Splitting Water meter while currently having tenants dilema

[Ryan Cash]

I just bought a duplex.  one side is vacant and we are ready to advertise and get tenants in.  The other side will be vacant Oct 1 and we hope to have tenants in by November 1.  The property is currently on one meter and the average water costs have been $250-$400/mo from what the city told me.  That is a ridiculous waste of water!  The cost to install a separate meter is about $3400 with another $3-$400 for my plumber friend to do his work.  My question is if I am going to split the meter but I get tenants in before I do it, how would I structure my lease to say that landlord pays water until it is split and then tenants become responsible?  Or would it be best to suck it up for another month without a tenant, get the water split and start fresh with new tenants paying water from the beginning?  Thanks in advance.