best way to split water meter for ADU / Duplex?

[Marcus Tam]

What is the best way / most cost effective way to split water bills between the mainhouse and the adu i am renting out? 

I called a few submetering companies but they only do commerical buildings. and with submeteres, i think someone has to physically be there to calculate the useage in the meters, divide the bill etc. that sounds like a lot of trouble, especially if i dont live on site.

any other solutions? 

[Charles Renn]

Hey @Marcus Tam, great question. A popular way to split the billing with installing any equipment is called RUBS, ratio utility billing system. If you google it, there are companies that can manage it for you or you can likely setup a system of your own depending on the work you want to put in.

Hope this helps!

[Jill F.]

check out FLOWS.com

I ordered flow meters  and wired remote readers and had my handy man install them on my duplexes. They are only a couple hundred bucks each and flows.com was VERY helpful allowing me to pick the proper products. This is only possible if you are certain that the plumbing supply lines for each unit are separate (you should be good if each unit has it's own main shut off).

[Dan Heuschele]

Fairest is submeter as @Jill F. suggested.  This is also least likely to get any complaints about the water charge.  Some people who use this method have a “fixed” rate that they charge monthly and only true up on occasion (example every 6 months).  When they true up, the fixed rate gets adjusted per the water historical use.  

CA allows equitable utilities split which basically means the Landlord  is not to charge more than the utilities.   We charge equitable by the unit size and not by occupancy due to the different time units turn over.   This is the easiest method but does get occasional complaints on the charge.  We typically only get one complaint.  We respond by pointing out if they were solo on the water bill, their bill would be much higher due to the various fixed costs being split.  We also state they agreed to the water bill split when they signed the lease and they are free to move out when the lease is up.  That pretty much guarantees we get no further complaint from the tenant as there is a housing shortage in our market and we provide quality housing at a very fair price for our good tenants (I.e. our existing good tenants all pay rent below market).  

Good luck