San Francisco Water Meters to Detect Leaks, Help Customers Track Usage

Embedded with digital chips, meters to track hourly usage, send e-mail alerts when consumption spikes.

by / June 18, 2010

San Francisco started replacing its 175,000-plus water meters in June with high-tech devices that will eventually allow customers to view their water use online and eliminate the need for manual meter readers.

The San Francisco Public Utilities Commission (SFPUC) on June 7 began its automated water meter program, a two-year effort to replace all residential and commercial water meters in the city. The new meters use low-frequency radio signals to collect hourly water use and transmits that data four times a day to the SFPUC billing system. The $50 million program is being funded by a 91-cent fee that's being tacked onto ratepayers' monthly bills.

"It's a great tool in looking for potential spikes in usage and leaks," said Heather Pohl, SFPUC automated water meter program project manager. "So we can, in real time, help people monitor and manage their water use more effectively."

While San Francisco's utility commission is the first major California water utility to install the technology, according to the SFPUC. The utility is following a nationwide trend of other cities that have deployed similar technologies. Boston; Washington, D.C.; and Kansas City, Mo., use the same meter-reading system, and New York City and Toronto are starting extensive projects with the same technology, according to a SFPUC frequently asked questions page.

Public utilities across the country have also started installing smart electricity meters with similar functionality in millions of homes and businesses.

Currently most residential water meters are read by meter readers once every two months, and commercial meters are read every month. But this "intensive and infrequent" process can result in bill estimations when the readers can't be accessed due to parked cars and other obstructions. It also doesn't allow for water leaks to be quickly detected, which can result in more expensive monthly bills. The automated water meter system will nix both issues by collecting more frequent consumption data and flagging water consumption surges.

Eventually the commission hopes to send e-mail alerts to customers if there's an unusual amount of water being used, which may allay undetected leaks.

"If they've got a leak now, and toilet leaks happen every day, they can result in a lot of water loss, and right now they won't know," Pohl said. "It gives them tools to understand what they're paying for."

How the Technology Works

The automated water meter system -- brand name Aclara Fixed Network AMI STAR System -- uses a wireless fixed network system with three components. The meter transmission unit, connected to the water meter, "reads" the meter every hour and sends its information to the data collection unit every six hours.

There will be about 70 data collection units throughout the city on SFPUC facilities and city-owned poles and rooftops, which will transmit meter readings to the SFPUC's network control computer. The network control computer feeds into the SFPUC's billing system and calculates the amount of water used, creating statements.

The meter readings are transmitted via the automated network using a private radio frequency channel, from the meter box to data collectors, and using a cellular data network from the data collectors to the network control computer.

Testing, Safety, Security and Accuracy

Due to public safety concerns about radio frequency exposure levels, the SFPUC partnered with the Department of Public Health to evaluate the automated water meters' transmission levels. The signals turned out to be "well below" government limits with respect to radio frequency exposure levels, according to the SFPUC.

The technology has proven itself effective, and has been in use for more than 13 years, the SFPUC assures. Privacy concerns -- that personal customer

data may be unsecure -- have been assuaged, the utility says, as only the water meter readings, the meter identification number and diagnostic information will be transmitted. Personal customer information won't be sent and isn't part of the meter information or reads; for additional security, the data is encoded and transmitted over a privately licensed radio frequency channel.

To ensure the meter readings' accuracy, the SFPUC is guaranteeing the meters sent from the manufacturer meet American Water Works Association standards. Once a meter shipment reaches the city, SFPUC will randomly test 10 percent of the meters at its own certified testing facility before approving their installation.

But the commission isn't stopping there. To ensure the transmitted data's accuracy even further, the SFPUC will randomly conduct quality assurance audits on 5 percent of the meters after installation. As part of the audits, SFPUC field staff will manually read the water meter dials and check them against the automated reading sent to the computer system.

The SFPUC meter readers will also visually verify the meters' accuracy by conducting one manual meter reading, checking the water dial against the SFPUC's computer system, for every installed meter.

While the SFPUC has promised customers they'll be able to view their water usage online, that component of the program may take longer, Pohl said. The customer Web interface is under development and she doesn't want to speculate on that time frame. "I feel really confident it will be within two years of deployment, but I can't say when," Pohl said. "It's high on the list of priorities, but it takes a long time for IT systems to be integrated."


Karen Wilkinson

Karen is a former staff writer for Government Technology magazine.