Free-standing rainwater catchment

Passive

Catches rain on its own surface rather than off a roof: a tarpaulin slung on a frame of poles, funnelling to a container. It is the option when there is no roof to use, or none worth drinking from, and it can be put up on ground the house does not occupy. Because the sheet is clean between showers in a way a roof is not, the first-flush problem is much smaller here, though what the sheet is made of then matters more.

One of 9 ways to meet Sourcing / extraction. Build 1/9, Upkeep 3/9, Efficiency not rated. Cost, carbon and footprint below are rated against those 9, not in absolute terms.

Cost: Low
Upkeep: Seasonal
Skill to build: Basic
Lifespan: Set by the sheet, which is the part that goes first: sun and wind degrade a tarpaulin long before the frame or the lashings give out
Embodied carbon: Low
Space / material use: Medium
Output timing: Weather/time-dependent
Skill to repair: Basic

What your site needs

Open ground clear of overhanging trees, and somewhere to anchor against wind: a sheet on a frame is a sail before it is a catchment

Inputs

Rainwater

Outputs

Unheated Water

Ranking in its sub-function out of 9 alternatives

Every option in this sub-function, with the value on each axis and a note on what drives it (this solution highlighted):

Solution	Build skill	Upkeep burden	Efficiency
Drilled well	Intermediate	5	N/A
Rainwater harvesting and storage	Basic	3	N/A
Spring capture	Basic	2	N/A
Manual/hand-operated well pump	Basic	2	N/A
Rope pump (manual, low-cost well pump)	Basic	2	N/A
Hydraulic ram pump (belier hydraulique)	Basic	2	N/A
Fog collector (cloud net)	Basic	2	N/A
Mains water connection	Specialist	3	N/A
Free-standing rainwater catchment	Basic	4	N/A

Build skill and upkeep burden are proxies (lower burden = simpler to maintain); the efficiency column is this sub-function’s ranking, 1 = best. “N/A” where an axis isn’t rated here.

Sources

Low-tech Lab wiki, self-supporting rainwater catchment tutorial (tarpaulin and poles)

Tutorials

https://wiki.lowtechlab.org/wiki/R%C3%A9cup%C3%A9rateur_d%27eau_de_pluie

What this page does not tell you

No sizing or quantities: how much a technique yields, and how much a household needs, both depend on the build and the people, so the catalogue compares options rather than dimensioning them. It carries no bill of materials and no build sequence, and it is written for an oceanic, clay-soil climate (Normandy, France). Regulatory notes are indicative and need confirming locally.