Whether or not a condominium association can change the water and sewer billing process from a metered usage a to a flat rate for all property owners depends upon what the recorded covenants, conditions & retsrictions state as well as all later approved amendments to such.If there is no mention of a flat rate, then most likely it cannot be assessed as a flat rate but must be metered. Sentiment is that metered rate is always the best and fairest way to assess a fee.Good question.