Health officials say Lone Star Lake’s water is safe for swimming and other recreational uses — at least for now.

Richard Ziesenis, director of environmental health at the Lawrence-Douglas County Health Department, said three rounds of tests determined what officials had hoped: Lone Star’s water is relatively free of fecal coliform bacteria.

But officials fear that adding even one new water-equipped cabin or home along the banks of the lake southwest of Lawrence could push health risks to an unacceptable level.

“The concern that I have right now is we still have some vacant lots out there that have not been built on yet,” Ziesenis said. “I just don’t see any feasible way to put a new septic system on any of those single lots out there. …

“We’re trying to put a gallon of milk in a quart jar. It just doesn’t work.”

Fecal coliform is a bacteria, present in sewage, that can come from people or geese, horses and other animals. Exposure to high concentrations of the bacteria — or ingestion of even a small amount — puts a person at increased risk of contracting E. coli, hepatitis or Giardia, three diseases that can lead to sickness or death.

Concerns about the bacteria surfaced earlier this year at the Douglas County Courthouse, as county commissioners considered requests from property owners at the lake for allowing three new connections to rural water lines. Such connections would require installation of septic systems, something the health department shies away from unless the property covers at least three acres.

A typical lot on the lake covers only a tenth of an acre, leaving more questions than answers when it comes to accommodating people wanting to install new sinks, toilets and showers near the county-owned lake.

The bacteria remains under control now, but that could change as existing septic systems fail in the coming years, said Craig Weinaug, county administrator. Waste that seems to be held out of the lake could find its way into what has been a public recreational outlet since the lake’s construction in the 1930s.

“It’s not a problem now, but it will be a problem someday,” Weinaug said. “We still need to address the problem that we anticipate having sometime in the future.”

Ziesenis said he would recommend placing a moratorium on new water connections on single lots at the lake.

About 20 single lots remain vacant at the lake, where the department has cleared seven septic systems for installation during the past 35 years. Other lots either have no systems or use systems installed before the health department’s regulations took effect in 1968.

County commissioners ordered the tests for fecal coliform to help them decide when they would be facing decisions about development regulations.

The health department twice conducted tests at eight locations in the lake.

In May, four tests conducted at the southern end of the lake, near lakeside cabins, revealed the presence of bacteria but remained below the state’s limit of 200 colonies per 100 ml. The results ranged from 5 colonies per 100 ml to 45 colonies per 100 ml.

At the northern end of the lake — near the dam, marina and public swimming area — samples were clean. Only one sample contained 5 colonies per 100 ml.

Subsequent tests — in July and August — revealed even lower concentrations of the bacteria, Ziesenis said. In many cases, not even a trace could be detected.