The Water Services Corporation is in the process of interconnecting its 24 reservoirs, allowing it to transfer water from one zone to another.
It said in a statement that this was being done to minimise the effects of maintenance works on consumers, allowing affected areas to be fed by more than a single source.
The improvement would also narrow the differences in water quality between regions.
All tap water, it pointed out, was still delivered according to the usual stringent quality procedures.