The Environmental Protection Agency (EPA) and the Arizona Department of Environmental Quality (ADEQ) have requested that public water systems (PWS), especially large ones like Tucson Water, increase the transparency and accessibility of their implementation of the Lead and Copper Rule (LCR) to customers. Tucson Water’s lead and copper monitoring program has been in place for decades to assure customers that their drinking water meets all required standards.
Sources of Lead and What You Can Do to Minimize Risks
High levels of lead and copper are not present in the groundwater or in the recharged Colorado River water that serve as our drinking water sources. The metals are introduced by corrosion of household plumbing systems, service lines, as well as erosion of natural deposits. Most lead and copper in our system comes from lead-containing solder in older plumbing or from faucets or other water fixtures in homes and businesses.
When corrosive water stands in plumbing that contain lead for several hours, for example as in the morning or after returning from work or school, the lead may dissolve into drinking water.
To minimize the risks of exposure to lead, use water from the cold tap for making baby formula, drinking, and cooking. Let the water run for a minimum of 30 seconds to two minutes if it hasn’t been turned on for six or more hours.
Health Effects of Lead and Copper
Infants and children who drink water containing lead in excess of the action level could experience delays in their physical or mental development. Children born to women exposed to elevated levels of lead during pregnancy may experience developmental delays. Children could show slight deficits in attention span and learning abilities. Adults who drink water containing elevated levels over many years could develop kidney problems or high blood pressure. Copper is an essential nutrient, but some people who drink water containing copper in excess of the action level over a relatively short amount of time could experience gastrointestinal distress. Some people who drink water containing copper in excess of the action level over many years could suffer liver or kidney damage.
What the EPA, ADEQ, and Tucson Water Are Doing
Congress passed the Lead Ban on June 19, 1988. The ban required that pipe materials used in drinking water systems be "lead free." "Lead free" is defined as not having more than 0.2% lead in solders and flux, and no more than 8% lead in pipes. The requirement was later reduced to 0.25% in the wetted surface material in pipes on January 2014.
Under the authority of the Safe Drinking Water Act , Congress authorized the USEPA to establish the Lead and Copper Rule (LCR), which sets special health-based drinking water standards for lead and copper called action levels. ADEQ oversees the implementation and enforcement of the LCR in Arizona.
Tucson Water is regulated by ADEQ and both entities ensure that the levels for both metals are not exceeded in more than 10 percent of the homes sampled. The value that is used to determine compliance with the action level is called the 90th percentile. Tucson Water's Water Quality Management Division monitors and reports the lead and copper result to ADEQ and participating customer to meet the requirements of the LCR.
If more than 10 percent of the tap water samples exceed the lead action level of 15 parts per billion, the Tucson Water is required to take additional steps.
Tucson Water has ten public water systems: the main system and nine smaller, isolated systems (see map below).
Tucson Water utilizes a modeling software to track the corrosion status in the main system. Saturating the water with calcium carbonate leads to the formation of calcium carbonate precipitate in pipes that help reduce corrosion by providing a barrier on the pipe wall which prevents water from coming into contact with and corroding the pipe material. To ensure the right balance is obtained, the calcium carbonate corrosion potential (CCCP) and Langelier Index (LI) are tracked. For water to be considered balanced, it is desirable to have a CCP range between 4 mg/L and 10 mg/L and LI of -0.5 to +0.5 mg/L.
Tucson-Water Thunderhead PWS
Thunderhead PWS (see map below) is located in the southeastern part of the city serving a population of 162. In 2004, during routine monitoring of the system, the 90th percentile was calculated at 24 parts per billion (ppb), exceeding the maximum lead action level of 15 ppb. ADEQ approved Tucson Water’s proposed corrosion control treatment technique (CCT) in 2005. The CCT consists of aerating the water to raise its pH and reduce the corrosivity of the water. As part of the CCT requirements, the pH of the water is monitored at least monthly and the aerator is adjusted as necessary to ensure the pH falls within the set ADEQ limits. Recent pH values are graphed in Chart 1. Additional inorganic parameters are also monitored quarterly. Since 2005, the lead levels have been well below the action levels.
Materials Surveys for Lead
EPA regulations require that homes and businesses that are considered the most susceptible to high lead and copper concentrations be used as the sampling sites for lead and copper. The most susceptible sites are called Tier 1 sites. If a PWS is unable to locate Tier 1 sites, then Tier 2 sites and then Tier 3 sites are used. Table 2 defines the tiers.
Corrosion does not typically occur in homes built before 1982 because minerals in the water have coated the inside of the plumbing system. According to EPA guidelines, homse built between 1982 and 1987 were likely to contain the highest concentrations of these metals.
Tucson Water completed its material survey of the main system in 1992. A total of 186 sites were identified as Tier 1 sites. Tucson Water will be doing more recent materials surveys for the remaining small systems prior to monitoring for lead and copper this year.
