The practical planning path · lesson 5 of 7
5. Budget water between stops
Fresh supply and gray accumulation have different boundaries.
- 2 people × 10L = 20L/day
- 20L/day × 2 days = 40L
- Gray capture missing → unknown
Original worked-example diagram. Fresh demand and assumed usable capacity do not establish gray volume, available refill stops, tank fit or drinking-water safety.
Write occupants,days and activity use explicitly. Keep per-person use separate from whole-group equipment use. Nominal capacity does not establish usable capacity. Drinking use and captured gray water need separate assumptions; not all drawn water reaches the gray tank. Refill and emptying schedules can differ,and a planned stop may not be available. Distinguish US liquid and Imperial gallons before converting.
Worked example
Fictional inputs: two people use10L each per day,so fresh demand is20L/day. For two days between assumed full refills,40L is required. An assumed50L usable fresh tank leaves10L in this arithmetic. That margin says nothing about water safety or whether the refill stop exists. Gray volume still needs capture and starting-volume inputs.
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The gray side needs its own explicit inputs. Unknown capture is not zero and is not automatically100%.
Free next steps
Try the local water scenario · Keep contents mass separate
Continue: 6. Track mass and independent limitsSources and boundary
- Editorial worked arithmetic only; no reviewed tank/consumption or safety claim.
Original lesson reviewed2026-11-07. Examples are clearly identified above; no example input becomes a catalog fact. Learning checks do not award installation qualifications or certify competence. Lessons and continuation are free; no purchase,account or answer storage is required.