All of the water Carlisle residents drink is stored in two massive million-gallon tanks on what is referred to as Basin Hill by the borough’s water treatment plant employees. But before it gets to resident’s cups, or even the tanks, the water goes through an intricate filtration and decontamination process.

It all starts in the Conodoguinet Creek.

Several hundred yards from Carlisle Water Treatment Plant on Long’s Gap Road, a man-made dam impounds water, allowing plant employees to take that water through the “headrace,” according to Pete Selan, the plant’s director, and an employee of the plant since 1985.

“The headrace serves as director of part of the creek for water that we can use to send through the Water Treatment Plant to reduce the contaminants and the algae and turbidity,” he said. “There’s pipes going underneath the road and they go into the basement where our raw water pumps are that bring water to and through the plant.”

Once the water is drawn from the creek and into the plant, it’s at that point chemicals are added to it.

Polyaluminum chloride acts like a “coagulate” to the solids in the water where it then settles in the plant’s sedimentation bases located outside of the plant. That way, the heavy materials in the water settle to the bottom and the cloudiness dissolves, since creek water is far from clear.

Back inside, the water is then transferred to eight filter basins inside of the plant where it’s filtered through an archaic, yet according to Selan, “very effective and typical method.”

The water is filtered through sand and then anthracite to remove whatever solids weren’t pulled from the outside basins. Carbon is added then for taste and odor control as well.

Clear, filtered and carbonated, the water then is transported through the underbelly of the facility. Once there, fluoride is added, as is chlorine to disinfect the water. At that stage, the water is constantly moving ... it never sits in the 50,000 gallon tank beneath the plant, because from there it’s moved to “Basin Hill,” the clearing just outside of the plant where the borough’s water is stored for residential use in one-million-gallon tanks.

“We’re producing clean water here, running it through an intense process, and that involves gravity, physically settling out the solids, then filtering it out anything that’s left to get it pristine,” Selan said.


To ensure the quality of the water and that the facility is running as it should, the Pennsylvania Department of Environmental Protection requires monthly and quarterly testing results from the plant, but will also send agents unannounced to perform “surprise inspections,” according to Selan.

“We have to follow the DEP’s regulations. They determine at what levels the chlorine should be and how clean the water is by measuring turbidity,” he added.

Of all the costs associated with keeping the facility up and running, the chemicals are the least of the three major costs. Electricity at the facility and staff salaries are the two main expenses.

According to Borough Manager Matt Candland, chemicals used to treat the water at the plant have cost the borough about $136,000 so far this year. The electricity expense totals about $189,000, and staff salaries for six operators, one mechanic and Selan total approximately $516,000.

Buying in bulk is the cheapest and most efficient way to purchase the chemicals needed to treat the water, so once a year plant employees draw up a specification on what’s been used and what’s needed, then open bids in April for the chemical companies.


One wall in the plant, which Selan seems to no longer pay much attention too, is laden with awards from top to bottom, most recently the 5-Year Excellence in Water Treatment Award by the 2016 Partnership for Safe Water.

“Some of these things don’t just happen overnight, these accomplishments occur over the long term due to careful attention to detail, regulatory compliance and long term strategic planning,” Candland said.

The water residents drink may come from a source laden with trash and even fish—who are specifically screened for through a grated mesh cover over the dam’s headrace — however, Selan said that’s typical of many water sources for any given municipality.

Still, along with the DEP-required testing, the plant once a year sends out an annual report to all residents and borough staff in an effort to stay transparent and ensure people drinking the water throughout Carlisle it’s been filtered and is safe to consume.


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