NZ on-site wastewater (septic) + greywater installed costs (2026 web synthesis)
Resolves RT_278 (septic cost cell); advances RT_211 (greywater cost + reuse fraction)
No NZ government/academic source publishes installed costs — pricing is from NZ industry installers → indicative, data_quality medium. Septic verdict confirmed (low risk); greywater equipment prices spot-confirmed (WCTNZ), but the installed-total and the year-round reuse % are synthesis estimates (flagged). The reuse fraction directly informs the engine’s interim
GREYWATER_FRAC = 0.30.
Summary
Fully-installed NZ costs for the two D03 sanitation/water cost cells. Septic: ~NZD 15,000 fully installed (range 10,000–20,000) for a conventional single-household septic tank + drain field — but most councils now require advanced/aerated treatment (AWTS) for new builds at NZD 15,000–30,000+ (secondary + UV 25,000–40,000), so the higher band is realistic for a new community. Greywater: WCTNZ equipment (ex-GST) runs NZD 1,130 (gravity diverter) to 1,913 (Nature Clear treatment unit), with installed totals ~NZD 3,000–5,000 (diversion) or 5,000–8,000+ (full treatment + disinfection). Greywater is ~68% of the gross residential stream, but the realistic year-round reusable fraction is ~25–35% (untreated diverter → seasonal sub-surface irrigation only; only treated+disinfected supports year-round toilet flushing) — a synthesis estimate to validate.
Key claims
- claim: "SEPTIC — conventional (RT_278). ~NZD 15,000 fully installed (range 10,000–20,000) for a conventional single-household septic tank + drain field. Itemised: concrete tank NZD 4,000–12,000 (by size) + excavation/install 1,000–4,000 + drain field + consent NZD 600–1,500 +GST. Pump-out NZD 300–600 every 3–5 years. Governed by AS/NZS 1547:2012 (land application) + AS/NZS 1546.1 (septic tanks); PE up to ~10 persons; highly site-dependent (soil/percolation, slope). Defensible model band NZD 15,000–20,000 conventional per household."
source_location: "Part A; Hamilton Concrete Co. (tank prices), Septic Safe Solutions NZ (bands), building.govt.nz / BRANZ Level (framework)"
- claim: "SEPTIC — advanced/AWTS (RT_278, likely the realistic band for a new community). Most councils now REQUIRE advanced/aerated treatment (AWTS) for new builds — NZD 15,000–30,000+; secondary + UV NZD 25,000–40,000 +GST. Defensible model band NZD 20,000–30,000 advanced per household. This is the band that pairs with the CR_046 finding that a 5–100 HH settlement usually exceeds single-site permitted wastewater thresholds (RMA s15 discharge consent; Canterbury LWRP Rule 5.8 <=2,000 L/day + site >=4 ha)."
source_location: "Part A; Septic Safe Solutions NZ (AWTS band), Waterflow NZ (secondary+UV band)"
- claim: "GREYWATER — equipment + installed cost (RT_211). WCTNZ equipment (ex-GST, spot-confirmed live): gravity diverter NZD 1,130; pumped diverter NZD 1,281; Nature Clear treatment unit NZD 1,913. Installed totals (ESTIMATED): ~NZD 3,000–5,000 (diversion) / 5,000–8,000+ (full treatment + disinfection, needs a certifying drainlayer). The equipment prices are sourced; the installed totals are synthesis estimates."
source_location: "Part B; WCTNZ product page (prices); installed totals stated as estimates"
- claim: "GREYWATER — reuse fraction (RT_211, informs engine GREYWATER_FRAC). Greywater is 68% of residential use (160 L/person/day, Kapiti Coast DC via BRANZ Level) — but that is the GROSS stream. Realistic year-round reusable fraction ~25–35% of household water (untreated diverter → seasonal sub-surface irrigation only; only treated+disinfected → year-round toilet flushing). WARNING: the 25–35% year-round figure is a SYNTHESIS ESTIMATE, not a sourced NZ number — validate. The engine's interim GREYWATER_FRAC = 0.30 sits inside this band but is not yet primary-sourced."
source_location: "Part B; Kapiti Coast DC 68% via BRANZ Level; 25–35% flagged as estimate"Neobiome Intelligence relevance
Resolves RT_278 — fills the D03 septic sanitation cost cell (conventional ~NZD 15–20k; advanced/AWTS ~NZD 20–30k, the realistic band since councils require it for new builds). This pairs with CR_046 (a community wastewater discharge usually needs RMA s15 consent; Canterbury Rule 5.8 ≤2,000 L/day + ≥4 ha) and offers the costed alternative to composting toilets (RT_223). Advances RT_211 — gives greywater_recycling its first NZ cost data (equipment sourced; installed-total + reuse % soft) and directly informs the engine’s interim GREYWATER_FRAC = 0.30: the 25–35% year-round reuse band brackets 0.30, so 0.30 is defensible but still an estimate, not primary-sourced → RT_211 stays partly open. The WCTNZ prices are the sourced anchor; the installed totals and reuse % need firming before they harden a model cell. See D03.
Retrieval provenance
AI-prepared via WebSearch + WebFetch, 2026-06-20. No NZ government/academic source publishes installed costs → industry-installer pricing, indicative/medium. Sourced: WCTNZ greywater equipment prices (spot-confirmed live); itemised septic tank prices (Hamilton Concrete Co.). Estimates (weakest): greywater installed totals; the 25–35% year-round reuse fraction. Values AI-extracted; re-confirm against the live installer pages before applying to a model cell.
Research targets
Research gaps
- RT_211 stays partly open: a sourced NZ greywater installed-total and a measured year-round reuse fraction (the 25–35% / engine 0.30 is currently an estimate) — BRANZ Bulletin BU665 (paywalled) is the authoritative spec.
Connections
Links to
Technologies (1): Greywater Recycling
EDT domains (1): D03: Water, Waste & Circular Systems
Sources (1): CR_046
Referenced by
Sources (4): OT_110 · OT_111 · OT_124 · URL_026
EDT domains (1): D03: Water, Waste & Circular Systems
Technologies (1): Greywater Recycling