Mexico City, Mexico
#00215
Case study of
#00200 Subsidized household rainwater harvesting for water-poor neighborhoods
Implementer
SEDEMA (Mexico City environment ministry) with Isla Urbana and local installers
Timeline
Since Jan 1, 2019
Location
Description
The Cosecha de Lluvia program, run by SEDEMA (Mexico City's environment ministry), scaled the citizen-designed Isla Urbana kit (Tlaloque first-flush separator, cistern, and filters) with public subsidy: approximately 62,700 subsidized systems installed from 2019 to 2023 for roughly US$70M (~US$1,100 per system), targeted at water-poor southern and eastern boroughs where network supply is intermittent. Isla Urbana itself has installed about 45,000 systems, harvesting roughly 6.6bn litres per year. Systems supply about 5–8 months per year of non-potable and filtered use. The program survived the 2024 administration change.
Metrics
6Funding
Lessons learned
- A kit designed with and for informal housing (first-flush separator, right-sized cistern) is what made subsidy money effective at scale — generic hardware would not have fit rooftop configurations in these boroughs.
- Pairing city subsidy with NGO delivery (Isla Urbana) and trained local installers allowed scale-up from pilot to ~62,700 systems in four years.
- Targeting by water poverty (intermittent network supply in southern and eastern boroughs) concentrated benefits where tanker dependence was worst; 65% of direct beneficiaries were women.
- Program continuity across an administration change is a concrete prerequisite to plan for: build institutional and community buy-in before the electoral cycle ends.
Sources
1Documented Jul 24, 2026