Septic Installation & Cesspool Conversion in Keaukaha

We install septic systems and convert cesspools in Keaukaha, the coastal community between Hilo Airport and the ocean, about 20 minutes from our equipment yard in Keaau. Keaukaha is a homestead community on Hawaiian Home Lands, it sits right on the shoreline, and recent research has tracked sewage from its cesspools into the water off its beaches. All three shape how wastewater work gets done here.

Keaukaha facts that matter for wastewater

  • Homestead since 1924. On December 16, 1924, 61 Native Hawaiian families became lessees of what was then called the Kuhio Settlement. DHHL describes Keaukaha as the state’s second Hawaiian homestead project, after Kalamaula on Molokai.
  • 488 residential lots in Keaukaha Tract 1, which covers about 345 acres of DHHL land, according to a 2023 study done for DHHL. The tract was once about 621 acres and shrank mainly because of Hilo Airport expansions during World War II and the 1960s.
  • 1,617 residents in the Keaukaha Hawaiian Home Land at the 2020 Census.
  • On the Panaewa flow. USGS says this Mauna Loa flow, about 1,200 years old, underlies the airport and most of Keaukaha.
  • Inside the Hilo Bay priority area, which the Department of Health’s 2017 cesspool report counted at roughly 8,700 cesspools.
  • Priority 1 nearby. A 2025 bill in the Legislature noted that the UH Hawaii Cesspool Prioritization Tool ranks cesspools near Keaukaha at priority level 1, the highest.
  • Rain: Hilo Airport, next door, has a 30-year normal of about 130 inches a year.

What the dye tests showed

In February 2025, UH Hilo researchers published results from two years of dye tracer tests in Keaukaha. They found that sewage from cesspools and from the Hilo wastewater treatment plant reaches coastal waters faster than earlier work had recorded. The dye showed up at the shoreline every time, and the researchers estimated the water moved one to two football fields a day through the ground.

Neighbors had been noticing it for a while. A community odor-reporting tool at Puhi Bay, nicknamed the “Pilau-meter,” helped confirm the sewage. The researchers recommended making Hilo a top priority for cesspool conversion, and the county said it is using the results to help prioritize sewer line expansion in Hilo.

For a homeowner, the takeaway is simple. Near the coast, effluent doesn’t have far to go, and a cesspool gives it no treatment on the way.

Shallow soil, old lava, close to the water

Early homestead accounts describe the ground plainly. The DHHL study quotes early accounts of “shallow soil” good enough for dryland sweet potatoes, and a 1927 homesteader who complained of “too much pahoehoe” near his house.

That shallow soil over Panaewa lava is a hard place to treat wastewater. Statewide, the DOH-backed prioritization report notes that cesspools near the shore face a shallow depth to groundwater. HAR 11-62 requires at least 3 feet of separation between the bottom of the disposal area and groundwater, and on fractured lava it calls for a soil replacement system built in imported fill. Where the separation is hard to get, a raised design or an aerobic treatment unit may be what the engineer specifies. ATUs need a service contract with inspections every six months.

Lots close to the water also have to respect the 50-foot setback to the shoreline and to ponds. Keaukaha has brackish ponds, including Loko Waka, so the engineer will check distances early.

Building on homestead land

The homestead lots are DHHL trust land held by lessees, and the DHHL office sits in the middle of the residential area. If you’re a lessee planning a conversion, an addition or a new home, talk with DHHL early about what they need from you before work starts. We’d rather learn that before we schedule an excavator than after.

The typical projects here:

  • Cesspool conversions on older homestead houses, where the house may be decades old and the cesspool undocumented.
  • Rebuilds and additions, which can trigger a DOH upgrade requirement when bedrooms are added. DOH treats a room of 70 square feet or larger as a bedroom.
  • Ohana units for family, within the limit of five bedrooms and 1,000 gallons a day per system.

Streets and staging

Tract 1 is a grid of paved avenues: Andrews, Baker, Pua and Kauhane run inland from Kalanianaole Street, crossed by streets like Desha, Todd, King and Lyman. Access is generally easier than on a hillside or a cinder road. We still check each lot for a place to stage fill and a path for the excavator past the house, walls and plantings. From Keaau we come in by way of Hilo, so the drive is short.

Sewer plans and the treatment plant

Keaukaha has lived next to the county’s wastewater system for a long time. Ka Wai Ola reported in 2022 that the county moved the main Hilo plant to a site near the airport about 25 years earlier, but a pump station remains in Keaukaha, and the outfall lies about an eighth of a mile off the coast near a beach park. Under a 2024 agreement with the EPA, the county’s Hilo plant project must be complete and operating by July 2035.

Sewer for the homestead has been discussed too. A 2025 House bill, HB1362, proposed $6 million a year for two years for DHHL to expand sewer lines in the Keaukaha homestead, with money for house connections. We could not confirm that it passed. Some streets may already have sewer access, and we don’t state which. Ask the County Department of Environmental Management and DHHL about your lot before you pay for a septic design.

Deadline, priority and paying for it

Priority level 1 does not mean an earlier legal deadline. Every cesspool must be upgraded, converted or connected by January 1, 2050 (Act 125 explained). Look up your parcel on the UH tool using our priority map guide.

For funding, the new state cesspool loan program (Act 204) is slated to launch in late 2026. USDA Section 504 repair loans and grants are run from the Hilo office; check eligibility for your address. Our grants and loans guide has the details.

Other areas near Keaukaha

Have us look at your homestead lot

Send us your address and what you have in mind. We’ll look at how close you are to the water, what the ground looks like, and what sewer and DHHL questions to settle first. Request a free estimate

Frequently Asked Questions

Is Keaukaha getting county sewer?

It has been proposed. A 2025 bill sought state money for DHHL to expand sewer lines in the homestead, but we couldn’t confirm it passed. Ask the county and DHHL about your lot.

Do I need DHHL’s okay to replace my cesspool?

The land is DHHL trust land held under lease, so check with the DHHL office before any major work. They can tell you what they need from a lessee.

My lot is close to the ocean. Does that change the design?

Yes. Systems must stay 50 feet from the shoreline and ponds, and shallow groundwater can rule out a standard field. A soil replacement system or an ATU is common in these conditions.

Keaukaha cesspools are priority 1. Do I have to convert sooner?

No earlier deadline applies. The legal deadline is January 1, 2050. DOH can still require an upgrade earlier, for example when a permit adds bedrooms.

Why is a Keaukaha conversion often more involved than one in town?

Thin soil over old Panaewa lava, shallow groundwater near the coast, and shoreline setbacks all push toward engineered systems with imported fill.

Will the Hilo treatment plant work affect my project?

Not directly. The plant rebuild is a county project. Your own system or sewer hookup is a separate decision that depends on what’s available at your address.