Septic Installation & Cesspool Conversion in Leilani Estates & Lanipuna Gardens

We install septic systems and convert cesspools in Leilani Estates and Lanipuna Gardens, about half an hour from our equipment yard in Keaau. Most of the work here starts from one fact: Leilani is where the 2018 eruption broke through the ground, and many families in this neighborhood lost their homes. Our job is to help the people who are staying, repairing or rebuilding get a wastewater system that passes review and holds up on this ground.

Leilani and Lanipuna by the Numbers

  • Laid out around 1960. The original developers bought about 2,400 acres from Olaa Sugar Company in 1959 and began selling one-acre lots in early 1960, the same winter as the Kapoho eruption. The subdivision has more than 2,000 lots, and one acre leaves room for a tank and leach field with the required setbacks.
  • About 750 to 770 feet in elevation, in the lowland rain belt of lower Puna.
  • Roughly 125 inches of rain a year, per the University of Hawaii Rainfall Atlas. Systems here have to cope with long wet spells.
  • Census counts. The 2010 Census found 1,560 people and 807 housing units in the Leilani Estates CDP. The 2020 Census found 1,139 people in 514 households, with 657 housing units. The drop tracks what the eruption took.
  • Lava hazard zone 1. USGS places Leilani Estates, Lanipuna Gardens and Kapoho in zone 1, the highest hazard zone, because they sit on Kilauea’s East Rift Zone.

What 2018 Did to the Ground Here

The first ground cracks of the 2018 lower East Rift Zone eruption opened in and next to Leilani Estates on May 2 and 3, 2018. Over three months, 24 fissures erupted, 14 of them inside Leilani. The largest, fissure 8 on Luana Street, sent lava all the way to Kapoho Bay. Across lower Puna, Hawaii County counted 716 dwellings destroyed. Lanipuna Gardens was evacuated the same day as Leilani, and one fissure opened near its entrance.

For septic planning, that leaves three kinds of ground:

  • Older surfaces the 2018 flows missed. Two soil series NRCS describes for lower Puna below 1,200 feet, Opihikao and Malama, have only about 2 to 12 inches of organic soil and ash over pahoehoe or aa lava.
  • 2018 lava, which has no soil at all and can be thick, irregular and full of voids.
  • Cracked ground near the fissure line. In late 2018, a resident whose home was spared described a neighboring property with large cracks still releasing gas.

On fractured lava, HAR 11-62 requires a soil replacement system with at least 3 feet of separation to groundwater. In Leilani, the design question is mostly how much rock has to come out and how much fill has to come in. We also want the engineer to look closely at any visible cracking before choosing where the tank and field go. Nobody wants a leach field across a crack.

Projects We See in Leilani Estates

These are the situations homeowners here usually call about:

  • Surviving homes still on cesspools. Any house built before March 2016 may have one, and it falls under the statewide 2050 deadline.
  • Rebuilding where the house was lost. A rebuild needs a county building permit, and on Hawaii Island DOH reviews the wastewater plan before that permit is signed off. New cesspools have been banned since 2016.
  • Repairs and additions. If a permit adds bedrooms, DOH can require an upgrade, and HAR 11-62 treats any room of at least 70 square feet as a bedroom.
  • Smaller replacement homes. Many owners are rebuilding smaller. Systems are sized at 200 gallons per day per bedroom, with a 1,000-gallon minimum tank.

If your cesspool survived but the house did not, ask DOH before assuming anything about reuse. After the 2023 Kula fire on Maui, DOH issued guidance allowing limited reuse of existing cesspools for rebuilt homes there. We have not seen equivalent guidance for lower Puna. Our new home septic requirements guide walks through the permit steps for a rebuild.

Getting Equipment In After the Lava

Road access is the biggest practical issue here, and it is still changing:

  • Leilani Avenue is a private road. As of 2023 it ended at a guardrail, and the back third of the subdivision had no access or detour. Its reconstruction is part of a FEMA-funded road package for lower Puna.
  • Pohoiki Road. Work on a 4.5-mile section started in August 2025, with completion expected in the second quarter of 2027.
  • Lanipuna Gardens. In 2023, the county said the stretch of Lauone Street leading to Lanipuna Gardens would not be restored.

Before we quote, we need a legal route an excavator and a truck of fill can use. If your lot is past a lava closure, tell us up front.

Insurance, Lending and the Zone 1 Question

In May 2018, insurers placed moratoriums on new policies in the eruption area. The state Insurance Commissioner cancelled the one at the Hawaii Property Insurance Association, the insurer of last resort, though HPIA could still apply a waiting period. Carriers and rules have changed since then. If you are financing a rebuild, talk to your lender and insurer before paying for a septic design, because their requirements can set the timing of the whole project.

Rebuilding has gone on anyway. By May 2019, 127 building permits had been pulled in lava zone 1, and nearly half were in Leilani Estates.

Cesspool Rules and Funding for Leilani Owners

  • The 2050 deadline applies. Under Act 125, surviving cesspools here have until January 1, 2050 to be converted or connected to sewer. See our Act 125 explainer.
  • Priority status. Leilani is not one of the five Hawaii Island priority areas in the 2017 DOH report, though neighboring Kapoho is. You can check your parcel on the UH Cesspool Prioritization Tool.
  • Sewer. Ask the county Department of Environmental Management about any planned service.
  • Funding. The Act 204 state loan fund is not open yet; the Hawaii Green Infrastructure Authority expects a late 2026 launch. USDA Section 504 offers repair loans to very-low-income rural owners and small grants to those 62 and older, so check eligibility with the USDA office in Hilo. Our grants and loans page tracks what is open.

Neighbors Along the Rift

Start With Where Your Lot Stands

Tell us your street, whether the house is standing, and how you reach the lot today. We’ll tell you what we know about the ground in that part of the subdivision and what the next step is. Request a free estimate

Frequently Asked Questions

Can I rebuild in Leilani Estates with a cesspool?

No new cesspools have been allowed in Hawaii since March 21, 2016, so a new home needs an approved system. Whether a cesspool that survived the eruption can serve a rebuilt house is a DOH decision.

Does lava zone 1 change the septic rules?

No. The HAR 11-62 rules are the same as elsewhere. Zone 1 mostly affects insurance, lending and how much you want to invest.

My lot borders the 2018 flow. Is that a problem for a leach field?

It can be. Fresh lava and cracked ground count as fractured lava, which means a soil replacement system. The engineer’s soil profile shows how much rock has to be replaced.

Can you reach lots past the Leilani Avenue closure?

Only if there is a legal route for equipment. Road work in lower Puna is ongoing, so tell us where your lot is and we’ll check access before quoting.

Is Lanipuna Gardens treated differently from Leilani?

The septic rules are the same, and both are in lava zone 1. The difference is access, since the county said in 2023 that the Lauone Street stretch to Lanipuna Gardens would not be restored.

How big a system does a one-acre Leilani lot need?

Size depends on bedrooms, not acreage. A one-acre lot clears the 10,000 square foot minimum easily.