Ratio Utility Billing System (RUBS): How It Works and How to Book It

A ratio utility billing system, or RUBS, splits a building’s utility bill among its units using a ratio. The ratio might be square footage, number of occupants, or bedroom count. Each unit pays its share. In the books, the bill is an expense. Income comes from the share you bill back. The owner pays the rest.

To “book” a recovery means to record it in the accounts. Get the entries right, and the owner statement makes sense. Wrong entries move NOI for no real reason. This guide covers the bookkeeping only. It shows the math, the entries, and what RUBS does to NOI and the owner statement.

Key Takeaways

• RUBS splits one utility bill across units using a ratio.
• Book the bill as an expense and the billed-back share as recovery income.
• The unbilled share, such as a vacant unit’s part, stays with the owner.
• Use the same basis every month, and keep records that back it up.
• Recoveries lift NOI, and the owner statement should show both lines.

How a Ratio Utility Billing System Works

1. 
   The formula is short. A unit’s charge equals its ratio, divided by the building’s total ratio, times the bill.

Here is an example with made-up figures. Picture a building with 20 units and 18,000 square feet. We use square footage as the basis.

Item	Amount
Monthly water and sewer bill	$5,400
Rate per square foot ($5,400 ÷ 18,000)	$0.30
One 900 square foot unit	$270
Occupied units (16,200 sq ft)	$4,860
Vacant units (1,800 sq ft)	$540

Add the last two rows, and you get the $5,400 bill. The numbers tie out. That is the test of a good calculation. If the parts do not add up to the bill, something is off.

Some programs take a common-area share off the bill first, for things like the pool, the laundry room or the landscaping, and split only what’s left. Book that carve-out the same way as the vacant share. It’s part of the owner’s net cost, so track it as its own number.

Choose a Basis and Write It Down

The basis is the ratio you split the bill by. Four are common.

• Square footage. It is easy to prove, since unit size seldom changes.
• Occupant count. It tracks real use, but the count changes and needs updates.
• Bedroom count. It is simple, but it is a rough guide to use.
• A mix. Some owners blend two, such as half by square feet and half by occupants.

From a bookkeeping view, the best basis is the one you can rebuild every month from records on file. Pick one. Write it down. Use it the same way each time. A basis that changes without notice makes every report harder to trust.

What the Basis Has to Survive: The Records You Need

Someone will ask how you got a number. It might be the owner, an auditor, or the next bookkeeper. Can you rebuild it?

Keep five records for that day:

• A written basis. One page that states the ratio and how you apply it.
• Unit data that ties to the rent roll. Square feet, occupants, or bedrooms for every unit.
• The utility bill and its service dates. Together they prove the total and the period.
• The calculation. It shows the rate, the rounding rule, and how you treat vacant units.
• A change log. When the basis changes, note the date and the reason.

Here is a simple test. If any stranger can reconstruct any unit’s charge from those files in ten minutes, the basis stands.

Set Up the Accounts First

Good entries need good accounts. Set these up before the first bill:

• A utility expense account for each utility. Keep water, sewer, gas, and trash apart.
• A recovery income account for each utility. It keeps the billed-back share visible.
• Tenant receivables. Billed amounts sit here until tenants pay.
• A memo line for the vacant share. It tracks what the owner absorbs.

Separate accounts let you check each utility on its own. They also make the owner statement easier to read.

How to Book a RUBS Recovery

You make three entries each month for each utility. We use the same figures as above.

Step	Debit	Credit	Amount
The utility bill arrives	Water and sewer expense	Accounts payable	$5,400
You bill the units their share	Tenant receivables	Utility recovery income	$4,860
Tenants pay	Cash	Tenant receivables	$4,860

The owner’s net cost is $540. That is the vacant share.

Now a choice. Some owners book the recovery as income. Others book it as a cut to the utility expense. Both give the same NOI. They change how the statement looks.

Method	Utility expense	Recovery income	Lift to NOI
Separate income line	$5,400	$4,860	$4,860
Offset against expense	$540	$0	$4,860

Pick one method and use it every month. A separate income line is easier to read, because you can see the recovery on its own. If the property’s financial statements are audited, agree the method with the auditor first: under GAAP, gross versus net presentation isn’t a free choice.

What RUBS Does to NOI

NOI is income minus operating expenses. Our guide to net operating income walks through each item.

A recovery adds income, so NOI rises by the amount you recover. In the example, that is $4,860 a month, or $58,320 a year. The $540 vacant share still lowers NOI. A vacant unit costs the owner its utilities.

Timing matters too. A late bill or a late recovery makes NOI swing from month to month. The swing looks like a change in the property. In truth, it is a change in the posting.

What RUBS Does to the Owner Statement

The owner sees your entries on the statement. Make them easy to read.

Line	Amount
Water and sewer expense	($5,400)
Utility recovery income	$4,860
Net utility cost to owner	($540)

Owners ask, “Why did utilities cost me $540?” The statement should answer. The gap is the vacant share.

Watch the timing. A bill covers last month’s use. You bill units this month. The statement can show the expense in one month and the recovery in the next. Match both to the service period, or add a short note.

