Question

explain why water comes out more slowly from an upstairs tap then from a similar tap downstairs

Answer 1

pressure of water increases relatively to its depth
that tap downstairs has more pressure of water so water comes quickly out in under one

Answer 2

The pressure of Water in the pipes is called the" head of pressure "and it is the difference in level between..the water surface height (above sea level )in the nearest reservoir to the height( above sea level )of your tap.This" head" will be higher for a downstairs..tap than an upstair tap and therefore the pressure and water flow rate of upstairs will be less than for downstairs..