School Water Points Sized by Queue Physics: How Many Taps a School Needs So That Filling a Container Fits Inside a Twenty-Minute Break

SIMULATED, NOT MEASURED. A transient queueing model (analytic bound plus Monte Carlo simulation) sizes school water points so at least 95% of pupils seeking water finish filling within a 20-minute break. For 300 pupils, 0.5-litre containers and 6 L/min taps, 2 taps are required; a single tap serves only 66.5% of seekers within the break. Adding the second tap saves a simulated 511,670 pupil-minutes per school year. Failure cases: single-tap schools and mid-break flow collapse from a low-yield source, where storage volume becomes the binding constraint. No installation has been built; nothing is measured.