What Is RUBS Utility Billing? How to Split a Shared Utility Bill Between Tenants, With Worked Examples (2026)

The question usually arrives with a duplex or a small apartment building that has one water meter, or one gas meter, for everyone. The city bills the owner. The owner either folds the cost into rent and absorbs every increase, or passes it through to the tenants. Passing it through means deciding who owes what, and doing it the same way every month without an argument.

What Does RUBS Stand For?

RUBS stands for ratio utility billing system, sometimes called allocated billing or, in Minnesota's statute, apportionment. Each unit is assigned a ratio from facts about the unit (its size, how many people live there, sometimes bedrooms or bathrooms), and that ratio is applied to the building's bill. It is an estimate of use, not a measurement of it.

It is most common for water, sewer and trash, which are rarely metered per unit in older buildings, and sometimes for gas on a shared boiler. Electricity is almost always metered per unit already, and some states forbid splitting it by formula at all.

How RUBS Compares to the Other Options

Method	How it works	Best for	Drawback
Utilities included in rent	The owner pays the bill and prices it into rent.	Single rooms, furnished rentals, very small bills.	The owner carries every rate increase and there is no reason to conserve.
RUBS (allocation)	One bill split by a formula: equal, square footage, occupants, or a weighted mix.	Small multifamily buildings with a shared meter.	An estimate. Low users subsidize high users.
Submetering	A meter on each unit, read monthly; each unit pays for what it used.	Larger buildings, or a remodel where pipes are open anyway.	Installation cost, often thousands of dollars where plumbing is shared.
Separate utility accounts	Each unit has its own meter and its own account with the utility.	Any unit that can be separately metered.	Not possible without separate service lines.

How to Calculate RUBS, Step by Step

Every RUBS formula follows the same three steps.

1. Take the common-area share off the top. Landscaping irrigation, a shared laundry room, a pool, the owner's own unit or office, and vacant units all used water no tenant household used. Estimate it (a separate irrigation meter, a laundry machine count, or a fixed percentage you can justify) and subtract it. Texas requires this deduction for allocated water, and Minnesota forbids charging tenants for any of it.
2. Choose the factor and find each unit's ratio. Unit factor divided by the building total. A 1,000 square foot unit in a 3,000 square foot building has a ratio of one third.
3. Multiply the remaining bill by each ratio. The shares must add back up to the amount you allocated, to the cent.

Worked Example: One $600 Water Bill, Four Ways

A four-unit building gets a $600 water and sewer bill for the month. The owner estimates that landscaping and the shared laundry account for 10%, so $60 stays with the owner and $540 is allocated. The building totals 3,000 square feet and 8 residents.

Unit	Size / residents	Equal	By square footage	By occupants	50/50 hybrid
A	1,000 sq ft / 3	$135.00	$180.00	$202.50	$191.25
B	800 sq ft / 2	$135.00	$144.00	$135.00	$139.50
C	700 sq ft / 1	$135.00	$126.00	$67.50	$96.75
D	500 sq ft / 2	$135.00	$90.00	$135.00	$112.50
Total	3,000 sq ft / 8	$540.00	$540.00	$540.00	$540.00

Equal split. $540 ÷ 4 = $135 each. Simple, and only fair when the units are alike. Here the one-person studio pays the same as the family of three.

By square footage. Unit A has 1,000 of 3,000 square feet, a ratio of 33.3%, so $540 × 1,000 ÷ 3,000 = $180. This tracks heating and cooling well and water poorly: Unit D has two people in the smallest space and pays the least.

By occupants. Unit A has 3 of 8 residents, so $540 × 3 ÷ 8 = $202.50. This tracks water use most closely, because people use water, and it is the formula Minnesota requires for water and sewer. It also means updating the count whenever someone moves in or out.

50/50 hybrid. Half the bill by square footage, half by occupants: Unit A pays ($180 + $202.50) ÷ 2 = $191.25. It is a common choice because it softens both extremes. Weights other than 50/50 work the same way.

If Unit C sat empty for the month, its share would not move to the other three. The owner pays it. That is the rule in Minnesota and the practice that keeps the formula defensible everywhere else.

Which Formula Is Fairest?

• Water and sewer: occupants, or a hybrid weighted toward occupants. Usage follows people, not floor area.
• Gas for heat, or a shared boiler: square footage. Space is what gets heated. Minnesota requires square footage for gas.
• Trash: equal, or by occupants. A one-bedroom and a three-bedroom put out different amounts.
• Identical units: equal is fine, and it is the easiest to explain.

Whichever you choose, the formula matters less than consistency. Apply it the same way every month, round in a way that adds back to the bill, and show the tenant the arithmetic. Disputes rarely start over the method; they start when the number changes and nobody can see why.

Where RUBS Is Restricted or Banned

Most states have no statute on RUBS, so it is allowed when the lease discloses it. A handful set rules, and a few cities forbid it. These are the ones landlords most often run into:

• San Jose, California bans ratio utility billing (Municipal Code § 17.23.315).
• Minnesota (Stat. § 504B.216) forbids apportioning electricity, requires square footage for gas and occupants on the lease for water and sewer, bars charging for common areas, vacant units and amenities, caps the administrative fee at $8 per billing period and the late fee at $5 a month, lets tenants request the actual bills for the past two years, and requires a prescribed "Utility Bills" notice attached to leases signed or renewed since January 1, 2025.
• Texas requires owners who bill tenants for allocated water and sewer to register with the Public Utility Commission and use the allocation formulas in its rules (16 TAC § 24.281), which include a deduction for common-area use. Overcharges must be refunded.
• North Carolina bars allocating the cost of hot water by formula.
• Arizona, Colorado and Montgomery County, Maryland allow it, with consumer protections attached.
• Oregon does not let a landlord bill tenants more than the utility charged the landlord.

Source for the list beyond Minnesota and Texas: the National Consumer Law Center's introduction to ratio utility billing systems. Rules change and cities add their own, so check your state utility commission and local housing agency before you send the first bill.

What the Lease Should Say

A RUBS charge the lease never mentioned is a charge a tenant can refuse. Put these in the lease or a utility addendum the tenant signs:

• which utilities are allocated, and which are included in rent;
• the exact formula, including the factor, any weighting, and the common-area deduction;
• any administrative or billing-company fee, in dollars;
• when the utility bill is due and what happens if it is paid late;
• that the tenant can see the master bill on request.

For a move-in or move-out partway through a billing period, prorate the unit's share by days occupied, the same way you would prorate rent for a partial month. And when a tenant moves out owing utilities, unpaid charges the lease made them responsible for are usually a permitted deduction from the deposit, within the return deadline your state sets.

If You Are a Tenant on RUBS

Ask for three things: the formula, the master bill, and your unit's numbers. Then run the arithmetic yourself with the steps above. If the shares add up to more than the bill, if common areas or empty units were not deducted, or if the formula was never in your lease, raise it in writing. Utility charges also count toward what you can afford: when you compare a listing against the 3x rent rule, add the average RUBS charge to the rent first.

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This article is general information from IROIRO, LLC and not legal advice. Utility billing rules vary by state and city and change over time; confirm the current rule with your state utility commission or local housing agency, or speak with a landlord-tenant attorney or legal aid office in your area.

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