Septic Installation & Cesspool Conversion in the Puna District

We install septic systems and convert cesspools all over the Puna District, and our excavators are based in Keaau, at Puna’s northern edge. Puna is a big district, though, and a system that works on a lot in Fern Forest can look nothing like the one a lot in Hawaiian Beaches needs.

This page covers what Puna’s communities have in common: no county sewer, thin soil, heavy rain, and thousands of lots laid out long before anyone planned for their wastewater. Each community also has its own page, linked below.

Puna by the Numbers

  • 51,704 residents in the 2020 Census, up from 5,154 in 1970. Puna now has slightly more people than South Hilo (51,551).
  • About 500 square miles, slightly smaller than Kauai.
  • More than 52,500 subdivision lots were created in Puna between 1958 and 1973, according to county records cited by Civil Beat.
  • Housing: the Census Bureau’s two Puna-area county divisions, Keaau-Mountain View and Pahoa-Kalapana, counted about 16,975 and 5,307 housing units in the 2020 to 2024 American Community Survey.
  • About 16,000 cesspools in Puna, which has no county wastewater service.
  • About 44% of Puna’s subdivisions sit in lava hazard zones 1 and 2, according to a 2008 county report.

Why Puna Homes Handle Their Own Wastewater

Puna has no county sewer. Most homes also have no county water line, so families depend on rain catchment or private wells. A house here has to treat its own wastewater on its own lot, and in older homes that has usually meant a cesspool.

The county has studied this. In October 2023 the mayor accepted a programmatic environmental impact statement on adding wastewater service to Puna. It looked at options ranging from leaving everything to property owners, to small plants in Keaau, Hawaiian Paradise Park, Volcano and possibly Pahoa, to one regional plant in Keaau, to piping flow to the Hilo treatment plant. Even under the centralized options, properties outside the planned service areas would keep using individual systems. The study assumed construction contracts would run from about 2027 to 2047, with work finishing around 2052. That’s after the state’s cesspool deadline.

For nearly every Puna lot, the practical plan is an on-site system: a septic tank with a leach field or soil replacement bed, or an aerobic treatment unit where the site calls for one. If you want to know whether a future project could reach your street, ask the county Department of Environmental Management.

Lava Rock and the Rainfall Gradient

The soil surveys show how little dirt there is in Puna. The Keaukaha soil series covers about 50,000 acres of the island and sits 2 to 20 inches deep over pahoehoe. The Opihikao series in lower Puna is only 2 to 10 inches deep. Around Kurtistown the Olaa series is deeper, with 20 to 39 inches of volcanic ash over aa. That’s still shallow by mainland standards.

The rock under that thin layer is fractured, and water moves through the cracks fast. State rules respond directly: on fractured lava, the treatment bed has to be built from replacement soil and sit a minimum of 3 feet above groundwater. In practice that means breaking or excavating rock, bringing in suitable fill and building the treatment bed in it. That rock work drives much of the cost.

Rainfall changes a lot from the highway corridor down to the coast. Mountain View averages about 185 inches a year. The Opihikao soils, mapped in lower Puna near Highway 130 and Old Kalapana Road, form under roughly 60 to 120 inches. Up at Volcano, the park headquarters averages about 96 inches. Storms add to that: during the March 2026 rain event the Glenwood gauge logged more than 21 inches in two weeks. Wet upper Puna sites take careful scheduling and good drainage around the bed. Lower Puna has some of the thinnest mapped soils in the district, so rock work drives the cost there.

The Subdivision Boom and What It Left Behind

Starting in 1959, a wave of large nonconforming subdivisions was carved out of Puna. Leilani Estates, formed in 1964, is one of them. Lots were sold before roads, water or wastewater were planned. Hundreds of miles of Puna road still have no agency that claims responsibility for them.

That history explains most Puna septic jobs:

  • Older homes on cesspools built before 2016, when new cesspools were banned statewide.
  • Owner-builder new construction on vacant lots, which has to start with an engineered septic design.
  • Ohana units and additions, since new bedrooms on a permit give DOH grounds to order an upgrade.
  • Lots with rough access, where a private or unclaimed road decides what equipment can reach the site.

Owner-builders should settle bedroom count early, because it drives system size. Our new home septic guide explains the sizing rules.

The Keaau Priority Area and the 2050 Deadline

The Department of Health’s 2017 report put about 9,300 Puna cesspools into the Keaau priority area. It was rated Priority 2 because of the potential impact on drinking water. The area covers 91 square miles along a 4.3-mile-wide groundwater flow path on Kilauea’s east slope, where public water isn’t available and many families drink from private wells. The same report named a small Kapoho area, about 220 cesspools, for its effect on the Waiopae tide pools.

Puna’s priority listing carries no special due date. The statewide cutoff of January 1, 2050 applies here like anywhere else, though DOH may order earlier action after a bedroom-adding permit or a run of pump-outs and overflows. Our priority map guide shows how to look up a specific parcel in the University of Hawaii prioritization tool.

