I would double check the info you obtained from the water board, they may have misunderstood your situation.
It would certainly be a requirement for vilas and townhouses as these are essentially independent residence's but highrise units are slightly different and most don't have the opportunity to have separate meters.
In fact, a lot of new units have common hot water where the hot water is metered for the charging of gas usage but the water used for both hot and cold is still shared.
Possibly JoanneK who has just completed a large highrise could expand on how the utilities were dealt with in her building.
In our case we have both strata blocks and blocks of flats that don't have (or didn't have) meters. We have been progressively installing meters to be used by the RE for recharging of water use, but we still receive only the one water usage bill from the water board. We now have a situation that for some units we can't install meters as there simply is no place to install them. We tried with these units to install the meter inside the unit but it becomes problematic getting reading in a timely fashion so this idea has been abandoned.
Hard to comment on cost as we have done/are doing them progressively but the cost per meter (from plumbing supplies) is about $150 and then there is still the install cost on top.
Cheers