How to audit commercial utility bills: a repeatable process

A utility bill audit is not a one-time treasure hunt. Done well, it is a repeatable process you run every billing cycle so errors get caught in the month they happen, not years later. That matters because the errors are common: one widely cited figure puts the share of organizations overcharged on utilities at around 80 percent, and industry analyses estimate that 15 to 20 percent of commercial energy invoices contain inaccuracies.

This is the process, laid out so you can run it consistently across one building or five hundred.

Step 1: assemble the account picture

Before you check a single number, get the context. For each account, gather the current tariff or rate schedule, the rate class, meter details (including any multiplier), contracted demand, any tax-exemption status, and at least 12 months of bills. Most audit errors are only visible when you compare a bill against the rules that are supposed to govern it.

Step 2: verify the account setup

Setup errors are the most expensive because they repeat every month until someone notices.

• Rate class: is the account on the correct schedule for its size and use?
• Tariff version: is the current, approved rate actually being applied?
• Meter multiplier: does the constant on the bill match the meter?
• Tax and exemptions: are sales-tax exemptions applied where the entity qualifies?
• Riders and fees: do the riders on the bill belong to this rate class?

Step 3: reconcile the meter and usage

Now check that the usage is real and internally consistent. Confirm the read is actual, not estimated, and that the days in the billing period line up with the read dates. A run of estimated reads that never trues up is a classic source of drift. Compare usage against the account's own history and against weather to spot values that do not make sense.

Step 4: recompute the charges

This is the core of the audit: take the verified inputs and recompute the bill yourself, line by line, against the tariff.

1. Recompute energy charges: usage times the correct rate for each tier or time-of-use period.
2. Recompute demand charges against the tariff, and check any ratchet was applied correctly.
3. Check power factor or reactive charges against the tariff threshold.
4. Verify fixed charges, riders, and pass-through costs match the schedule.
5. Confirm taxes are calculated on the correct base and any exemption is honored.

Step 5: document and pursue recoveries

When you find an error, document it precisely: the account, the period, the tariff rule, and the dollar impact. Many utilities allow back-billing corrections within a defined window, often around 36 months, so time and precise evidence both matter. Utility auditors report finding at least some overcharge on the large majority of accounts they review, with independent reviews reporting errors on roughly 80 to 90 percent of the accounts audited, so a clean first pass is the exception, not the rule.

Step 6: make it repeatable

A once-a-year audit catches errors long after they started. The stronger model is to run the same checks on every bill, every cycle. That is only practical if the data is structured, because eyeballing hundreds of PDFs is exactly the work that does not scale and quietly gets skipped.

This is where MartinAI fits. It reads every field on every bill, then runs the same reconciliations an auditor performs by hand: recompute charges against the tariff, flag rate-class mismatches, estimated reads and duplicate lines, and surface anomalies against each account's own history. Your team spends its time only on the bills that genuinely look wrong, with the evidence already assembled. For a deeper look at where the money hides, see utility bill errors and overcharges.