Auditing Non-Revenue Water: Essential Tools For Large Campus & Municipal Water Loss Surveys

Auditing Non-Revenue Water: Essential Tools For Large Campus & Municipal Water Loss Surveys

If you manage water distribution, whether for a manufacturing complex, higher education, healthcare, or for one of the thousands of communities across the United States, one of your biggest line items, and headaches, is non-revenue water. 

What is Non-Revenue Water? 

Non-revenue water (NRW) refers to water that is lost within a distribution system. The American Water Works Association, or AWWA shifted terminology from “unaccounted-for water” to non-revenue water because water loss is always accounted for: the difference is whether the water was consumed for benefit, or lost to waste. 

So, NRW is water that did not flow to its intended beneficial location, where either its users could utilize it, or that a utility could realize profit from its transmission. 

“NRW is specifically defined to include the sum of specific types of water loss and any authorized, unbilled consumption that occurs within water distribution systems”

NRW is, at its core, a leak, usually an underground water or slab leak… And America has a lot of leaks. 

How Much Water Is Leaking from America’s Water Pipes? 

The U.S. EPA reports that about seven billion gallons of treated water are lost annually to water pipe leaks and two-three trillion gallons are lost overall to cracked or damaged water distribution systems; with nearly one trillion of that number lost to simple household plumbing leaks. 

Which means at least two trillion gallons of water – enough to fill up 3.28 million Olympic-sized swimming pools – is lost from underground pipes every year.

All that NRW is expensive, too. The American Society of Civil Engineers (ASCE) estimates over
$2 billion is lost to leaking pipes across the aging US plumbing and water treatment infrastructure system. When you think about the fact that on any given day, water could travel through ancient wooden pipes, ceramic, metal, and PVC as it flows, you begin to realize the monumental task facing water facility managers when it comes to finding what is lost.

Can You Actually Manage Non-Revenue Water? 

The question on every large facility and municipal water official’s mind is how to find and save NRW to turn it into revenue-producing water. With the staggering complexity of the underground water infrastructure made up of some 1.5 million miles of pipes throughout the nation – in various states of repair – managing water loss can feel like a lost cause. 

It does not have to be. 

The length of time it takes to track down and repair your various pipe defects is dependent on the scope of your infrastructure, but with the right equipment, training, and a long-term plan, it can be done. Your secret weapon in your pursuit of non-revenue water is an annual water loss survey.

Anatomy of a Water Loss Survey

Water loss surveys, also known as water audits, can provide you with an annual check-up of your water lines, so that you are not responding to sudden pressured drops reactively, but proactively planning maintenance and repairs to hopefully find and repair them before they happen. 

“If they call us, there’s a reason… they have high water bills, surfacing water, low pressure, or dirty water… They don’t know how to deal with it in house, so the answer is to find a professional who specializes in leak detection and subsurface infrastructure to come out and do a full system survey.” – Zander Seaman, GPRS Project Manager, Leak Detection

The truth is that most water infrastructure and facility managers only worry about water loss if there is an emergency like a sudden pressure drop, or if their fire protection system fails a flow test. By the time you know you’re losing water, you’ve likely inconvenienced your community, damaged underground or above ground infrastructure, and lost thousands of dollars in water. 

“When a water main breaks, or a leak is happening, it’s going to wash out a lot of surrounding fill material around it, which could potentially undermine high pressure gas mains, communications, or high voltage duct banks, which could eventually cause them to fail, collapse or break.” – Zander Seaman

To effectively plan and catch small defects before they become literal sinkholes, you can hire a professional leak detection company like GPRS, whose Project Managers are trained non-destructive acoustic leak detection specialists, to conduct a full water loss survey of your pipes. 

If there is a leak in a pressurized water line, GPRS Leak Detection Services can find it.
In most cases, pipe material, depth, and whether the pipes are under soil, slab, or asphalt make no difference. We can locate pressurized line leaks under slabs or asphalt, as well as underground, by employing a variety of technologies that allow to “hear” differences in pitch between a healthy line and a leaking one.

Workers conduct leak detection services on a construction site.
Acoustic leak detection is the first line of defense in a water audit.

Listening for Leaks: Acoustic Leak Detection

The first line of defense in a water audit is acoustic leak detection. Highly trained Project Managers have years of experience listening for leaks and can pinpoint the location of water loss with surprising accuracy. To do so, they deploy a specially calibrated microphone like the DXMic, noise canceling headphones, and sometimes an “elephant foot” insulated sound dampener to listen to the pipes. 

Illustrations of Leak Correlators

Confirming Leaks: Leak Correlators

Another tool in the Project Manager’s arsenal is a leak correlator. This device also utilizes sound waves to create a visible digital readout of the variance in sound to allow the Project Manager to confirm and pinpoint the precise location of the defect or break. It must be grounded on one end of the pipe being located, so is often grounded on a nearby hydrant so that it can conduct the current that “hears” the leak via the correlator’s algorithm. 

A SIM-certified Project Manager is an elite leak locator. They can locate the specific pipe that is leaking and zero in on the exact point of water loss, be it a crack, a leaking valve, or other defect. In most cases, they can assess a water system in a few hours and mark out each specific leak above ground so that crews can excavate only exactly where it’s needed to repair the leak. 

By repeating these steps throughout your facility or municipal water infrastructure, you can have a snapshot of any major pressurized system leaks. When you repeat this water audit annually, you can monitor any NRW progression and maintain a healthier system. 

Finding Problems Before They Cost You: Video Pipe Inspection

In addition to annual water loss surveys, large facilities, campuses, and communities can also request a NASSCO-certified video pipe inspection report, where GPRS VPI Project Managers provide actual eyes-on photo and video footage of every inch of traversable pipe via CCTV push and lateral launch cameras. These robotic cameras can be deployed into dry pipes, and can in some cases be floated into active pipes to capture every pipe defect on digital video. 

GPRS then provides a full interactive VPI report that includes photos, video, and a breakdown of each pipe defect, coded by severity so that you can plan and maintain your systems with confidence. 

When you consider the amount of NRW lost inside your system and the long-term damage pressurized water line leaks can cause to the rest of your infrastructure, building a line item into your annual budget for a water loss survey could save you tens of thousands of dollars annually. 

GPRS specializes in Intelligently Visualizing The Built World™, above and below ground, to save time, money, and even lives. 

What can we help you visualize? 

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