Getting the lead out
When Washington, D.C., discovered elevated lead levels in its drinking water in July 2002, water utilities throughout the country began scrutinizing their practices for controlling waterborne lead. Managers knew that, in sufficient quantities, lead consumption could be dangerous to residents, particularly young children, infants and fetuses.
In most circumstances, lead is not present in the drinking water produced at municipal water treatment plants. It enters the water following contact with lead-containing components in the distribution system, such as lead service lines or in homes where solder containing lead joins copper pipes. Hence, utilities face the task of replacing their lines as well as encouraging, if not requiring, homeowners to do the same.
What happened in D.C.?
The high levels of lead in Washington’s water were attributed to a change in chemical disinfectant and the resulting reactions with lead in the distribution system’s components. To address the problem, the District’s Water and Sewer Authority (WASA), added orthophosphate — a corrosion-inhibiting chemical — to the water supply, is replacing all lead service lines and began extensive monitoring. WASA also immediately launched a public education program.
The Authority’s Board of Directors agreed to replace all of its lead service lines over six years and negotiated special rates so homeowners could replace the private portion of the lead-laced service lines. To date, several thousand lead service lines have been replaced. “Monitoring results indicate that the lead levels in the water supply have substantially dropped, but further analysis is needed,” says WASA Water Quality Manager Richard Giani.
Madison, Wis., discovered that treating water to avoid waterborne lead problems could lead to another problem. When the city exceeded EPA’s allowable level of lead in drinking water (15 parts per billion), it had to reduce the lead corrosion in its pipes. However, adding orthophosphate — the only compound that would meet EPA lead level standards — to the drinking water would have exceeded the city’s wastewater treatment systems capacity to remove phosphorus. It also would have significantly increased phosphorus loading in area lakes from drinking water entering the stormwater system or by direct runoff from outdoor use of the drinking water (washing cars, lawn sprinkling).
“Those impacts would have affected the whole community, not just those customers with lead service lines,” says Madison Water Utility General Manager David Denig-Chakroff. “We needed an alternative to chemical treatment, so we decided to go to the root of the problem and replace the approximately 11,000 remaining lead water service lines in the city over a 10-year period.”
The most difficult part of Madison’s plan was replacing both the utility’s and the homeowners’ lead service lines. Because legal and liability issues prevented Madison from working on private property, the city passed an ordinance requiring property owners to replace lead service lines at the same time the city replaces the lead service line adjacent to the homeowner’s property.
The city also created an incentive for the homeowners to cooperate. “Madison established a reimbursement program, whereby any customer who replaces a lead water service line on private property in accordance with the city ordinance, can apply for reimbursement of half the cost of replacement, up to $1,000,” Denig-Chakroff says.
For low-income customers, Madison pays the entire plumbing cost but places a lien on the property for half the cost. The city started the program to replace approximately 6,000 utility-owned service lines and 5,000 customer-owned service lines in January 2001. By the end of August 2005, Madison had replaced 4,214 utility-owned service lines, and customers had replaced 3,494 lines.
“As of September 2005, we have replaced 70 percent of the lead service lines, and we are over two years ahead of schedule for meeting our 10-year deadline for replacement,” Denig-Chakroff says. “With so many utilities now facing difficulties maintaining low lead levels or needing to change their corrosion control treatment to maintain compliance with federal standards, it’s becoming more clear that we made the right choice to target the source of the lead and remove the source from the system,” he says.
Denig-Chakroff reports that some lead particulates remain stranded in the plumbing system after replacement. “But our post-replacement sampling program is showing that, over time, without the service line providing a source of lead, stranded particulates are flushed out and lead levels will continue to decline,” he says.
Lead monitoring is difficult
Utilities have discovered that complying with the specific monitoring requirements of the Lead and Copper Rule (LCR) — EPA’s regulation to control lead and copper in drinking water — can be difficult. For example, a one-liter sample of water must be collected from the homeowner’s kitchen sink tap only after the homeowner stops using water throughout the entire home for six to eight hours.
Because it is difficult to gain access to customers’ homes to collect the samples, many utilities must rely on residents to collect the samples, which can lead to errors. While errors do not invalidate samples once they have been sent to the laboratory, water utilities cannot ensure samples are collected within the prescribed time or with proper collection procedures.
