Project 03

WaterOps ANZ

Drinking water · NZ

Runs a drinking-water contamination incident end to end: lab evidence, a versioned rule decision, a boil-water notice with a dual-approval boundary, and a stand-down gate that will not lift on the wrong evidence.

The stand-down gate keyed on lab import time — so samples collected before the contamination could clear it. Found by reading the rules, not the tests.

A laboratory scientist pipetting a sample into a test tube. — Real-world context · Julia Koblitz / Unsplash

01 · Evidence

The result, with the gap left visible.

Why the stand-down gate must key on collection time: culture carries a pre-declaration sample past the declaration.

Sample #4021 — E. coli, Kauri Village supplyMonday 08:00 → Tuesday 06:00

filter: createdAt > declaredAt✓ counts as a post-incident clearThe import landed after the declaration, so the gate accepted it. The sample predates the contamination entirely.

filter: collectedAt > declaredAt✗ excluded — predates the incidentCollection time is the authoritative one. An unknown collection time is excluded fail-closed: unknown is never safe.

Why the stand-down gate must key on collection time: culture carries a pre-declaration sample past the declaration.