How to bill for Well water and Oil heat for multi family?

[Davis Stoner]

So I just closed on my first investment property!

It has been a crazy experience so far and I'm sure it won't stop here.

-Luckily each unit has their own oil tank- What I was thinking about doing was filling it up before the tenants move in and then when they move out I use their security deposit to fill it back up for the next tenant. They are responsible for filling it up throughout their stay. I would have all of this in the lease. Does this sound like a good idea or does anyone have any other ways to go about this situation?

-My other "issue" is all 3 units share 1 well. I am trying to keep the water usage down because I am skeptical of the septic tanks. The town is switching to public water/sewage in a few years so I just have to make it till then. Does anyone have any recommendations for easy to use/install submeter companies? I would like to put the meter on 3/4 pex tubing if possible. 

Thank you and I appreciate any and all advice!