Billing every unit individually is slow but self-correcting, because you notice the odd one as you go. Billing the whole portfolio at once is far faster and has the opposite property: a single wrong rate or a stale meter reading goes out to two hundred people simultaneously, and you spend the next week answering for it.
The work is not in the sending. It is in the checking.
Get the inputs right before you start
Meter readings first, and dated. Every metered unit read within the same short window, with readings entered before anything is priced. A reading taken three weeks late puts consumption in the wrong month and creates a bill somebody can legitimately dispute.
Confirm move-ins and move-outs. A tenant who left on the 8th should not be billed a full month, and a unit occupied from the 20th should be pro-rated. This is the single most common correction and it is entirely preventable.
Check rate changes have been applied: new rent for units that were reviewed, new utility rates if a tariff moved. Once.
Then preview, and read it like a stranger
Before anything is sent, look at the run as a whole and ask four questions:
- Is anyone billed zero, or billed nothing at all? Usually a lease that never got activated.
- Is anyone billed twice? Usually a duplicate charge from a manual adjustment.
- Which bills moved most against last month? Sort by variance, not by unit number. The three biggest movers are where the errors are; the rest of the list is noise.
- Does any single bill look impossible? A water charge ten times the norm is a mis-keyed meter reading, not a leak, roughly nine times out of ten.
Five minutes on those four questions prevents most of the week that follows a bad run.
Send with the derivation attached
Every metered charge should carry its reading, its rate and its arithmetic on the bill itself. Not because it looks thorough, but because it converts "why is this so much?" from a phone call into a glance. See how to read a metered bill for what a tenant is actually trying to check.
When you get one wrong
You will, occasionally. Two rules:
Correct it as a new entry, not by editing the old one. A bill that silently changes after a tenant has seen it destroys more trust than the original error did. Issue a credit or an adjusting charge that references the original.
Tell everyone affected before they tell you. A message that says "we got the water rate wrong on this month's bills, here is the corrected figure, here is the credit" costs one message. Being found out costs the rest of the month.
Same date, every month
Predictability is worth as much as accuracy. Tenants who know bills arrive on the 1st and are due on the 5th behave differently from tenants who are surprised each month, and an arrears figure means something when the billing date is stable and nothing much when it isn't.