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Lead in Water

Lead in Water

Is Lead or Copper in Water a Problem in Boulder?

National Health Focus on Lead

Over the past two decades, a number of federal efforts have focused on reducing the public's exposure to lead. Because an estimated 20 percent of the average American's exposure to lead is through drinking water, the United States Environmental Protection Agency (EPA) has made it a priority through recent regulations to reduce lead in potable water.

The most recent mandate is the "Lead and Copper in Drinking Water Rule" (LCR). In 1992, to meet LCR requirements, the city began monitoring lead and copper levels at a number of Boulder residences.

Boulder's Monitoring Program

The water processed by Boulder's two water treatment plants is virtually free of lead and copper. These metals are introduced into drinking water mainly from home plumbing where copper pipes and lead solder are commonly found.

This is why in 1986 the EPA banned lead solder in all new home plumbing. Since it has been determined that most lead is leached from solder within five years, the systems identified by EPA to be at risk are those built between 1982 and 1987. Therefore, only the Boulder sites built or having plumbing changes within this time span are chosen for the monitoring program.

Monitoring Results

For lead and copper testing, the city samples 50 to 60 homes every three years. Samples are collected at the tap, after water has been in contact with the in-house plumbing overnight. The "first flush" sample is intended to capture worst-case metal levels.

Lead and copper levels from the city's testing have been below the regulatory action level. The regulatory lead and copper action levels are 0.015 and 1.3 parts per million (ppm), respectively.

What the city is doing to reduce lead

Boulder has implemented a Corrosion Control Program that changes the water chemistry to make the water less corrosive.

Most of Boulder's water comes from snowmelt which is naturally low in minerals. Water with a low mineral content is corrosive to pipes. Corrosion control processes at the water treatment plants reduce the tendency for lead and copper to dissolve out of home plumbing. They also help reduce the incidence of "rusty water" due to corrosion of iron pipes.

Corrosion control processes at the Betasso Water Treatment Plant involve the addition of two substances:

  1. Calcium (using calcium hydroxide from naturally occurring limestone) to adjust mineral content
  2. Carbon dioxide to adjust the pH (acid-base balance) of the water. The result is less corrosive water.

The Boulder Reservoir Water Treatment Plant's water has a higher mineral content which is within the alkalinity and pH range needed for corrosion control to match the Betasso treated water.

Additional benefits of the corrosion control program include an anticipated reduction in the failure rate of both city pipes and residential plumbing and a reduction in the metals that are processed by the Wastewater Treatment Plant.

Industrial and commercial water users may want to note these changes and make adjustments as needed.

Water Quality Resources