Water loss can be costly for utilities – the first step in reducing it is isolating the problem. The key to doing so is collecting and accessing quality field data.
Non-revenue water (NRW) or water loss can occur from pipes that are broken or leaking, poor meter monitoring, data errors, or even theft. Unbilled, authorized consumption such as water used by fire departments can be another source of NWR which is inevitable and usually unmetered but should still be tracked.
Though the percentage of lost water to overall water supplied can be fairly low (or sometimes very high – think: 40%!), reducing NRW can help utilities make tangible financial gains.
In this blog, you’ll read about:
How to reduce water loss
How to get the right data in order to analyze the problem and isolate the issue
How do you put together a plan to isolate the problem and fix it
Some visible losses can be unavoidable but we’re going to talk about leaks that go beyond the unavoidable, and impact undue operational costs.
Aside from revenue, in areas like California, there are water shortages so every last drop that can be accounted for is important to their overall supply. Understanding the data can go a long way – it can help you understand where you can recover water within your system that doesn’t cut into your resources. It can also be a pulse check that forces you to check your assets regularly, so you know what is going on within your system. Water loss management has a huge cost-benefit and utilities should be tracking usage whether they’re billing for it or not.
Rather than guessing where your water is going, you can chip away at what you know. Understanding what is happening above ground, for instance, may be a good place to start.
Even though your fire department’s water usage probably isn’t metered, you can ask for an estimate of how much water they’re using and keep a record of it. (They might have the answer!)
If there is a water main break, ask your crew how long they think it was running so you can estimate the water loss.
If you collect the data at least 3 times, you’ll get a better estimate moving forward.
Once you know the amount of water you’re losing in these areas, you’ll have a better idea through the process of elimination as to where the rest of it may be going so you can isolate the issue.
Let’s get you started
Do you have a list of all your known sources of non-revenue water? You can start by estimating the volume of water used by each source.
Confidently Estimated Municipal Use (CEMU)
Estimated million gallons per year
Fire protection & training
Hydrant / water main flushing / main construction
Bleeders / blow offs
Tank overflow & drainage
Sewer & stormwater system flushing
Source meter calibration adjustments
Major water main breaks (not leak detection)
Data points you want to be tracking to get your data in the right shape to understand water loss
1. Water Supplied Metered flow into distribution (treatment plants, well production, imports) Data archived per meter Inventory of key production instrumentation (no redundancies) Important to flag estimates or accuracy issues Note derivation of volume (totalizer, SCADA sampling, etc.) 2. Authorized Consumption Accounting of all authorized withdrawals from distribution Billed metered Unbilled metered Billed unmetered Unbilled unmetered 3. Infrastructure Data Up-to-date summaries of Total pipe mileage Total service connections (active and inactive) System-wide pressure information 4. Meter Accuracy Records of any customer meter accuracy test work Small meter bench tests Large meter bench tests Flow rates tested, volume tested, test results 5. Leak Repair Records Time of incident reported to agency Time of flow containment Flow rate upon inspection Type of infrastructure leaking (type, size, material) Type of failure