Manassas water supply is safe, city report says
Jim Johnston, water and sewer superintendent, said he has testimonials to support the city’s latest assessment.
“[We] take samples down to the junior high school, elementary schools for taste tests. They always pick our water, even over Deer Park. We’re looking into what we can do to sell the water bottled,” Johnston said.
During the late 1990s, Manassas violated EPA guidelines when the city failed to report levels of lead and copper in its water supply. Coliform, a bacteria that suggests other forms of contamination, was discovered at one point in 1997.
“It was an indication the chlorine wasn’t effective,” Johnston said.
Problems with bacteria usually arise on lines where water fails to cycle through the system.
For the past two years, Manassas has regularly opened fire hydrants to flush such lines. A greater number of lines are also being looped back into the system.
“There’s a long way to go. But we’re tackling some each year,” Johnston said.
The Virginia Division of Drinking Water has listed Lake Manassas, the source of most of the city’s water, as having a high susceptibility to contamination because of nearby homes, gas stations and other facilities.
Hamid R. Golesorkhi, the division’s Northern Virginia district engineer, said that the closeness of Manassas’ water source to possible contaminants is not a rare find.
“It’s my opinion that many jurisdictions have a high risk for contamination if they use a surface source of water,” he said.
To ensure water quality, Johnston said, Manassas has gone above and beyond state and federal regulations by having a program to help control activities around the lake.
The city regularly warns property owners near the lake of substances that might pollute Manassas’ drinking supply. When boaters still had access to the lake, only electric-powered motors were allowed.
“We regulate all the land use around the lake we can,” Johnston said.
Almost all of the city’s water comes from its treatment plant off the lake.
The plant, capable of treating up to 14 million gallons of water per day, supplies Manassas’ 35,000-plus residents. Water also is sold to Manassas Park and Prince William County, bringing the total number served to 70,000.
The water is filtered by two older “time-proven” systems installed in the late 1960s and 1970s, as well as a third newer “super-pulsator” system that went online in 1997.
All of the filter processes treat the water with aluminum sulfate, which sticks to particles in the water and forces them to sink.
The super-pulsator, which filters a third of the water supply, flows the water up between metal plates, allowing sludge that forms to sink in a way that is more efficient than the older filter systems, which run the water through carbon and sand.
“We’ve just recently in the last six months studied the pulsator and changed the chemical mix to make it perform even better,” Johnston said.
Staff writer Chris Newmarker can be reached at (703) 368-3101, Ext. 119.