Money is the hard part for many Puna families. Statewide, conversions typically land between $20,000 and $50,000, and rocky sites trend high. There’s no open state grant today. A state loan fund created by Act 204 should open around the end of 2026, and low-income rural owners may qualify for USDA Section 504 help. Details are on our funding page.

Highway 11 Corridor

Highway 11 climbs from Keaau toward Volcano through some of Puna’s wettest country.

  • Keaau is where our excavators are based. The Highway 11 and Highway 130 junction is here, and the Olaa sugar mill operated from 1900 to 1982.
  • Kurtistown is the type location for the Olaa soil series, with 20 to 39 inches of ash over aa, deeper than the soils mapped near the coast. It had 2,515 residents in 2020.
  • Mountain View, at about 1,434 feet, averages roughly 185 inches of rain a year. That much rain shapes both the design and the work schedule.
  • Hawaiian Acres spreads across 19.4 square miles south of Kurtistown, bordering the Puna Forest Reserve, with 1,569 housing units in 2020.
  • Fern Acres sits around 1,532 feet, about 17 miles south of Hilo, with 858 housing units in 2020.
  • Eden Roc lies about 3 miles south of Highway 11 at roughly 1,788 feet, so access planning starts at the highway turnoff.
  • Fern Forest is the highest of these subdivisions, around 2,260 feet, with 575 housing units in 2020.

Highway 130 Corridor

Highway 130 runs from Keaau down toward Pahoa and carries most of Puna’s commuter traffic.

  • Hawaiian Paradise Park is Puna’s largest community, with 14,957 residents and 5,745 housing units in the 2020 Census.
  • Orchidland Estates had 3,165 residents and 1,178 households in 2020. The Census lists it as Orchidlands Estates.
  • Ainaloa borders Hawaiian Paradise Park, Orchidland and Hawaiian Acres, and had 3,609 residents in 2020.
  • Pahoa sits at about 655 feet. The 2014 lava flow claimed a home and stopped just short of Highway 130.

Lower Puna and the Coast

Lower Puna has the thinnest soils and the most recent lava history in the district.

  • Hawaiian Beaches & Shores runs from Highway 130 to the ocean, at about 256 feet elevation, with 1,783 housing units in 2020. Near-shore lots there need extra care with the 50-foot shoreline setback.
  • Nanawale Estates sits around 420 feet, between Hawaiian Beaches and the Nanawale Forest Reserve.
  • Leilani Estates & Lanipuna Gardens took the worst of 2018: 14 of the 24 fissures opened inside Leilani, and about 200 homes there were destroyed.
  • Kalapana area was largely buried by lava in 1990, and only 167 people lived in the Kalapana census area in 2020.

Up the Hill to Volcano

Above Fern Forest, Highway 11 reaches Volcano Village, at about 3,750 feet on the edge of Hawaii Volcanoes National Park. It gets about half the rain Mountain View does and sits near the rim of Kilauea’s summit caldera. Nearby Glenwood and the Volcano Golf and Country Club area have their own pages.

Planning a Puna Project

A good Puna project starts with the lot: how deep the soil is, where the rock fractures, how a truck gets in, and how many bedrooms the system has to serve. We can walk your property with you, work with your engineer on the design, and handle the excavation, rock work and installation. Request a free estimate

Frequently Asked Questions

Does any part of Puna have county sewer?

Puna has no county wastewater service today. The county accepted a programmatic environmental study in 2023 that weighs several ways to add service, but construction under that study’s assumptions would run into the 2050s. For a specific address, confirm with the county Department of Environmental Management.

Can I keep my cesspool and wait for the county?

The state cutoff is 2050, and the county’s own construction timeline runs past it. Waiting also doesn’t protect you from an earlier DOH order after a remodel or repeated failures. Most owners are better off planning their own system.

Why are Puna septic systems more expensive than ones on the mainland?

Most Puna lots have a few inches to a couple of feet of soil over fractured lava. State rules then call for a soil replacement system, which means rock excavation and imported fill. Remote lots and rough roads add trucking time.

I’m on catchment, not a well. Does the Keaau priority area matter to me?

Priority status doesn’t change your deadline. It matters because many of your neighbors drink from private wells. In DOH’s 2017 study, a quarter of the domestic wells sampled in the Keaau area tested positive for wastewater indicator bacteria.

My road isn’t maintained by the county. Can you still get equipment in?

Usually, but we need to see it first. Many Puna subdivisions run on private or unclaimed roads, so we check the width, surface, grades and any gates before we plan what equipment to bring.

Will adding an ohana unit force me to replace my cesspool?

Possibly. New bedrooms on a permit give DOH the option to require the upgrade then. One system tops out at five bedrooms, so a big main house plus an ohana may need two.