Septic Installation & Cesspool Conversion in Ainaloa
We install septic systems and convert cesspools in Ainaloa, about 10 minutes from our equipment yard in Keaau. What sets septic in Ainaloa apart from the big acreage subdivisions around it is lot size. Most lots here are about a quarter acre, so the question isn’t only how to get through the lava. It’s also how to fit a legal system on a small lot with a house already on it.
Ainaloa Facts That Affect Your System
- Population: 3,609 residents in 1,269 households in the 2020 Census, up from 2,965 in 2010. That’s growth of more than 20 percent in a decade.
- Density: about 1,820 people per square mile in 2020, packed into roughly 2 square miles.
- Housing units: 1,165 in the 2010 Census.
- Lots: mostly around a quarter acre (about 10,900 square feet), with two lots between each side street, according to a local real estate guide.
- Elevation: about 705 feet.
- Neighbors: Hawaiian Acres to the west, Orchidland Estates to the north and Hawaiian Paradise Park to the northeast. Hilo is about 15 miles north.
- Water: most homes rely on rain catchment.
- Lava hazard zone: Zone 3 at two Ainaloa locations we looked up in the State’s copy of the USGS lava zone map.
- Ground: Ainaloa sits on the Ailaau lava flows, pahoehoe that erupted from Kilauea’s summit starting in the early 1400s, according to USGS.
Quarter-Acre Lots and the 10,000 Square Foot Rule
State rules (HAR 11-62) call for 10,000 square feet of land per wastewater system. A true quarter acre is about 10,890 square feet, so a typical Ainaloa lot clears that line, but only just. Lot sizes vary, so check yours.
Older lots get a pass: the land-area minimum doesn’t apply to parcels recorded before August 30, 1991. Puna’s subdivision lots were created between 1958 and 1973, according to a history of the district’s subdivisions, so many older Ainaloa lots may qualify. Your engineer confirms the recording date for your parcel.
On a quarter acre, the bigger squeeze is usually the setbacks, not the land area:
- 5 feet from the tank and disposal area to any building
- 5 feet to the property line, or 9 feet for a seepage pit
Your engineer also has to work around the catchment tank. Put a house, a carport and a catchment tank on 10,900 square feet and the open ground left for a leach field can be small. That’s why we often look at the layout before anything else.
Breaking Through Ailaau Pahoehoe
The Ailaau eruption covered about 166 square miles of Puna with pahoehoe. USGS names Ainaloa among the communities built mainly or entirely on it. Most of that lava moved through an extensive network of lava tubes, including Kazumura Cave, which runs about 25 miles from near the summit toward the coast.
For septic work that means fractured rock close to the surface. On fractured lava, the state’s wastewater rule calls for a soil replacement system, meaning the rock under the leach field is dug out and replaced with fill that keeps a minimum of 3 feet between the effluent and groundwater. A registered engineer perc-tests the lot and digs a 5-foot profile before anything is drawn.
On a small lot, rock removal has to be planned around what’s already there. We may have to stage the excavator in the street or use a smaller machine near the house. Across Hawaii a typical conversion lands somewhere from $20,000 to $50,000, and Ainaloa’s rock tends to push it higher. Our guide to conversion costs breaks it down.
What Ainaloa Homeowners Usually Need
Ainaloa added more than 600 residents between 2010 and 2020, and growth on small lots creates a few common situations:
- Building on a vacant lot. No new cesspool has been allowed in Hawaii since March 21, 2016, so a new house needs an approved septic or aerobic system, and the Health Department’s sign-off on that design comes before the county issues your building permit. See our page on new home septic requirements.
- Adding rooms. Health rules treat a room of 70 square feet or larger as a bedroom, and a permit that adds bedrooms can lead DOH to require an upgrade.
- An aging cesspool. If yours needs pumping every few months, note that DOH can order a conversion once a cesspool is pumped more than twice in a 12-month stretch.
Roads and the Homeowners Association
Ainaloa has two main roads, Ainaloa Boulevard and Ainaloa Drive, running up the hill from Highway 130, with cross streets between them. The lower roads are paved. The Ainaloa Estates homeowners association has charged a mandatory per-lot fee for road work and vegetation clearing, and has aimed to pave a couple more roads each year.
For us, that means a short haul from Keaau and generally easy access off the highway. On unpaved upper streets we plan the tank delivery and the excavator trailer around wet weather. The association also enforces CC&Rs on the appearance of structures, so it’s worth asking whether anything above ground needs its approval.
Ainaloa in the Puna Sewer Study
Here’s something specific to Ainaloa. When the County began studying wastewater service for Puna in 2022, Ainaloa made the short list: it was among ten Puna communities flagged for possible treatment, which fits a dense, small-lot subdivision. Mayor Roth accepted the final environmental impact statement in October 2023 without naming a preferred option in his letter, and the County said at the outset that it had no funding lined up yet.
Bottom line: sewer is not on the ground in Ainaloa today, and the County said in 2022 that it provides no wastewater service in the Puna project area. Ask the Department of Environmental Management for the latest before you design. The state’s cutoff for every remaining cesspool is still January 1, 2050. Our Act 125 explainer walks through the law.
On financing: a very-low-income household can apply for a USDA Section 504 repair loan (as much as $40,000, 1 percent interest, 20-year term), and owners aged 62 or older can also apply for a grant of as much as $10,000. Ask the Hilo USDA office about eligibility. A new state loan program created by Act 204 should open through the Hawaii Green Infrastructure Authority in late 2026.
Other Upper Puna Subdivisions We Serve
We also serve Orchidland Estates, Hawaiian Acres, Hawaiian Paradise Park and Hawaiian Beaches & Shores. For the district as a whole, start at Puna septic services.
Talk to Us About Your Ainaloa Lot
Send us your street, your lot size and where your catchment tank sits. We’ll tell you what fits and what the rock is likely to cost you. Request a free estimate
Frequently Asked Questions
My Ainaloa lot is a quarter acre. Is that big enough for a septic system?
Usually. A quarter acre is about 10,890 square feet, just over the 10,000 square foot minimum, and the minimum doesn’t apply to a lot recorded before the August 30, 1991 cutoff. Setbacks to the house, lot lines and catchment tank are often the tighter limit.
Will my catchment tank get in the way?
It can. On a small lot the tank, the house and the disposal area all compete for the same space. Your engineer lays out the system to keep it clear of your water supply.
Is Ainaloa getting county sewer?
Ainaloa was named in the County’s Puna wastewater study, but no project has been built. The County said in 2022 it provides no wastewater service in the Puna project area. Check with DEM for your parcel.
Do Ainaloa’s unpaved roads slow down a job?
Sometimes. The lower roads are paved and the association has been paving more. On gravel streets, we schedule heavy deliveries around the weather.
What lava zone is Ainaloa in?
The points we checked on the USGS hazard map came back Zone 3. Look up your own parcel, since lenders and insurers go by the exact address.