Five Booking Mistakes That Skew the Books

Each one looks small. Together they hide what RUBS does to the numbers. Most come from habit, not from bad math. A short fix for each keeps the owner statement clean.

Booking the Recovery in the Wrong Account

What it does. Recovery income lands in rent income. It happens when the tenant ledger sends every charge to one account. Another cause is a wish for a single clean deposit line. In our example, $4,860 of recovery joins the rent total. Rent looks $4,860 higher than it is, and utilities look like a $5,400 cost with nothing recovered against them, when the owner’s real cost is $540. Nobody can see what RUBS brings in, and nobody can tell if it is worth the effort.

The fix. Give recoveries their own income account for each utility. Map the tenant charge code to that account so each bill goes to the right place. Review mapping quarterly and after any software change.

Changing the Basis Without a Log

What it does. The ratio varies from month to month, and no one comments on it. Someone might trade square footage for occupant count to fix one funky bill. Or the data for a unit may be altered without any file. Either way, you can’t rebuild the charges later. Say the 900-square-foot unit paid $270 in March and $310 in April. Nobody can say if it’s the bill, the basis or a slip. Trends are not meaningful and the owner loses confidence in the report.

The fix. Keep the one-page basis and the change log. Note the date and the reason for every change. Record who approved it, too. When the basis changes, run the old and new numbers side by side for one month. That shows the owner what moved.

Booking the Expense and the Recovery in Different Periods

What it does. You post the bill in one month and the recovery in another. Utility bills arrive after the month ends. You bill the units the next month, and tenants pay a month after that. If the expense and the recovery fall in different months, the statement misleads. One month shows a $5,400 expense with no recovery. The next shows $4,860 of recovery with no expense. NOI swings, though nothing changed at the property. The owner calls to ask what went wrong.

The fix. Match both to the service period. If the bill hasn’t arrived by close, accrue it from the last bill or the meter reads, accrue the matching recovery, and true both up when the actual bill lands. If the owner statement is on a cash basis, the two will land in different months whatever you do, so add a short note that says which months each line covers. Use one rule for every utility, and keep to it.

Losing the Vacant Share

What it does. Nothing shows the unbilled part, because it blends into the expense line. In our example, the owner pays $540 for the vacant units. The statement only shows $5,400 going out and $4,860 coming in. Finding the gap means subtracting, and most owners never do. That keeps the cost of an empty unit hidden. It also stops the owner from weighing it against a rent concession or a faster turn.

The fix. Track the vacant share as its own number. Show it on the statement or in a memo line. A simple net line, such as “Net utility cost to owner,” does the job. Update it every month so the owner can watch the figure fall as units fill.

Using Stale Unit Data

What it does. The unit file drifts away from the rent roll. A unit is reconfigured, a tenant moves out, or a new occupant moves in, and nobody updates the file. Say the file totals 17,400 square feet when the building is 18,000. The rate becomes $0.31 a square foot instead of $0.30, so every unit in the file pays a little too much to cover the 600 square feet the file has lost. The charges still add up to the bill, so the tie-out passes, and that is why this mistake survives month-end.

The fix. Tie unit data to the rent roll each month. Update it when a unit changes. Add one line to the month-end routine: total square feet in the file must equal the building total.

A Month-End Check for RUBS

Run this check after the books close.

1. Match the bill to the service dates. Confirm you booked the right period.
2. Check the unit data. Compare it with the rent roll.
3. Rebuild two charges by hand. Use the written basis. Do the numbers match?
4. Check the total. Billed amounts, plus the vacant share and any common-area carve-out, should equal the bill.
5. Review the statement. Look at the expense, the recovery, and the net line.

Then note anything unusual for the owner. The check takes minutes when the records are in order. It takes hours when they are not, so keep the files tidy.

Frequently Asked Questions

What is a ratio utility billing system?

It splits a building’s utility bill among units using a ratio, such as square footage or occupants. Each unit pays its share. The owner pays the unbilled part.

How do you calculate a RUBS charge?

Divide the unit’s ratio by the building’s total ratio. Multiply the result by the utility bill. Take a 900 square foot unit in an 18,000 square foot building. It owes 5 percent of a $5,400 bill, which is $270.

How do you record RUBS income in the books?

Record the utility bill as an expense. Put the billed-back share in its own recovery income account. Some owners offset the expense instead. Pick one method and use it every month.

Does RUBS change NOI?

Yes. A recovery adds income, so NOI rises by the amount you recover. The share you do not bill still lowers NOI.

What happens to a vacant unit’s share?

It stays with the owner. Track it as its own number so the owner can see the cost. In our example, it is $540 a month.

The Bottom Line

A ratio utility billing system is simple math with strict record keeping. Choose a basis. Write it down. Book the bill and the recovery in the right accounts, and match them to the same period. Then the NOI and the owner statement tell the truth.

If you want help with the books behind it, Outsourced Bookkeeping has 20+ years in business (est. 2004) and 75+ accountants on staff. Our property management accounting services cover monthly bookkeeping, reconciliations, and reporting for property owners and managers. Book a conversation and we will look at your books with you.