“We frequently find it necessary to call customers several times to remind them to provide samples or return the associated questionnaire,” says Jeff Swertfeger, supervising chemist at the Greater Cincinnati Water Works. “For a system of our size, which collects hundreds of lead samples each year, coordinating and completing the sampling is a big effort.”
Swertfeger says utilities also can experience problems when the residential sampling reveals high lead levels in homes with poor plumbing. “Under the current requirements, a municipal utility could exceed the Action Level — requiring drastic action — because of a situation outside its control,” he says.
Water contamination at schools
The discovery of high lead levels in water at schools and child-care facilities in several large American cities recently has gained national attention. Although each school or child-care administrator is legally responsible for the lead levels in those water systems, water utilities have been assisting the facilities.
The Philadelphia Water Department, for example, has joined with the city’s Department of Public Health to help reduce children’s lead exposure. “Even though Philadelphia’s drinking water is optimized for corrosion control, a percentage of taps in schools were found to have elevated lead,” says Gary Burlingame, administrative scientist in the Bureau of Laboratory Services for the Philadelphia Water Department.
Having identified which taps in the public schools needed attention, U.S. EPA Region III, the Philadelphia Department of Public Health (Childhood Lead Poisoning Prevention Program), the School District of Philadelphia and the Philadelphia Water Department shared responsibility for mitigating the elevated levels of lead in the drinking water. “The interpretation of lead sampling results from homes — let alone from buildings with complicated plumbing systems such as schools — can be quite challenging because such buildings have multiple potential sources of lead,” Burlingame says. Sources could include rust sediment, solder particulates and brass-containing faucets. “The Philadelphia Water Department brought its technical expertise with tap water sampling and testing, interpretation of water quality data and corrosion control to assist in guiding effective remediation strategies based on sound interpretations of the sampling data,” he says.
Burlingame says that the first step toward solving a lead contamination problem is making sure that the utility’s water has been adequately tested and optimized for corrosion control before determining if the water quality is stable as it moves through the distribution system and into customers’ homes. Otherwise, the efforts taken by the schools to mitigate elevated lead levels will be complicated by variability in water quality. Beyond that, the water utilities’ ability to help local health authorities and school managers will vary with their levels of expertise and resources.
“Some utilities can provide extensive assistance, and others do not have that capability,” Burlingame says. “Nonetheless, communities need to know that their water utilities are aware of the situation and in agreement with the measures being taken to provide safe drinking water.”
The national picture
In anticipation of new regulations — including one to control harmful compounds formed by the addition of disinfectants, such as chlorine — many water utilities are considering significant changes in their treatment processes, including changing the disinfectant applied to water before it enters the distribution system. Washington’s experience has shown that communities must be prepared for the consequences of changing their disinfection strategies.
Successfully managing lead in drinking water requires careful attention to optimum operational and treatment practices combined with diligent monitoring of corrosion control parameters and community outreach. Through such careful consideration and attention, municipal utilities can help provide a plentiful supply of safe drinking water to the communities they serve.
Kevin Dixon is a Philadelphia-based senior water quality specialist with B&V Water, the Kansas City, Mo.-based global water business of Black & Veatch.
Manuals offer guidance for managing lead
Convincing homeowners to replace their lead service lines is difficult because it is disruptive and can cost up to $10,000 per household. To help utilities encourage their customers to replace lead-lined pipes, the Denver-based American Water Works Association (AWWA) is offering “Strategies to Obtain Customer Acceptance of Complete Lead Service Line Replacement.” The manual, developed by Kansas City, Mo.-based Black & Veatch, summarizes the Lead and Copper Rule’s lead service line replacement regulatory requirements. It lists steps to prepare for complete lead service line replacement; provides examples of financial incentives utilities can offer homeowners to help pay the replacement cost; offers public communications strategies and follow-up actions a utility can take after replacing the lead service line; and recommends record keeping procedures. The strategy is based on proven techniques and experiences from utilities that have implemented successful replacement programs. The manual will be available from AWWA this month.
AWWA also is offering “Assisting Schools and Child-Care Facilities in Addressing Lead in Drinking Water,” which describes the steps school systems and child care facilities can take to effectively manage lead levels in their water supplies. Both documents are available from AWWA at www.awwa.org/Advocacy/govtaff/ or by contacting AWWA at 800-926-7337 and both are available free of charge to AWWA member utilities.