I was speaking to an investor today who has around 12 properties and he suggested it wouldn't be doable because the tenants wouldn't want to pay half of water and electricity usage and I would have to pay for it all. I don't see this being the case - as long as they agree to it when they sign the lease there shouldn't be an issue.
Exactly - the tenants will pay for whatever you put in the lease - that's what they agree to.
However, be careful - I'm not sure what the local tenancies legislation is for where you would buy, but in Adelaide you can only charge for water usage if you have separate meters.
I have two of these types of properties and I pay for all water, including usage. No big deal really - you can't charge a tenant for water usage in Sydney unless you have water-saving shower heads and such installed anyway. Usage is a small part of the overall cost of water anyway.
I've read somewhere that if the plumbing into the two dwellings is separated (unlikely for a house conversion - but might be possible with a bit of work), you can buy water meters that you insert after the main water meter to do your own calculations of usage - then you can bill the tenants based on that. I've never done this, so have no idea about cost or what is involved.
One of my properties already had separate electricity meters for upstairs vs downstairs when I bought it and I paid for the other property to separate electricity. Now electricity is 100% the tenant's responsibility - I never see the bills, they deal directly with the electricity company. Much easier that way.
I do have shared gas meters, so I pay the bill and then the tenants pay 60/40 (3 BR upstairs / 2 BR downstairs) of those costs.
Having by-laws is a good idea.
You don't need by-laws, this isn't a strata property - you just need to make sure it is documented who gets access to what so that there are no arguments.
I realise insurance may be slightly higher on a multi-dwelling. I'm assuming the insurer would want to inspect it so I'd probably want to have some sort of certification to prove it complies with the BCA.
I think you are over-thinking this somewhat. I don't think the insurer will want to inspect it, I've just swapped to a new insurer and neither the original or the new insurer was interested - my broker just inserted a description of the dwellings into the schedule so it is documented. Because my properties have always been set up this way, I can't compare insurance costs to what it would be were they not multi-dwelling.