For example with proper water saving devices the amount of water used for toilet flushing alone could be reduced by 50%, or by about 16 m3/p/yr.
(the amount of water; used; for toilet flushing alone) (the amount of water used for toilet flushing alone; could be reduced; by 50%, or by about 16 m3/p/yr)
the amount of water the amount of water used for toilet flushing alone
used could be reduced
for toilet flushing alone
by 50%, or by about 16 m3/p/yr