Upcountry views come with slopes. Building on the side of Haleakalā means moving a lot of earth, holding it in place and managing the water that rushes downhill in a big storm.
Cut, fill and the house pad
Most sloped lots get a level pad by cutting into the uphill side and filling the downhill side. Fill must be placed in layers and compacted, or it settles and cracks foundations. On larger cuts or fills, expect a soils or geotechnical engineer to set the requirements. Moving that much earth also triggers a county grading permit. See the permit guide.
Retaining walls
Retaining walls hold the cut and the fill. Maui County requires a building permit to build any structure. Taller or load-bearing walls generally need an engineered design, so ask your designer early. Local contractors often build boulder walls from the basalt they dig up; see why lava rock matters.
Water is the real enemy
The March 2026 Kona low showed what Upcountry runoff can do. Maui Now reported nearly 50 inches of rain over three days at Haleakalā's summit and parts of Kula. Kula residents told Hawaiʻi Public Radio that an undersized culvert helped turn a stream into a torrent that tore through properties and Polipoli Road.
On a slope, plan for:
- Interceptor swales uphill of the house to catch and redirect sheet flow.
- Properly sized culverts under driveways.
- Drainage behind retaining walls (gravel and perforated pipe) so water pressure doesn't push them over.
- Not sending your water onto the neighbors. Changing drainage onto abutting properties is one of the things that takes a job out of permit-exempt territory.
See our drainage guide for Kona storms.
Wastewater on a slope
Steep ground complicates septic leach fields. State law allows the Health Department to grant exemptions or approve other systems for reasons including steep topography. See septic vs. aerobic systems.
Find Upcountry excavation contractors in our Upcountry directory.