If your home in Hawaii runs on a cesspool, you’ve probably heard that it has to go by 2050. That part is true. A lot of what else gets passed around is not. People hear that a sale forces a conversion, that the deadline moved, or that their neighborhood has to finish by 2030. None of those are law right now.
This guide walks through what Act 125 actually says, what has changed since 2017, and what the rules mean for a regular homeowner today. It’s current as of October 2026.
What Act 125 requires
Act 125 passed in 2017 and lives in the Hawaii Revised Statutes as section 342D-72. The core of it is one sentence: before January 1, 2050, every cesspool in the state has to be upgraded or converted to a wastewater system approved by the Director of Health, or connected to a sewer.
That’s it. There’s no earlier date for any neighborhood or priority level written into the law. Every cesspool owner, from a Hilo bungalow to a beach house on the North Shore, is working against the same deadline.
A 2022 amendment (Act 87) cleaned up the wording. The original law named septic systems and aerobic treatment units specifically. The new version says “director-approved wastewater system,” which leaves room for newer technologies the Department of Health (DOH) approves later. The 2050 date didn’t change.
What counts as a cesspool
The statute defines a cesspool as a hole in the ground that’s deeper than it is wide, takes in raw wastewater, holds the solids, and lets the liquid soak into the ground. Nothing treats the water first. In most of Hawaii that liquid ends up in groundwater, and from there it can reach streams, drinking water wells, and the ocean.
A septic tank is different. The tank separates solids and starts breaking waste down before the water goes to a leach field or seepage pit. If your home already has a permitted septic system, Act 125 doesn’t apply to you.
Not sure which one you have? On the neighbor islands, new homes could be built with cesspools right up until 2016, so age alone won’t settle it. Your property records, an old permit, or a quick inspection will tell you.
How many homes this affects
Depending on which data set you use, Hawaii has somewhere between 83,000 and 88,000 cesspools. DOH’s long-standing figure is about 88,000, putting out roughly 53 million gallons of untreated wastewater every day. A newer University of Hawaii analysis counts a little over 83,000.
Either way, Hawaii Island carries the biggest share. Nearly 50,000 of the state’s cesspools are on the Big Island, more than half the total.
You can’t build a new cesspool anymore
Since March 21, 2016, state rules (Hawaii Administrative Rules, Chapter 11-62) have banned new cesspools everywhere in Hawaii. Any new home has to have an approved system from the start. Oahu had already stopped allowing them before that, but the 2016 change made it statewide.
There’s also an older federal rule. The EPA banned large-capacity cesspools in 2005. “Large-capacity” means a cesspool serving more than one home, or a non-residential one that can serve 20 or more people a day. A single-family home’s cesspool falls outside the federal ban, which is why Act 125 matters so much for regular homeowners.
What about priority levels?
You may have seen your area described as Priority 1, 2 or 3. Those levels come from the Hawaii Cesspool Prioritization Tool, built by the University of Hawaii with DOH. It scores each cesspool on how likely it is to harm people or the environment, based on things like how close it sits to reefs, streams and drinking water.
Here’s the important part: the law doesn’t attach a deadline to any priority level. A Priority 1 cesspool and a Priority 3 cesspool both have until 2050. Priority does matter in other ways, though. Some grant programs only fund higher-priority cesspools. And the same things that put a cesspool in Priority 1, like shallow groundwater or a reef nearby, can limit which system types work on the lot.
We put together a separate guide on how to look up your property’s priority level.
Did the deadline change in 2026?
No. A few bills tried to change it this year, and none passed.
- SB2243 and HB2060 would have spread the deadline out by priority class, with the last group running as late as 2080. SB2243 cleared one committee and stalled. HB2060 never got a hearing.
- HB376 went the other way. It would have moved Priority 1 cesspools up to 2035 and Priority 2 to 2040. It stalled in the House Finance Committee.
- HB1749 would have created a cesspool disclosure form for home sales. It made it to conference and died there.
The 2030 and 2035 targets you might see online came from a state working group’s 2022 recommendations. They’re recommendations, not law.
The legislature revisits this almost every year, so it’s worth checking back. We’ll update this page when anything passes.
Can you get an exemption?
