Your Water Meter Passed Its Test. Why Is Your Bill Still High?

A utility accuracy test checks the meter on a bench, at steady flow. Your building runs on sudden demand surges, and that’s when meters over-register. Both things can be true at the same time.

~1.5%

Typical test tolerance at normal flows (AWWA)

0

Demand surges in a standard bench test

Up to 30%

Typical water and sewer bill reduction with the FCD

Under 0.8 psi

Pressure loss across the FCD

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Direct answer: A meter "passes" when it reads within tolerance on a test bench at steady, controlled flow, but that test never recreates the demand surges in a working building. During those surges, water speeds up through the meter, pressure inside it drops, and gas and vapor form and are counted as water. So a meter can pass its test and still over-register every day in service. The Flow Conditioning Device (FCD) installs immediately after the meter and holds pressure up during those surges, with documented installations averaging a reduction of up to 30% in water and sewer costs.

Same Meter, Two Very Different Conditions

Infographic comparing a water meter on a test bench, with clean water at steady flow that passes within tolerance, with the same meter in a building, where sudden demand surges drop pressure inside the meter so gas and vapor form and are counted as water.

What a “Passing” Meter Actually Means

When a utility tests a meter, it runs a measured volume of clean water through it at steady, controlled flow rates, usually on a test bench, and compares what the meter recorded with what actually went through. If the difference falls within the allowed tolerance, the meter passes. Under standards from the American Water Works Association (AWWA), that’s typically within about 1.5% at normal flows, with a wider allowance at the lowest flows.

A passing result is useful. It tells you the meter isn’t worn out, damaged, or broken. What it doesn’t tell you is how the meter behaves in your building.

Why a Meter Can Pass and Still Read High

Valves open suddenly, booster pumps kick on, wash-down systems start, and dozens of fixtures run at once. During those demand surges, water speeds up through the meter and pressure inside it drops. Dissolved gas comes out of solution and vapor forms, and the meter counts that volume as water. None of that happens on the test bench, so the test can’t see it.

The meter isn’t broken. The conditions it’s measuring in are the problem. It’s not your meter. It’s your pipes.

Table showing what a standard meter accuracy test checks, such as accuracy at steady flow and mechanical wear, and what it misses, including demand surges, pressure drops inside the meter, gas and vapor counted as water, and the building's real 24-hour demand pattern.

Where the Extra Gallons Come From

Over-registration doesn’t happen all day. Overnight and during quiet periods, flow is steady and the meter reads accurately. The over-count builds up during the busiest hours, when surges are frequent and sharp. That’s why a building with a “passing” meter can still see a bill that climbs faster than its activity, especially during peak months or shifts.

Illustrative bar chart of water use over a typical day, showing the meter reading accurately during quiet hours and extra counted volume building up during the morning and afternoon demand surges that a bench test never sees.

If Your Meter Passed, Look for These Signs Instead

Your bill climbs faster than your activity

Water use on the bill rises faster than occupancy, production, or operating hours, especially during peak periods.

Usage doesn’t match your own records

Your submeters, production records, or occupancy data account for less water than the utility meter reports.

A clean leak check, but the bill stays high

Nothing is leaking, yet the bill doesn’t come down. The extra volume is being counted inside the meter, not lost in your pipes.

Sewer charges rise in step with water

Most sewer bills are calculated from the same metered intake, so an over-read inflates both charges at once.

Correcting the Reading, Not the Meter

Because the meter itself is fine, replacing it rarely helps. A new meter in the same conditions behaves the same way. The Flow Conditioning Device (FCD) works on the conditions instead. It installs immediately after the meter and creates a small, controlled back-pressure that extends back through the meter, holding pressure up during demand surges so far less gas and vapor form and are counted. Your building uses water exactly as before, and pressure loss across the FCD is under 0.8 psi across all flow conditions.

Documented installations show up to a 30% reduction in water and sewer costs, with the highest
documented result at 46%. Savings start on the next full billing cycle.

How each part of your service line affects the meter

How the FCD works

Passing Meter Tests: Common Questions

What does it mean when a water meter "passes" its test?

It means the meter read within the allowed tolerance when the utility ran a measured amount of water through it at steady, controlled flow rates. Under AWWA standards, that’s typically within about 1.5% at normal flows, with a wider allowance at the lowest flows. A passing result tells you the meter is mechanically sound.

If my meter passed, can it still over-register?

Yes. A bench test uses clean water at steady flow, so it never recreates the sudden demand surges in a working building. During those surges, water speeds up through the meter, pressure inside it drops, and gas and vapor form and are counted as water. The meter can pass its test and still over-register every day in service.

Should I ask the utility to test my meter again?

A retest can confirm the meter isn’t damaged or worn, which is worth knowing. But it won’t show surge-driven over-registration, because the test conditions don’t include surges. If the meter passes and your bill still doesn’t track with your activity, look at when your building uses water, not just how much.

How can I tell if surges are inflating my bill?

Look for water use on the bill that climbs faster than your occupancy, production, or operating hours, especially during peak periods; usage that doesn’t match your submeters or records; and bills that stay high after a clean leak check. Our free savings calculator models your building’s 24-hour flow pattern to estimate how much over-registration may be costing you.

How does the Flow Conditioning Device (FCD) help?

The FCD installs immediately after the meter and creates a small, controlled back-pressure that extends back through the meter, holding pressure up during demand surges so far less gas and vapor form and are counted. It doesn’t change your water use or the meter itself. Pressure loss is under 0.8 psi across all flow conditions, and documented installations show up to a 30% reduction in water and sewer costs.

Find Out What Your “Passing” Meter Is Really Costing You

Model your building’s 24-hour flow pattern in the free calculator, or send us your bills for a free savings analysis before you commit to anything.

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