Septic Installation & Cesspool Conversion in Pahoa

We install septic systems and convert cesspools in Pahoa, roughly 20 minutes down Highway 130 from our equipment yard in Keaau. Pahoa is the old town of lower Puna, so septic in Pahoa covers more than houses. It includes commercial buildings along the old main street, homes on small in-town lots, and owners who still remember lava stopping at the edge of town in 2014.

Pahoa at a Glance

  • People: 924 residents in 305 households in the 2020 Census, nearly flat from 945 in 2010. The census area covers only about 2.2 square miles around the town.
  • Homes: the 2010 Census counted 356 housing units, the most recent unit count we could find for the town.
  • Elevation: about 655 feet.
  • Lava hazard zone: Zone 2 for the spot in town we checked, using the 1991 USGS hazard zones the State GIS office hosts.
  • Sewer: in its 2022 environmental impact statement notice, the County said it provides no wastewater collection or treatment in the Puna project area. Most residents use individual systems such as cesspools and aerobic units.
  • Lava history: most of the 1840 eruption centered just southeast of town, and the June 27th flow reached the edge of Pahoa in 2014.

Old Town Lots and What They Mean for a System

Pahoa started out as a mill town. The Hawaiian Mahogany Company began cutting there in 1907, and logs were milled in town and shipped out as railroad ties for the Santa Fe Railroad. The mill and its rail spur sat near where the Akebono Theater stands today. A 1913 fire destroyed the main mill, and the operation closed in 1916.

Main Street (Pahoa Village Road), the old highway before the bypass, still has much of its plantation-era street wall, and most of its buildings are now in commercial or civic use. For septic work, that history shows up in a few ways:

  • Small lots. The land-area rule (10,000 square feet per system) is waived for any lot on record before August 30, 1991, and your engineer will check when yours was recorded. A waived lot still needs room to keep the tank and disposal area 5 feet from structures and the lot boundary, or 9 feet for a seepage pit.
  • Buildings near the line. Older storefronts and homes close to a lot edge can push the system to the back of the parcel and limit where an excavator and tank delivery fit. We walk the access on the first visit.
  • Lost cesspools. On an older property, nobody may know exactly where the cesspool is. We locate it before design starts.

Working Through the Rock

Lower Puna is built on lava, not deep soil. USDA soil scientists map a soil they call Opihikao across the Puna district, and it’s thin: typically 2 to 10 inches of organic material over pahoehoe. On cracked lava the leach field must be a soil replacement system, built by trenching out rock and filling back with material that gives effluent 3 feet or more of travel above groundwater. A percolation test and a 5-foot soil log by your engineer come first.

Breaking rock in a tight town yard is slow work. Most Hawaii conversions cost between $20,000 and $50,000, and a cramped lot on rock is a top-of-the-range job. Our cesspool conversion cost guide explains where the money goes.

Shops, Cafes and the Large Capacity Rule

Many of Pahoa’s older buildings serve the public, and that brings a federal rule into play. A cesspool that can serve 20 or more people a day counts as a Large Capacity Cesspool, and those have been banned since 2005. In 2024 the EPA ordered a retreat center with a Pahoa address to close a cesspool serving a campground restroom by July 2025.

If you own a cafe, shop or rental building on a cesspool, the 2050 deadline may not be the one that matters. Ask an engineer whether your building falls under the federal rule.

When Lava Came to Town

The June 27th flow started on Kilauea’s East Rift Zone in 2014. In late October it crossed Cemetery Road, moved through the Pahoa Japanese Cemetery, and stalled about 510 feet from Pahoa Village Road, according to USGS. On November 10 it destroyed a home upslope of the flow front, the only house lost in the crisis. The next day it pushed through the fence of the Pahoa transfer station. Another lobe stopped about a third of a mile from Pahoa Marketplace on December 30, 2014.

At the time, Highway 130 was described as the only route in and out of Pahoa and the rest of lower Puna. Four years later, during the 2018 eruption in nearby Leilani Estates, Pahoa was the main shelter site. On one day in late May 2018, 215 of the 236 people in shelters were at Pahoa.

The practical lesson: every truck, excavator and tank reaches town on Highway 130.

Deadlines, Sewer Plans and Funding

Act 125 sets one statewide finish line: no cesspools in use after 2049, whatever their priority color. The Department of Health has discretion to require one sooner, for example after a permit for added bedrooms, or when a cesspool needs pumping more than twice in 12 months or spills more than once in that time. Our Act 125 explainer covers the details.

Pahoa did come up in the County’s Puna wastewater planning: scoping in 2022 put it on a list of ten communities, and one of the final EIS alternatives drew a service area and plant around the town. The Mayor’s October 2023 acceptance of that EIS stopped short of picking any alternative. Before you design anything, ask the Department of Environmental Management whether sewer is planned for your street.

If cost is the obstacle, talk to USDA Rural Development in Hilo about Section 504: 1 percent loans of as much as $40,000 over 20 years for very-low-income homeowners, plus grants of as much as $10,000 for those 62 and older. Eligibility rules apply. Hawaii’s own conversion loan fund (Act 204, run by HGIA) is due to launch late in 2026.

Around Pahoa

We also work in Nanawale Estates, Hawaiian Beaches & Shores, Leilani Estates and the Kalapana area. For the whole district, see Puna septic services.

Get a Pahoa Estimate

Send us your address and tell us whether it’s a home or a commercial building. We’ll look at the lot and the rock and tell you plainly what the job involves. Request a free estimate

Frequently Asked Questions

Is Pahoa on county sewer?

The County’s 2022 EIS notice said it provides no wastewater collection or treatment in the Puna project area, which includes Pahoa. The County has studied future service, so confirm the status of your parcel with the Department of Environmental Management.

My Pahoa lot is under 10,000 square feet. Can I still get a septic system?

Often, yes. A lot recorded before August 30, 1991 isn’t held to the 10,000 square foot rule. Setbacks still apply, so the lot’s shape decides where the tank and disposal area fit.

I run a business on Pahoa Village Road with a cesspool. Does the federal rule apply?

It might. A cesspool that can serve 20 or more people a day is a Large Capacity Cesspool, banned since 2005. Have an engineer review your building and its daily use.

Did the 2014 lava flow change Pahoa’s hazard zone?

The 1991 USGS zone layer still puts the in-town point we checked in Zone 2. Ask your lender or insurer how they treat your specific address.

Should I wait for a Pahoa sewer before converting?

When the EIS came out, funding had not been secured, and its timeline spread construction from about 2027 to 2052. If DEM can’t give you a date for your street, a code-compliant system now is usually the safer bet, especially if DOH has already flagged your cesspool.

Can I add an ohana unit on my existing Pahoa cesspool?

Not without DOH review. Adding sleeping space on a permit can lead to a required upgrade, and DOH counts any room from 70 square feet up as a bedroom. Our step-by-step conversion guide shows the order.