Possibly, but don’t count on it. The law lets the Director of Health exempt a cesspool if the owner applies and shows a legitimate reason that converting isn’t feasible. The statute gives examples like a very small lot, steep land, poor soil, or a site that equipment can’t reach.
It’s up to the Director, and the law doesn’t spell out a formula. Many “impossible” lots turn out to have a workable option once an engineer looks at them, such as a compact treatment unit or a different layout. If you think your lot might qualify, get a site evaluation first so you know what’s really possible.
When you might have to convert before 2050
The deadline is 2050, but some situations can bring it forward. Under the state rules, DOH may require an upgrade when:
- You apply for a permit to add a bedroom or otherwise change how much wastewater the home produces.
- The cesspool has been pumped more than twice, or has spilled wastewater more than once, in the past 12 months.
- The cesspool discharges straight into the groundwater table.
- The system has caused pollution or a health problem, or has a deficiency the owner hasn’t fixed.
“May” is doing real work in that sentence. These aren’t automatic. In practice, though, DOH does use them. Its Kauai office, for example, says an upgrade is required when you pull a permit that adds enclosed living space like a bedroom or an ohana unit. The building permit is usually where this comes up, because DOH reviews those plans.
If you’re planning a remodel, talk to us or to DOH before you submit plans. It’s much easier to fold a conversion into a project you already have planned than to find out halfway through.
Selling a home doesn’t trigger a conversion
There’s no statewide rule requiring a cesspool to be converted when a property is sold. Draft rules in 2014 proposed one, but they were never signed, and the 2016 rules left it out.
That said, a cesspool with a 2050 deadline is something buyers care about, and Hawaii’s seller disclosure law covers anything that would measurably affect a property’s value. Our guide to buying or selling a home with a cesspool goes into more detail.
Help with the cost
Converting isn’t cheap, and the state knows it. A few programs exist or are coming:
- Act 204 (2026) set up a cesspool conversion loan fund run by the Hawaii Green Infrastructure Authority, with low-interest or forgivable loans and a preference for low- and moderate-income households. Applications haven’t opened yet; the agency expects a late 2026 start.
- Act 153 (2022) created a DOH pilot grant of up to $20,000 for owners in Priority 1 or 2 areas who met income limits. The $5 million ran out within a couple of weeks of opening in 2023.
- County programs come and go. Kauai is running its second round of cesspool grants this fall.
Our guide to cesspool conversion grants and loans tracks what’s open right now, and our cost guide breaks down what a conversion runs.
What to do now
You don’t need to panic, but waiting until the late 2040s is a bad plan. Contractors, engineers and DOH reviewers will be swamped, and prices tend to follow demand. Here’s a sensible order of operations:
- Confirm you have a cesspool and find out its priority level.
- Get a site evaluation so you know which system types fit your lot.
- Watch for grant and loan programs and apply when one opens.
- If you’re planning a remodel or addition, plan the conversion at the same time.
When you’re ready, we can walk your property with you and explain your options. Request a free estimate.
Frequently Asked Questions
What is the cesspool deadline in Hawaii?
Every cesspool in Hawaii has to be upgraded, converted, or connected to a sewer before January 1, 2050, unless the Director of Health grants an exemption. That’s the only deadline in state law as of October 2026.
Does Act 125 apply to septic tanks?
No. It only applies to cesspools. If your home has a permitted septic system or aerobic treatment unit, you’re already in compliance.
Is my cesspool on an earlier deadline because it’s Priority 1?
Not under current law. Priority levels help target grants and may affect which system DOH approves for your lot, but the deadline is 2050 for every priority level. Bills to set earlier dates for Priority 1 and 2 cesspools have been introduced but haven’t passed.
Do I have to convert my cesspool if I sell my house?
There’s no statewide requirement to convert at sale. You should still disclose the cesspool, since Hawaii law requires sellers to disclose anything that would measurably affect the property’s value.
Will adding a bedroom force me to convert?
It can. State rules let DOH require an upgrade when a building permit changes the home’s wastewater, and adding a bedroom is the most common example. DOH reviews building plans, so this usually comes up during permitting.
Can I still build a new cesspool?
No. New cesspools have been banned statewide since March 21, 2016.
Where can I check the latest rules?
The DOH Wastewater Branch is the official source. This article is general information, not legal advice. For questions about a specific property, check with DOH or a licensed professional.
