaking solids down and produces a cleaner effluent before it reaches the soil; it is often the option a smaller lot or poorer soil calls for when a conventional drain field will not fit or will not perform. A sewer connection sends wastewater off the property entirely to a treatment plant. A licensed wastewater engineer determines which of the three a specific property qualifies for, based on lot size, soil, and how close the property sits to an existing line.
What Cost Help Exists
Converting a cesspool costs real money, and Hawaii has published two forms of help, though only one is still open. A temporary state income tax credit, described in the Department of Health’s own instructions for cesspool owners (health.hawaii.gov), covered up to $10,000 of the documented cost of upgrading or converting a qualifying cesspool, for cesspools within 500 feet of a shoreline, a stream or a wetland, within a source-water assessment area, or serving multiple dwellings or 20 or more people a day. That credit’s tax years ran from 2016 through 2020, so it is no longer available to a homeowner starting a conversion today. The department’s current program is a pilot cesspool conversion grant, created under a 2022 act and opened to applications in 2023 per health.hawaii.gov, which reimburses up to $20,000 of a household’s conversion or sewer-connection cost. It is limited to properties in the department’s highest two priority tiers and to households under an income limit, and it is awarded on a first-come, first-served basis while funding lasts, so a homeowner planning a conversion should confirm current funding directly with the department rather than assume the program is still open.
Keeping an Existing Cesspool Working Until Conversion
None of that changes what a cesspool still in use needs today. A cesspool relies on the same bacteria a septic tank does to break down the solids a household sends it, but it has no drain field and no second stage. Whatever the bacteria do not digest, and whatever liquid the pit produces, goes straight into the soil around it, which is exactly why the state is phasing cesspools out. Until a property converts, keeping that biology working is what keeps a cesspool from backing up, overflowing at the surface, or producing a strong odor, and it calls for a smaller version of the same maintenance a conventional septic tank needs: regular pumping on a schedule, with bacteria that are not overwhelmed between pumpings.
DRP Accelerator carries usable oxygen to the bacteria already living in your tank. We add no bacteria, no enzymes and no chemical additives. In a cesspool the same mechanism applies: more oxygen for the bacteria already present means they digest more of the solid load before it reaches the soil, which is the same job enzyme products and bacteria packets claim and do not always deliver. It will not shorten the path to compliance and it does not change the 2050 deadline or make a property exempt. It is the maintenance step between now and conversion, whichever of the three systems a property eventually converts to. A biological treatment built for a household tank works the same way whether that tank is a cesspool today or a septic system after conversion.
When to Call a Licensed Professional
Some signs mean stop planning and call today instead:
- Sewage surfacing at the ground above or around the cesspool.
- Sewage backing up into a sink, tub or toilet.
- A strong gas smell near an open cesspool lid, a manhole or any confined space. Leave the area and call a professional rather than looking closer.
- Every drain in the house running slow at the same time.
- Any conversion, upgrade or repair work itself. State law requires a licensed wastewater engineer to design the replacement system and a licensed contractor to build it, with the plans reviewed by the state before construction starts.
None of those wait for 2050. A cesspool that is already failing needs a professional now, regardless of what year is written into a household’s compliance timeline.
Where to Buy
The home product is sold as Accelerator by Dr. Pooper at doctorpooper.com, as a tablet you drop in the toilet and flush or as a liquid concentrate, used on a schedule between pumpings. The buttons on this page take you there. Converting a cesspool is a legal deadline and a construction project. Keeping the one you have working in the meantime is a much smaller decision, and it starts there.