OSDS (Onsite Sewage Disposal System)
OSDS stands for Onsite Sewage Disposal System — the umbrella term for a parcel's own wastewater system where there is no sewer connection. It covers cesspools, septic systems, and aerobic treatment units.
Whether a parcel is on sewer or relies on an OSDS drives a real difference in development cost and permitting. Where an OSDS is required, its type matters: a legacy cesspool must eventually be converted under Act 125, a septic system depends on soils and separation to groundwater under HAR §11-62, and an aerobic unit may be required where a conventional system won't meet the standard.
Knowing a parcel's wastewater path — sewer, septic, or cesspool-on-record — up front tells you whether a ground-disturbing conversion is coming and roughly how invasive it will be, which is exactly the kind of cost a buyer wants surfaced before closing.
An Onsite Sewage Disposal System — a parcel's own wastewater system where there's no sewer: a cesspool, septic system, or aerobic treatment unit.
This is a plain-language reference, not legal advice. KILO is a pre-development screening tool, not a system of record — confirm any determination with the agency of jurisdiction.