Not long ago in Westport, the environmentally-conscious debate centered on paper versus plastic. A similar discussion has been going on around town over the years, and the question is simple: septic or sewer? The answer is as murky as a slow-moving brook or the ground water potentially facing contamination.

"I think that a well-functioning septic system is just fine, but if you have septic systems that are in areas with high ground water ... then I think you're asking for water quality problems," said Alicia Mozian, director of the Conservation Department.

She added, "This town has 13 named water courses plus the unnamed tributaries, so we have a very wet town and a lot of the houses that were built in the 50s, 60s were built on filled wetland soils. Those septic [tanks] went in these areas where the soil might not have been the best."

Septic systems are used by approximately 6,000 properties in Westport, with the remaining 4,500 hooked up to town-operated sewage lines. Proper installation and maintenance of a septic system, which handles household waste disposed of through the sink, toilet and shower, can be a boon for the environment.

The septic system reduces a lot of the waste, and the soil and microbes help clean it up. But when something goes wrong, surface water, such as streams, rivers and lakes, can be affected.

What's less obvious is when ground water, which flows through pores in the earth, is affected. About 30 percent of homes in town get their water from wells, which extract ground water from water-bearing aquifers. In Westport, the protected aquifer area contains approximately 1,400 households. Contaminants that are flushed down the toilet or washed down the sink, such as medication, cleaning products or even coffee grounds, can have an adverse effect on the environment.

With Monday marking the beginning of "Ground Water Awareness Week," the Environmental Protection Agency (EPA) is hoping to spread the word about something that can't be seen. Although it flies under the radar, a fourth of all fresh water used in the U.S. comes from beneath the ground.

"This [pollution] is all underground and that's part of the danger. We don't see it," said Dick Harris, director of Harbor Watch/River Watch. "We have trouble reacting to things we do see. Things we don't see are a real mystery and most people don't think in those terms."

Harbor Watch/River Watch, which operates as part of the nonprofit Earthplace, aims to protect the ecology of the Long Island Sound and surrounding waterways in the area. Studies conducted by the organization on surface water, such as streams, have yielded valuable information on what's happening to the water.

Harbor Watch/River Watch does not analyze ground water, but other studies have documented some startling findings on the issue. A recent Yale University study, reported on in the Connecticut Post, showed that medications leaking into ground water via the sink or toilet have caused some male frogs in Connecticut to develop eggs in their testes. Egg producing is naturally a female frog's job. In agricultural areas, such findings were limited, but in suburban and urban areas the presence of mutated frogs was much more common.

Mark Cooper, director of the Westport Weston Health District, stressed that a properly engineered and maintained septic tank is a positive thing for the environment and keeps ground water healthy. Nowadays, soil testing is done to test the land's ability to clean the waste and the rate at which water can pass through the soil.

"A lot of thought goes into ... putting in a new septic system today," Cooper said. "That wasn't the case 50 years ago."

Before indoor plumbing became common in the 1930s and '40s, Cooper said outhouses were the norm. After plumbing became prevalent, the waste was typically just passed along into a stream. Cesspools were next, then septic tanks without any soil testing. Finally, engineering and science became common practice.

With a septic system, the water is placed back in the environment, so well use can be sustained. If a well user has a sewer line to dispose of waste, the water is taken out of the environment and eventually ends up in the Long Island Sound after treatment.

"There have actually been communities where once they put in sewers, they had to extend public water lines because the [ground] water dropped so low that it couldn't supply the wells," Cooper said.

With nearly 5,000 properties in town connected to sewer lines, Mozian and Cooper both said the lines also serve an important purpose, so the advantage of being connected to the line or having a septic system comes down to individual cases.

Sewer lines are best in heavily developed areas where soil isn't of the best quality, according to Mozian. One of those areas is Saugatuck Shores, where construction on a sewer line is ongoing.

"I'm just thrilled that the sewer [is going in] down there ... because the soils are so fast draining that you don't have the presence of the microbes to treat it before it gets into the Long Island Sound," she said.

Around town, through the Septic Education Task Force, efforts are being made to limit the impact of septic systems. With the aid of a $6,000 grant, a survey is being conducted to determine how informed people are about septic issues. A campaign is being kicked off this spring, which will include a "docudrama" showing at the Westport Youth Film Festival in May and via public service announcements.

After the campaign winds down, another batch of surveys will be conducted to gauge knowledge on the subject.

"Our initial indication from the `pre-survey' is that people are behaving pretty rationally and responsibly," said Jonathan Steinberg, co-chair of the task force. "We hope that awareness and knowledge of septic systems will improve, and that will hopefully be the key results when we file our report for the grant we received."