Do not carry tank overflow into later draw intervals.
Why can total inflow minus total outflow miss an empty-tank interval?
Use the matching calculator
Use this decision sequence
- Start with measured contained volume below the geometric capacity.
- Enter constant measured rates for each interval in chronological order.
- Record overflow when a positive interval reaches the capacity boundary.
- Record unmet net draw when a later interval exhausts the remaining contained volume.
Keep the quantities distinct
| Quantity or assumption | How to use it |
|---|---|
| Inflow total | Does not mean all inflow remains available. |
| Overflow | Leaves the tracked storage balance. |
| Unmet net draw | Shows volume absent when an interval tries to go below zero. |
Worked comparison
A 10 m³ tank starting at 5 m³ receives a net 4 m³ per hour for 2 hours. It ends full and records 3 m³ overflow. Drawing a net 4 m³ per hour for the next 3 hours empties it and records 2 m³ unmet draw. The earlier overflow cannot be reused in the second interval.
Check before using the estimate
This uses measured constant net rates within intervals. It does not select pumps, drainage capacity, water quality or an operating limit. The example values are illustrative arithmetic inputs. Replace them with your measured plan, selected product information and actual quote where relevant.
All dimensions, product properties, prices and specifications in this example are illustrative arithmetic inputs. Use the values from your measured plan, selected product data sheet and supplier quote. This guide does not choose construction specifications or certify safety.
Calculation and scope checked 2026-10-04. Methods and scope.