Locking Down the Leaks
Drip, drip, drip.
The sound of a leak can be torture, especially for water system workers – mainly because it’s the sound of revenue going down the drain.
Leaks can cause losses of hundreds of dollars a year for customers and thousands of dollars a year for water systems. Massive leaks and pipe breaks are easy to spot and usually can be repaired quickly. It’s the small, hard-to-detect leaks that can cause major damage over time by destabilizing the ground and deteriorating pipes and structures around them.
This issue of the newsletter takes a look at leaks, how to find them and how best to prevent them.
Multibillion-Dollar Repair
Let’s start with a worst-case leak scenario. To do that, we’ll have to jaunt across the pond to Jolly Ol’ England, whose capital-city water customers aren’t so jolly lately. Come to think of it, London’s largest water system probably isn’t all that jolly either.
Thames (pronounced “tems”) Water announced at the end of June that it would spend about 1 billion pounds over the next year to fix leaks in the Victorian-era water system throughout London. In other words, those 100-150-year-old pipes are getting a facelift that in U.S. dollars equals about $2.02 billion. Yeah, billion with a “B.”
Why spend so much? Mainly because of the system’s leakage rate. Granted it’s dropped in the past year, but that’s hollow consolation when you hear the rate has dropped from a staggering 894 million litres a day, or 236,169,815 gallons a day, to ONLY 810 million litres a day, or 213,979,362 gallons a day.
Ouch.
The problem lies in old cast-iron pipes that have rusted in the acidic clay soil that blankets most of London. As a result, the pipes being replaced come out of the ground looking “like a colander,” said one water official.
So the company will spend the next year replacing 540 kilometres (about 336 miles) of pipes throughout the city.
Yes, the London case is an extreme case, but it brings up some good ideas to heed. Don’t just let leaks go – make the repairs as soon as possible. Check aging pipes for leaks regularly and replace them if needed. Make sure the pipes you use as replacements can withstand the soil around them for many years, whether it’s overly dry, usually wet or extremely acidic. The wrong material could mean costly repairs in the not-so-distant future.
Do I or Don’t I?
So how do you know if you have a leak? The easiest way to tell is to check the unaccounted-for-water ratio. A loss of 10-20 percent is about standard. Anything over 20 percent, and you have a leak or leaks somewhere that can cost you some serious revenue down the line.
The water loss percentage can be found by subtracting the metered water from the amount produced, multiplying that by 100 and dividing it by the water produced.
Unaccounted for water (percentage) = (Water produced-metered use) x 100
Water produced
This should give you a general idea of how much water your system is losing in a specific time period, be it a day, week, month or year. There are plenty of other resources and calculators out there for leaks from groups like the American Water Works Association and the U.S. Geological Survey. The National Wildlife Federation even provides a calculator to determine how much water a person uses each day.
Another tell-tale sign is water pressure. If water pressure is dropping in certain areas without new taps being added, it could be caused by a leak. Trying to increase the pressure can make things worse, because the added pressure could expand the leak or completely break the pipe at that weak point. If water pressure has dropped without new taps being added, it may be time to pull out the leak detection equipment.
Complaints of abnormally dirty or smelly water are another sign of a possible leak in the system, as well as an unusual jump in water use. Wet spots, sinkholes and other ground disturbances are the most obvious signs to look for, but they often mean the leak is large or has gone unchecked for quite a while.
We at the Safe Drinking Water Trust and eBulletin have created a flier for water customers to help them determine whether they have a leak and whether that leak is on their property – and theirs to fix – or on municipal property. Feel free to print and distribute the flier to customers. You can download it using the link below, or visit the Tips, Tools & Guides section of our Web site.
Additional Resources
American Water Works Association Water Wiser Drip Calculator
http://www.awwa.org/advocacy/learn/conserve/dripcalc.cfm [1]
U.S.G.S Drip Accumulator Calculator
http://ga.water.usgs.gov/edu/sc4.html [2]
National Wildlife Federation Water Calculator
http://www.nwf.org/water/watercalculator.cfm [3]
The Right Tools for the Job
The biggest problem with leaks is trying to find them. Customers have relatively simple methods available to them to help them find leaks. Water systems, on the other hand, have to rely on detailed maps, technology and a bit of good luck to pinpoint leaks.
One way to help narrow down possible leaks is to know your potential trouble spots. Make sure maps of the pipe system not only show where the pipes are, but also how old they are, what material they’re made from and whether problems have been reported in those pipes in the past. The maps provide a good starting point when looking for possible leaks, besides letting you know exactly where to dig once leaks are found.
One of the best tools for detecting leaks is a geophone. This device is made to measure ground motion, but it can be used to detect the sound of leaks as well.
A geophone looks a bit like a long stethoscope with two cups or cylinders on the end to listen to the ground. Geophones can range from a few dollars up to about $1,000, depending on the level of technology they include. Several companies make or lease such devices. Other devices include ultrasonic detectors, radar equipment and sensors that measure water levels in substances such as soil.
Any of these tools can help find leaks, but it may take more than one tool to do the job, especially with larger leaks. Small leaks spewing quickly from a pipe make more noise than water moving slower through a large breach in a pipe. Geophones may not pick up on the larger leak, but radar equipment may detect the increased water. In the end, keen observation of telltale signs, such as saturated or destabilized ground, may best help detect leaks.
Additional Resources
Geophones FAQ (Frequently Asked Questions)
http://www.tenrats.org/geo.shtml [4]
Due Diligence
The best way to deal with leaks is to prevent them. That’s not an easy thing to do, especially with communities growing rapidly and infrastructures aging so quickly. But there are a few steps that can help prevent leaks.
First, make sure close, thorough inspections are done on new pipes and water system expansions. One of the major causes of leaks is poor construction, from cracked pipes to seals and junctures that don’t fit quite right.
Second, keep accurate records and maps of the water system. Know where the aging or troublesome pipes are, so extra inspections can take place in those areas to catch leaks early.
Third, walk the system regularly looking for signs of possible leaks – wet spots, “ultragreen” vegetation, sinkholes, unstable ground and rapidly appearing cracks in pavement and structural foundations.
Finally, keep a close eye on your numbers. Watch for spikes in electrical usage or water usage or abnormal drops in water pressure or reservoir levels.
It wouldn’t hurt to let your customers know about these methods, so they can keep an eye out as well. Their familiarity with an area may help them spot abnormalities such as wet or ultragreen spots faster and easier. Educate your customers on what to look for, and what to do if they see something unusual.
Close observations can help detect leaks early and can prevent major water loss, as well as revenue loss, later.