Would it be worth to sub-meter water  in a duplex in Philadelphia Pa with an avg monthly bill of $80

Is the water for both $80/month?

If it helps, I installed them on a 20 unit.  You put the flowmeter in line with the HW heater feed.  Idea being if A uses 2x the HW of B, A is using 2X much and you can do a pro-rate.  The meters were about $175 each and you need to add install charge.  They're WiFi now, so it's simpler (if you have Internet access for the box that gets the readings.)

I'd do it since in PDX water/sewer is close to $100/unit/mon for 2 beds.  If you give them a flat rate, that's $50 (if that's the number) if you run the water 24/7 or if you don't use a drop.

The idea is to use less water since its a profit center for govt.

@Stephen A Jacquindo I personally don’t think it’s worthwhile. The hassle of either metering and billing monthly yourself isn’t worthwhile. And getting the tenant to change over their water bill in Phila, you might as well ask them to find the holy grail first.

I would suggest writing your lease to add an extra $30-$35/mo to the rent for water/sewer. Makes it easier to collect, no billing. I make it a bit less than the actual cost so if there's any question about being overcharged, I can easily say that they aren't. Sure, it's $10/mo out of my pocket, but the ease for both me and the tenant is well worthwhile.

I have inquired about getting sub metering in a duplex and triplex and the companies wouldn't do it. They had a minimum of 20 or 24 units for the cost of their services to be worth it.

This was in Evansville, Indiana so it couldn't hurt to contact a companies that service Philadelphia if you are interested in the future for large enough properties.

I have inquired about getting sub metering in a duplex and triplex and the companies wouldn't do it. They had a minimum of 20 or 24 units for the cost of their services to be worth it.

If you're talking about 3rd party billing?  Probably not.

I've got a 20-unit and it is not that hard to do pro-rates (assuming you know WORD and EXCEL) once you get the meters in.