Acceptable Water Loss in Distribution System

[Gossman]

Hi Everyone,

What would be an acceptable percentage of water loss within a distribution system?

The amount of water loss due to breaks and all bleeders are accounted for through either the Water Treatment Plant or the appropriate meters however, the percent of unaccounted for water still ranges between %15-%35. What could be the cause of this fluctuation? Is this amount of loss normal?

Thanks,

Goss

 

[bimr]

It depends on many factors and there is no universal standard, but if you want a single number, then 10% water loss is probably a realistic number for an efficiently operated water utility.

"The difference between water pumped or purchased and water that is metered or confidently estimated. Unaccounted for water should include, meter problems (i.e. master meter inaccuracies, domestic and non-domestic meter under-registration, etc.), unauthorized hydrant openings, unavoidable leakage, recoverable leakage, illegal connections, stand-pipe overflows and data processing errors.”

See the report:

http://www.awwa.org/files/science/WaterLoss/AWWA-WaterLossPolicy.doc

 

[Gossman]

Thanks for the info!

 

[stephensnelson]

I'm dealing with this very issue for a local municipality and the amount of "lost water" will be related to all the factors mentioned above as well as the age of the system, whether or not fire fighting related usage is metered (my current client does not) and if public buildings are metered (many municipalities do not meter their own usage). Currently this entity has a 33% loss in their system

 

[MiketheEngineer]

It's called a leak!!

 

[emmgjld]

Western Colorado 15% to 20% is commen

 

[BenJohnson]

A lot can depend upon your location. In Southern California, where droughts are somewhat common, even a 10% loss is a problem. I suppose the opposite is true if you live in a rain forest.

Many techniques are available to locate problem areas in water pipes: pressure tests, video camera, etc. Its prudent operations of a water company to know where problems areas are located in the system and factor them into the routine maintenance program. Remember, the original water network probably didn't take into account large water loses.

So, in case of a fire, or high demand day, the system (including the reservoir) may not be able to perform up to standards. 35% water loss may not be a lot if you have plenty of water, but it is a very big deal if the fire department suddenly looses water pressure.

 

[chicopee]

I wonder how much water loss there is in Boston, MA as they get their water from Quabbin reservoir some 90+ miles away. Iheard that Boston still has wooden pipes.