Second water meter in a duplex

[Jeff S.]

Old Portland duplex with single water line. Have owned many years and always wanted to add a second line but the cost.

Would you EVER consider spending $17,800 to save $2493 per year in water cost?  We do know that water will keep going up. The payback is around 7 years.

Yes I know about submetering and all but trying to keep track of all that lots of work.

[Greg Scott]

If you are renting out one or both sides, you can bill back for water usage, even without a second meter.  If you don't want to split it by some formula, such as number of people, you could always charge a flat rate.  

If you did the either of the above, there doesn't seem to be much savings at all.  How do you get to $2,493?   You would probably have a much bigger benefit from low-flow water fixtures.