The main barrier to splitting the costs is that strata law is absolutely rigid on the principle that charges to owners should be levied on the basis of unit entitlements. The trade-off is that those who pay most get more votes.
You could possibly (and I’m not sure about this) separate the water bills so that only high-rise owners pay for high-rise water. You’d do this by asking the Tribunal for orders under section 87 of the Act (below) to allow for payment in a different manner.
This would not fix the problem of additional wear and tear in the high-rise section of the scheme but then it would shift the voting balance either.
Otherwise, I would be seriously tempted to calculate the inequity in costs versus payments and then seek adjustment of the unit entitlements on that basis. The fact that townhouse owners are more active and united in their views may offset the shift in power balance towards the tower owners.
A cleaner break would be to apply to the Supreme Court to establish two strata schemes, plus a community scheme for shared resources, but that could be so expensive that you’d soon swallow up any financial benefits.
Either way, you need a reliable strata lawyer and I wholeheartedly recommend our sponsors Sachs Gerace.
87 Orders varying contributions or payment methods
(1) The Tribunal may, on application, make either or both of the following orders if the Tribunal considers that any amount levied or proposed to be levied by way of contributions is inadequate or excessive or that the manner of payment of contributions is unreasonable.
(a) an order for payment of contributions of a different amount,
(b) an order for payment of contributions in a different manner.
(2) An application for an order may be made by the lessor of a leasehold strata scheme, an owners corporation, an owner or a mortgagee in possession.