The Pumped Gallon and the Billed Gallon Rarely Match: Read the Water Balance Before Blaming a Meter

Every water system keeps track of two totals that people tend to assume match. The first is how much water the system produces, measured at wells, intake pumps, or the outflow of a treatment plant. The second is how much water customers are billed for, measured by the meters on individual service connections. In a perfect system these would be equal. In practice they almost never are, and the gap between them is the starting point for a water balance.

A water balance is a simple accounting exercise. Start with the total water put into the system. Subtract the water that is authorized and billed. What remains is the portion that earned no revenue, and it includes several different things that need to be separated before anyone decides what to fix.

What Sits in the Gap

Some of the unbilled water is legitimate. Crews flush mains to clear sediment or dead ends. Fire departments draw from hydrants during training and during fires. Some towns run water through municipal buildings or parks without a customer meter. None of that is a failure, but a system that does not record these uses will treat them as losses.

Some of the gap is real loss. Leaks in mains and service lines lose water before it reaches a meter. Storage tanks can overflow. Unauthorized connections, less common in most small towns, also take water without a bill.

Some of the gap is measurement error. A customer meter that has aged may record less than actually passes through it, and a production meter that has drifted out of calibration may record more or less than the true pumped volume. Both sides of the balance carry their own uncertainty, which is why a single gap number tells you less than it appears to.

Why Meter Makers Are Part of the Story

Meter manufacturers and their suppliers sit close to this question because their products set the precision of both sides of the ledger. Badger Meter announced on Nov. 3 that it had acquired 37South, described in the announcement as a "utility technology and remote monitoring company" based in Melbourne, Australia. Water Finance and Management reported the deal (Water Finance and Management's report on Badger Meter's acquisition of 37South). The report does not describe what that technology does for any particular utility, so a town should not read it as a change to its own equipment. What it does show is that remote monitoring is an area where companies are combining capabilities, which is a reason for a town to ask its vendor what data its equipment collects, where that data is stored, and who can access it.

How to Build a Simple Balance

Pull twelve months of production totals from plant or well records, and billed consumption from the customer billing system. Ask the utility how it estimates unmetered uses such as flushing and fire use, and whether those estimates are written down. Ask when production meters were last calibrated and when customer meters were last tested or replaced. Then compare the unbilled share from one year to the next. A sudden jump points toward a leak, a meter problem, or a change in how flushing is recorded. A steady gap usually points toward a long-standing habit or a design feature of the system.

The American Water Works Association publishes a standard water audit method that many utilities use for this calculation. A town that asks for an audit in that format will get figures that can be compared with other systems, which makes the numbers easier to question and easier to explain at a public meeting.

What to Ask at Council

You do not need engineering training to read a water balance. You need the production totals, the billed totals, the list of unmetered uses, and the date of the last meter check. If the utility cannot produce those four items, the absence is itself information. A capital plan that targets leaks should start from a balance that shows where the water goes, not from a guess about where it might be lost.