Why does your washing machine cause hot water loss throughout the house even when washing with cold water all pipes are copper as soon as washing machine is finished hot water is restored?

Poor design of the piping system as you may have adequate pressure but not enough volume as the sizing of fixture units is predicated upon available pressure and amount of volume needed to prevent drastic pressure / volume drops (loss) Poor design of the piping system as you may have adequate pressure but not enough volume as the sizing of fixture units is predicated upon available pressure and amount of volume needed to prevent drastic pressure / volume drops (loss)