July 2018

etecting leaks can be very

difficult for anyone. The most

experienced operator can have

difficulty in locating leaks. Some

people think that it is easy and that all

you have to do is go look for water

exiting the ground. Unfortunately, it is

not that simple. 

Water can follow rock ledges for

hundreds of feet before surfacing. If

the leak is in a creek crossing, it will

never show itself unless in a drought.

In cities, the water can easily enter the

sanitary or storm sewer system and

never surface directly over the


I thought some readers might be

interested in experiences that I’ve had

in conducting water loss surveys and

leak detection. 

The first example is from several

years ago in a small town in northeast

Kansas. The unaccounted for water

loss had continued to increase month

by month.

I was called to conduct a water loss

survey in the town to attempt to

identify any possible leaks. We first

tested the master meter to ensure

accuracy and eliminate any issues that

the meter could be creating and

resulting in a water loss. The master

meter tested accurate. Using sonic leak

detection equipment, the operator and I

began listening to the residential

meters for any sounds that would

indicate a water line leak. It wasn’t too

far into the survey that the meters on a

2-inch cast line indicated a leak. Before

using the ground mic, we opened sewer

manholes to see if there was a large

amount of flow. Sure enough, the

customers on that particular water line

showed a sizable amount of flow in the

sewer line. I then ground microphoned

the area of the 2-inch line, I was able to

narrow down the area of the leak to

within 20 feet. The line was exposed

and the repair was made. The water

loss was reduced. This leak was

approximately 20 gpm. That may not

seem very significant to many systems,

however when the supply is only 60

gpm, it is critical. 

Another experience was in southeast

Kansas. A rural water district had been

losing approximately 50 percent of the

water for several months. I was called

to assist in finding the possible large

leak. KRWA Tech Lonnie Boller also

assisted with this particular leak. When

we arrived we learned that the system

was split into several areas and each

area had a submeter to help monitor

water loss. After inspecting the changes

in the water usage in each area, we

narrowed it down to one that had the

particularly high usage. After that

Lonnie watched the master meter as the

operator and I closed valves down the

line until the meter kept spinning. We

knew then it was between the last two

valves that were closed. Lonnie started

at one valve and I started at the other,

walking towards each other. It wasn’t

long when Lonnie had found the leak.

The leak was on a 6-inch PVC line, out

in the pasture, then entering a creek.

The leak was approximately 30 gpm.

The sound of 30 gpm is obvious when

going through a partially closed

mainline valve. 

Just a short note regarding customers

that have leaks on their side of the

meter. In my experience, a low or

intermittent flow is often due to a toilet

that is continuously running because of

a failed flapper valve. It’s not

uncommon for a failed toilet tank valve

to allow 5,000 to 6,000 gallons per

month. A test on toilet tank valves is to

add a few drops of food color in the

tank. That will help determine if the

flapper is leaking. Another possible

place to look on the customer side of

In cities, the water can

easily enter the sanitary

or storm sewer system

and never surface

directly over the



By Tony Kimmi, Technical Assistant