pressurised(p1).
pressurised(p2) <- on(t1) & pressurised(p1).
pressurised(hws) <- on(t4) & pressurised(p2).
pressurised(p3) <-  on(t1) & pressurised(p1).
pressurised(p4) <- pressurised(hws).
pressurised(p5) <- pressurised(hws).

flow(shower) <- on(t2) & pressurised(p2).
flow(shower) <- on(t5) & pressurised(p5).

wet(sink) <- on(t3) & pressurised(p3).
wet(sink) <- on(t6) & pressurised(p4).
flow(d3) <- wet(sink) & unplugged(sink).

wet(bath) <- flow(shower).
flow(d2) <- wet(bath) & unplugged(bath).
flow(d1) <- flow(d2).
flow(d1) <- flow(d3).

wet(floor) <- wet(sink) & plugged(sink).
wet(floor) <- wet(bath) & plugged(bath).

on(t1).
on(t2).
off(t3).
off(t4).
off(t5).
on(t6).
unplugged(bath).
plugged(sink).

