How much would the sea rise if we stopped storing water in our houses?

Assuming everyone was storing maybe a cubic metre of water, (although some people have very big swimming pools most people maybe only have a little tank of water in the loft between four or five people). So with ten billion people we'd have 10,000 billion litres of water stored. If you work out the area of the Earth it comes out at about 100,000 billion square metres so maybe sea level would rise by about a millimetre.The calculation is that every twenty thousand years or so enough water arrives from outer space to raise the level of the oceans about an inch. So, it's miniscule against that.