Currently, there's only one water meter for the entire duplex, and historically, I've been responsible for paying the water bills every month.

However, I believe it's time to transition to a system where the water bill is split between the two tenants. I'm seeking advice on the best way to implement this fairly and effectively.

Here are a few options I've considered:

1. Submetering: Installing individual water meters for each unit could be a solution, allowing each tenant to be billed based on their usage. However, this might involve significant upfront costs and logistical challenges. Has anyone successfully implemented submetering in a similar situation?
2. Equally Splitting the Bill: One straightforward approach could be to divide the total water bill evenly between the two units each month. While this might seem fair on the surface, it may not accurately reflect each tenant's actual water usage.
3. Usage-Based Billing: Implementing a system where tenants are billed based on their actual water consumption could be fairer. However, without individual meters, accurately measuring usage for each unit could be challenging. Are there any practical methods for implementing usage-based billing without submetering?
4. Including Water in Rent: Another option is to adjust the rent for each unit to include the cost of water. While this simplifies billing, it may not be the most transparent or equitable solution.

I'd greatly appreciate any insights, experiences, or alternative solutions that members of the community have to offer. How have you handled similar situations in your rental properties? What strategies have you found to be most effective in fairly splitting utility costs among tenants?

Thank you in advance for your help and guidance!