Dillon residents should expect to receive a letter from the town’s Public Works Department about the discovery of lead in the water of some local homes.
Dillon Public Works director Scott O’Brien said Wednesday the letter is a stock document from the U.S. Environmental Protection Agency the town is mandated by law to deliver when the presence of lead is discovered in finished water. Although it provides helpful information about health effects of lead, where it comes from — it’s a naturally occurring metal — and steps locals can take to minimize exposure, the letter provides few details about what is happening locally, O’Brien said.
First off, he said, there are no traces of lead in the water Dillon delivers to local homes or in its source water from the Continental Divide. However, residents could be at risk of lead leeching into finished water through solder, pipes and plumbing fixtures with high levels of lead.
“It’s not an uncommon problem,” O’Brien said. “Lead was used for a variety of things throughout history, and lead pipes were very common for a long time, until we later discovered it’s toxic and we need to limit exposure.”
High levels of lead exposure have been connected to kidney and brain damage and to birth defects. In 1986, at the urging of the EPA, Congress passed several amendments to the Safe Drinking Water Act of 1974 to reduce lead exposure. Notably, Congress passed rules to drastically reduce the presence of lead in solder and household plumbing.
However, O’Brien said buildings constructed before 1986 likely have pipes and plumbing fixtures containing high levels of lead. Therefore, in addition to drastically reducing the amount of lead in household plumbing, Congress also required local water departments to regularly test finished water supplies for lead.
Every six months, the Dillon Water Department tests 20 “Tier 1” sites. The EPA defines a Tier 1 site as a home built before 1986 that would likely be at high risk of lead exposure, O’Brien said.
The town regularly tests 20 sites. As part of the test, participating residents are asked not to run their water for six to eight hours. Lead leeches into standing and warm water more easily than cold running water, O’Brien said.
“If lead is going to get into the water, we want it to,” O’Brien said. “We need to be able to detect it, so we know there’s an issue.”
After the tests are conducted, the town has the samples analyzed by a third party in Denver. The EPA stipulates a passing grade of 90 percent, O’Brien said, which means if two or fewer homes exceed target levels for lead of .015 parts per million, the town is not required to take action.
For the first time in his 23 years with the town of Dillon, the latest round of testing yielded three samples that exceeded EPA target levels. The EPA issued an action order requiring the town to hire an independent engineering firm to investigate the source of rising lead levels in finished water and to come up with a solution.
The town hired HDR Inc., a firm based in Omaha with offices in Colorado. HDR completed its report in February and the town has already invested $20,000 in a new treatment system. The system is scheduled to come online in about a month and should immediately affect lead concentrations in finished water, O’Brien said.
The town will conduct its next lead testing in the fall.
Raising the Ph
If the town’s source water and water treatment plant are not responsible for the lead in finished water, residents — even those living in high-risk homes built before 1986 — may be wondering how lead levels have remained low until now. The answer is that the chemistry of Dillon’s source water has changed.
Water is a universal solvent, O’Brien said, which means it naturally absorbs minerals as it flows down from the Continental Divide. Mineral content refers to a water’s hardness, and the harder the water the less inclined it is to allow lead leeching.
In addition to hardness, there are three other characteristics that contribute to lead leeching, including temperature, pH and alkalinity. Different combinations of high and low levels of those four characteristics can have positive or negative effects on water quality. Dillon’s water is low on all fronts.
Dillon’s water is delivered to residents at four degrees above freezing, which is beneficial because lead does not leech easily into cold water, O’Brien said. The town’s water historically has had low alkalinity and water hardness levels, which would make finished water more prone to lead leeching, O’Brien said. The equalizer for so many years has been Dillon’s pH level, but that has been declining steadily for decades.
When O’Brien started working for Dillon, the pH level of the town’s water was 7.8. In the last 23 years it has dropped to 7 for unknown reasons.
Officials and engineers concluded that raising the town’s pH level to 8 would be the easiest course of action to prevent further lead leeching in local homes.
“There’s nothing we can do about temperature, alkalinity or hardness because that’s how we get our water when it flows down from the Continental Divide,” O’Brien said. “We can do something about the pH, and increasing it from 7 to 8 will help reduce the amount of lead that is able to leech into people’s finished water.”
In addition to the $20,000 cost of the treatment system, raising the pH level from 7 to 8 is estimated to cost the town about $3,000 annually.
Residents interested in learning more about lead leeching and the steps the town is taking to reduce exposure can call the Dillon Water Department at 468-2403.