Optimization of Corrosion Control
ADEQ deemed the main system to be optimized in 2000. In 1999, Tucson Water tested for lead, copper, and corrosion parameters (pH, alkalinity, calcium, conductivity, and temperature) from the entry-points-to-the-distribution-system (EPDS) and distribution sample points. The difference between the 90th percentiles of the tap water lead results and the highest source water lead results were below the lead and copper alert levels.
Corrosion control was deemed to be optimized for the small systems serving under 50,000 persons by demonstrating that the lead and copper 90th percentiles from data collected from1993-1994 were below the lead and copper action levels for two consecutive six-month periods.
Monitoring for Lead and Copper
Customer tap water monitoring is the main factor for determining monitoring requirements and whether corrosion control treatment, source water treatment, public education; and/or lead service line replacement should be implemented.
As required by the EPA, homes built between 1982 and 1987 were identified throughout the PWS. Customers residing in these homes were selected at random to volunteer to collect samples inside their homes. Initially, Tucson Water monitored about 230 customer taps at all PWS at least bi-annually or annually. It currently monitors for lead and copper at 125 established customer taps every three years. The monitoring sites are located in different parts of Tucson. As shown in Table 3, the number of sites tested is proportional to the population served by each PWS; that is, the larger the population being served, the more sampling sites.
Chart 2 and Chart 3 compares the 90th percentile results from Tucson Water PWS against EPA’s lead action level. All results from these sites are well below the limits allowed by regulations.
Does Tucson Water Have Lead Service Lines in its PWS?
Since 1999, when Tucson Water established a Lead Service Administrative Directive, lead services have been removed when discovered in the system. It was an aggressive policy with the goal of removing lead services by November 1999. In addition, Tucson Water no longer allows the use of brass fittings with a lead content equal to greater than 0.25% in its distribution system, per EPA’s Lead Ban that was established in 2014.
Consequently, lead service lines are not routinely found in our systems. There are two remaining inactive services Tucson Water is aware of. They are located at Church/Pennington and 6th Ave/Pennington.
What is the Procedure for Removing Public Service Lines?
When a lead service line or fitting is scheduled to be replaced, staff from Tucson Water's Maintenance Division will notify the customer of the date scheduled for the work. Before that date, staff from Tucson Water's Water Quality Lab will drop off instructions to the customer on how to collect a pre-removal sample. When the lead service line replacement is completed, staff will flush the line and the WQL will drop off a second bottle for the collection of the post-removal sample. The samples will be analyzed and reported to the occupants and to ADEQ. For more information, see Maintenance Lead Service Removal Procedure and Water Quality Lead Service Removal Procedure .
What is a Private Water Service Line?
It is the portion of the water service pipe running from the private property line into the building. This pipe may be made of or contain lead.
What Happens if the Lead Action Level is Exceeded?
If more than 10 percent of the tap water samples exceed the lead action level of 15 parts per billion, then Tucson Water is required to take additional steps including:
- Taking further steps optimize its corrosion control treatment (for water systems serving 50,000 people that have not fully optimized their corrosion control).
- Educating the public about lead in drinking water and actions consumers can take to reduce their exposure to lead.
- Replacing the portions of lead service lines (lines that connect distribution mains to customers) under the water system’s control.
How Are Samples Collected?
Sample Collection Instructions and bottles are dropped off by Water Quality & Operations staff to participating customers. The customer collects the first-draw samples from a tap that is used regularly and at a tap where the water has stood in the pipes for at least six hours.
How Do I Know the Lead Results Are Accurate?
The lead and copper samples are analyzed by our Water Quality Lab, which is licensed by the Arizona Department of Health Services (ADHS).
Who Can I Contact to Have My Water Tested for Lead?
If you are concerned about lead in your water, you may wish to have your water tested. For a list of licensed labs that can analyze your water for lead and copper, see ADHS’s Licensed Environmental Laboratories search page.
Why Were the Monitoring Frequencies and Number of Households to Be Tested Reduced?
The Tier 1 sites were established in 1998-1992 and they were monitored for the initial monitoring requirements during this time. Most of the small systems were initially monitored during 1993-1994, except the Tucson Water-Thunderhead System and the Tucson Water-Police and Fire Academy System, which were purchased in subsequent years. Monitoring at these systems started in 1998.
Initial monitoring for lead and copper was repeated in 1998 and 1999 for the main and small systems respectively. The sites were chosen from a pool of 107 sites (5-20 sites for the small systems), which were selected from the 186 Tier 1 sites established from the materials survey that was completed in 1992.
The lead and copper alert levels were not exceeded during the initial monitoring phases for the main and small systems (1998 for the small systems and 1999 for the main system). 40 Code of Federal Regulations (CFR) 141.86(d)(4)(i) allows small systems to reduce their monitoring frequencies to annual monitoring and number of sites by half provided the lead and copper alert levels are not exceeded. The small systems were monitored for lead and copper annually from 1999-2001 and ADEQ granted triennially monitoring starting in 2004. ADEQ granted triennial monitoring in the main system in 2002 and it, along with the other small systems, continues to be monitored every three years.
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