Source
https://www.earthsong.org.nz/resources/documents — original source (opens in a new tab; the file is not redistributed)
Primary document: Infrastructure Auckland Grant — Final Inspection report (23 July 2008) + cost spreadsheet received from Robin Allison (Earthsong), 18 July 2008.
Summary
The closeout document for Earthsong Eco-Neighbourhood’s 2001 Infrastructure Auckland (IA) stormwater grant: an independent final-inspection letter (23 July 2008) plus a three-page itemised cost spreadsheet supplied by an interviewee. It records the actual audited cost of Earthsong’s water-sensitive-design infrastructure — six communal rainwater tanks with pumps and dual-reticulation to toilets, swales, raingardens, a pond, porous paving and landscaping — built progressively between 2002 and 2008. It is the first primary, itemised, built-and-audited NZ community water-system cost in the corpus, and the costed counterpart to the qualitative interviewee account in Interview VI [INT_006].
Key claims
- Six communal rainwater tanks cost **NZ
101,110.50 incl GST** (89,876 excl GST) in total, invoiced 8 Aug 2002 – 14 Sep 2007, covering tank supply, base prep, burial, pumps, plumbing, electrical and dual-supply piping. [primary spreadsheet §1.00] - The complete water-sensitive-design / stormwater package totalled NZ$663,296 incl GST — tanks, swales & raingardens, porous paving, roading/kerbing, landscaping, plus P&G/margin (12%) and contingency (5%). [primary spreadsheet summary]
- Infrastructure Auckland funded 50% of the grant-eligible works — a final grant payment of **
93,471** against ~186,943 eligible. [final-inspection letter] - Rainwater is reticulated to toilets via dual-plumbing (separate non-potable feed to each unit); mains supplies potable water. [§1.09 + inspection narrative; corroborates Interview VI [INT_006]]
- Derived: ~190,000 L total storage (6 × ~7,000 imp gal) across 32 dwellings → ~
532/m³ fully-installed** (2002–07 NZD) and **~3,160/dwelling. (Calculation:101,110 ÷ 190 m³;101,110 ÷ 32. The IA spec was nominally “5,000 gallon tanks”; the as-built inspection records “7,000 gallon” — volume carries a ±15% uncertainty.)
Neobiome Intelligence relevance
This is the installed-system cost the model’s water-cost side lacked. CR_016 gives the bare HDPE tank shell at 110–135/m³; OT_078 shows a *fully-installed communal system* (burial, pumps, dual-reticulation, electrical, base prep) at **~532/m³** — roughly 4× the shell price. That multiplier is the real driver of a community water-capex line. The per-dwelling figure (3,160 in 2002–07 NZD) cross-checks cleanly against CR_016's ~3,500–6,000/household garden/non-potable range once inflation is applied.
Caveats for model use:
- Vintage — costs are 2002–07 NZD; apply an RBNZ CPI deflator (~×1.6 to 2026) before use → ~
850/m³, ~5,000/dwelling indicative (RT_267). - Scope — this is the water/stormwater grant package only; the document contains no whole-build per-dwelling CapEx, so it does not validate the model’s ~$113k/household total.
- Region/model — Auckland (not the Tasman pilot); a communal shared-tank design, not per-house tanks.
Research targets
Documents to retrieve
- (none — this is itself the primary document)
Research gaps
- RT_267 (gap) — additional NZ datapoints for a fully-installed communal rainwater + dual-reticulation system cost, to triangulate OT_078’s ~
532/m³ (2005) installed multiplier against CR_016's bare-tank ~120/m³; and the CPI deflator to restate 2002–07 → 2026 NZD.
Connections
Links to
Sources (1): CR_016
Referenced by