$172.62 per hectare per month ($2,071.44 / ha / yr) of total parcel area — not impervious area. Properties with a lot of green space pay the same base rate as fully-paved neighbours of the same size.

Lands over 0.4 hectares qualify for area-based charging and credit eligibility. Residential ≤ 0.4 ha pays a flat $20.74/mo and isn't credit-eligible.

Up to 50% reduction for industrial, commercial and institutional properties with a Professional Engineer storm drainage report demonstrating reduced runoff. Credit valid up to 5 years.

London bills by total area, so impervious is decorative here. The RGB-only classifier also misreads farmland — we've hidden the toggle until we have a deterministic source.

Darker border = SWM report on file — click for the structured analysis.