Submetering vs RUBS: which fits a small apartment building?

What is the difference in plain terms?

Both tools answer one question: how do you charge each unit for a bill that arrives for the whole building? They answer it differently.

Neither one changes what the utility charges you. They only change how the cost travels to the tenants.

How different are the bills for the same building?

Take one four-unit building with one water and sewer bill. The split below is only to show the mechanics.

Example a made-up fourplex gets a $480 water and sewer bill. Units A, B, C and D have 1, 2, 2 and 3 occupants (8 in all). RUBS by occupants is $60 per person, so the shares are A $60, B $120, C $120 and D $180, which add to $480. The submeters read 2,000, 5,000, 3,000 and 6,000 gallons (16,000 in all) at a made-up $0.03 per gallon, so the shares are A $60, B $150, C $90 and D $180, which also add to $480. Unit B pays $30 more under the meters, and unit C pays $30 less.

Same total, different people paying. A tenant with two people who rarely run the tap will prefer a meter. A household that showers a lot will prefer the formula. That is why disclosure in the lease matters more than the method you pick.

Which states allow which?

The law decides, not preference. These are the five statutes opened for this guide. None of them is the whole law for its state, and your city or utility commission may add rules.

• Arizona: a landlord may charge separately through a submetering system or through a ratio utility billing system, if the lease discloses it (A.R.S. 33-1314.01).
• Virginia: submetering equipment, allocation equipment or a ratio utility billing system may be used if clearly stated in the lease (Va. Code 55.1-1212).
• Massachusetts: water charges for a dwelling unit come through submeters that meet stated conditions, including a licensed plumber and water conservation devices (G.L. c.186, section 22).
• North Carolina: water and sewer charges are generally based on the user's metered consumption, with narrow exceptions, and a ratio system is ruled out for the hot-water exception (N.C. Gen. Stat. 62-110(g)).
• Oregon: a landlord may charge what the provider billed for the unit or a common area if the written agreement says so, and must explain how the charge is allocated (ORS 90.315).

If your state is not on this list, read its statute or ask your utility commission or a local attorney before you pick. Which states restrict utility billing: five statutes compared walks through the differences side by side.

Which one suits a building with two to eight units?

A small building has a short list of realistic choices. In order of tenant fairness and effort:

1. Separate utility meters, so each tenant has an account with the utility. No allocation at all. Ask the utility what a split costs; it may need a plumber or electrician and may be impractical in an older building.
2. Submeters, where your state allows them. You bill actual use, and a tenant can see the readings.
3. RUBS, where your state allows it and the formula is simple enough to explain on one page.
4. All bills paid, with the utility cost built into rent. No billing, but no incentive to save.

A two-unit building often fits the last option or a simple per-person split. At six to eight units, the owner's monthly time on a spreadsheet starts to matter, which is the point where a meter or a billing partner earns its cost. Costs vary by building and by installer, so get quotes rather than rely on a rule of thumb.

One more consideration is conservation. The EPA notes that fixing easily corrected household leaks can save about 10 percent on water bills. A tenant on a meter feels that saving; a tenant on a flat formula does not. That is an argument for meters when the budget allows, not a rule.

Where DoorKeeping fits

DoorKeeping does not read meters, calculate a utility split or send utility bills to tenants. What it does is keep the paperwork around the choice: the AI reads each utility bill and codes it to the property's own books, the lease and the split worksheet sit in the unit's documents, and tenant payments land in your own bank, where the bank feed matches them by memo and exact amount. Anything involving money waits for your one-tap approval. This is general information, not legal advice. Statutes change, so read the current text and ask a local attorney before you bill a tenant.

Sources

1. A.R.S. 33-1314.01, Utility charges; submetering; ratio utility billing; allocation (Arizona Legislature), read Oct 31, 2026
2. Va. Code 55.1-1212, Energy submetering, sewer and water submetering equipment, and ratio utility billing systems (Virginia Law), read Oct 31, 2026
3. G.L. c.186, section 22, Definitions; submeter installation; testing; water use charges (Massachusetts Legislature), read Oct 31, 2026
4. N.C. Gen. Stat. 62-110(g) and (h), water, sewer and electric charges by lessors (North Carolina General Assembly), read Oct 31, 2026
5. ORS 90.315, Utility or service payments; additional charges (Oregon Legislature, Chapter 90), read Oct 31, 2026
6. Fix a Leak Week and checking for leaks (EPA WaterSense), read Oct 31, 2026

Questions

Is RUBS legal everywhere?

No. Arizona and Virginia allow it with lease disclosure, but Massachusetts describes charging by submeter and North Carolina generally ties charges to metered use. Read your state's statute before you start.

Is submetering always fairer than RUBS?

It is fairer to a low-use tenant because the bill follows use. It costs more to start and needs working meters, and some states attach conditions such as a licensed plumber.

Can I switch from RUBS to submeters later?

Usually yes, but a change during a lease may need the lease to allow it and notice first, as Arizona does with 90 days. Put the right to change methods in the lease at the start.