The White House Utility District in Tennessee covers more ground than any other water utility in the state. It serves about 90,000 homes and businesses. Since 2015, it has been using data to cut water losses, and a new paper published in December 2017 explains how that saved its customers money.
The work began when demand for water was rising. Early estimates showed the utility might have to spend $15 million to $20 million on new transmission lines and a bigger treatment plant. Running that extra capacity would cost more too, because energy alone makes up about 30 percent of the cost of producing water.
So the utility tried another path. It worked with OSIsoft, Matchpoint, ESRI and Hydreka on a system of software and smart meters that finds leaks underground.
What the data found
In 2012, the district’s infrastructure leakage index stood at 2.86. That meant about 32 percent of its water was escaping through leaking mains. In less than four days, the new system showed that a local stream was really a broken main. It was losing about 147 million gallons a year, which is enough for 2,239 homes.
Over two years, the utility recovered $900,000 worth of water. Its leakage index fell to 1.49, and it aims to go lower. It also avoided $200,000 in SCADA upgrades and won back $30,000 in staff time. Reports on possible problems now take 10 minutes instead of six hours.
Most of all, the district skipped a costly expansion. Bond interest alone would have run about $600,000 a year, and the utility now expects it will not need a major expansion until 2028.
The method is simple. The service area was split into 33 metered districts, and their data flows into the PI System from OSIsoft. Crews watch use between 1 a.m. and 4 a.m., when few people are awake. If a district uses more than half a gallon per minute per household in those hours, the software narrows down where a leak may be. The data then goes onto ESRI maps so crews can plan repairs.
Carl Alexander, GIS director at the utility, said one major leak would never have been found without the system. He added that crews now spot possible leaks every day, even small ones that could have gone unnoticed for years. Meanwhile, Gary Wong of OSIsoft said these tools work for utilities of any size, not only big ones with large engineering teams.
Leak repair also costs less than new supply. According to Bluefield Research, recovering water from leaks costs about $1.21 per 1,000 gallons in the US, while traditional sources cost $3.90 and desalination more than $8.00.
