Septic Installation & Cesspool Conversion in Hakalau
We install septic systems and convert cesspools in Hakalau, about 40 minutes from our equipment yard in Keaau. Hakalau is built around a deep gulch. The Highway 19 bridge over Hakalau Stream stands 261 feet above the stream bed, and the old sugar mill sat far below it, down by the bay. For septic work, almost everything here comes back to slope, stream setbacks and getting equipment in.
Hakalau facts that matter for septic
- Census: Hakalau isn’t listed as a Census designated place in the state’s 2020 tables, so there is no separate population or housing count for it. We won’t guess one.
- Location: The Hakalau Stream Bridge is about 13 miles north of Hilo, near mile marker 15.3 on Highway 19.
- The gulch: The bridge is 775 feet long and 261 feet above the stream.
- Soils: The USDA maps the ash soils of this coast as the Hilo series below about 1,100 feet and the Kaiwiki series above it, both 44 to more than 60 inches deep over old Mauna Kea lava.
- Rainfall: The Hilo series forms under 130 to more than 200 inches of rain a year, and the Kaiwiki series under 200 or more.
- Newer lots: The Hakalau Plantation Village subdivision was laid out in 2004 on former Up Camp land, with houses on 19 of its 22 lots. Former cane land around Hakalau was also divided into ten-acre lots around 2000.
From mill town to house lots
Hakalau Plantation grew through the 1880s with workers from China, Portugal and Japan, followed by Korea and Spain. In 1911 the Hilo Railroad pushed its line across Hakalau Gulch on a steel trestle. Then on April 1, 1946, the tsunami struck. The plantation’s own report says the wave almost completely destroyed the mill’s boiling house and machine shop and carried away the storage flume and its trestle across the gulch. The mill was rebuilt and restarted in March 1947. The railroad’s steel bridge over Hakalau Stream survived, but the line never ran again because the tsunami had wrecked other bridges. That trestle was widened into the highway bridge, which opened to cars in 1953. Ten houses at Up Camp were moved to make room for that highway.
Hakalau merged into Pepeekeo Sugar in 1963, and its mill closed in the 1970s as cane went to an expanded Pepeekeo mill instead. The last cane harvest on old Hakalau land was in 1994. Most homes and buildings below the highway were later torn down to make way for oceanside estates.
What that leaves for homeowners is a mix: a few surviving plantation-era buildings, larger lots carved out of cane fields, and the newer homes in Plantation Village. Each one needs a different conversation about septic.
Slope rules on gulch country
The ground here falls hard toward Hakalau Stream and the ocean, and the USDA notes this soil can reach 200 percent slope in gulch areas. Under HAR 11-62, trenches can’t be built on ground over 12 percent, and beds can’t go over 8 percent. Steeper lots can use a seepage pit, which needs 9 feet of clearance to the property line. Disposal areas also need 50 feet of separation from streams and the shoreline. Near the gulch rim, that buffer can rule out more ground than the slope does.
The ash soil itself is usually workable. It is well drained and deep, and the soil replacement system required on fractured lava in Puna often isn’t needed here, though only the engineer’s 5-foot soil profile and percolation test can confirm that for a lot. The bigger risk is the slope above and below. The U.S. Geological Survey has found that ash slopes near Hilo stand steep when undisturbed but are prone to landsliding during earthquakes, so we keep cuts and spoil piles away from gulch edges.
What Hakalau owners typically need
- New systems on ten-acre lots. Larger parcels have room to find a flat bench for a leach field. Lots created after August 30, 1991 must have 10,000 square feet per system, which a ten-acre parcel easily meets.
- Plantation Village homes. These houses went up from 2006 on, before the 2016 statewide ban on new cesspools. Owners should confirm what system their house actually has before planning an addition.
- Older plantation buildings that may still sit on a cesspool, often near steep ground.
Getting a crew to Hakalau
We run from Keaau through Hilo and up Highway 19, about 40 minutes without delays. The state Department of Transportation is rehabilitating the Hakalau Stream Bridge. Foundation repairs started in September 2025 with a 45 mph limit and possible lane closures, lead soil removal under the bridge began in June 2026, and the full rehabilitation is estimated at $78 million. A 2024 assessment projected construction lasting into late 2028. We factor bridge work into delivery timing. Some lots below the bridge are reached by the Old Mamalahoa Highway and Old Mill Access Road, which the state plans to resurface after construction, and we check those routes for trailer access before scheduling.
Deadlines and funding
Act 125 sets January 1, 2050 as the date every cesspool in the state must be gone. Hakalau was not one of the five Hawaii Island areas in the state’s 2017 priority report. To see how your parcel rates, our priority map guide shows how to use the University of Hawaii tool. We don’t know of any county sewer in Hakalau, but confirm with the County Department of Environmental Management for your parcel.
Steep ground, gulch setbacks and the longer haul from Keaau can push a Hakalau job toward the higher end. Our conversion cost guide explains the range. Very-low-income owners can check eligibility for USDA Section 504 repair loans and grants at the USDA office in Hilo.
Neighboring areas
South along Highway 19, Honomu has no county sewer at all, and Pepeekeo is where Hakalau’s cane went after 1963. Closer to town, see Wainaku, Paukaa and Papaikou, or our Hilo septic services page for the full district.
Before you plan anything in the gulch
Hakalau lots are rarely simple. We can walk the property, check the slope and the stream setback, and work out how to get equipment in before the engineer draws anything. Request a free estimate
Frequently Asked Questions
Is there county sewer in Hakalau?
We haven’t found any record of county sewer in Hakalau. Ask the County Department of Environmental Management with your tax map key to confirm before you plan.
Will the Hakalau bridge work delay my septic install?
It can affect timing. The highway has had reduced speeds and possible lane closures at the bridge, and the rehabilitation is projected to run for a few years. We plan tank deliveries around it.
My ten-acre lot slopes toward Hakalau Stream. Where can the system go?
Start by measuring 50 feet back from the stream bank, since nothing can go inside that line. On a big lot there is often a gentler bench farther up where trenches fit. If every candidate spot is over the 12 percent trench limit, the engineer can design a seepage pit.
Does septic in Hakalau need the soil replacement used in Puna?
Usually not. That requirement applies to fractured lava. Hakalau is mostly deep ash soil, but the engineer’s soil profile decides.
I live in Hakalau Plantation Village. Do I have a cesspool?
The village homes were built starting in 2006, so check your permit records with the county to see what was installed. If you are adding a bedroom, the Department of Health will review the system as part of the building permit.
Why is Hakalau a more expensive place to install septic?
Steep ground, gulch setbacks and the long haul from Keaau all add excavation time and trucking. Each lot is different, so the estimate comes after a site visit.